Implement variants tags inspector work

Implemented features:
- UI for the variants tags in the inspector.
- adding, renaming, and deleting tags.
- adding, renaming, and deleting tag groups.
- adding, renaming tags/groups is checked for name uniqueness across
  project.
- deleting tags/groups checked for in-use across the project.
- toggling tags state.
- tags are synced with the UIA/UIP.
- changing group color.
- the variants property in saved in the <Graph> part of the UIP.

Remaining tasks:
- implement import and export.
- issue: renaming a selected tag, toggle it unselected till next project
         load.
- issue: update the property after deleting a group that is in-use in the
         property in the currently open doc but not saved.
- thorough test and tweaking.

Task-no: QT3DS-2983
Change-Id: Iecbb6c854a00ec75864de5dd0f31f6ca3721c8ec
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>

20 files changed, 1633 insertions, 18 deletions

diff --git a/src/Authoring/Client/Code/Core/Doc/Doc.cpp b/src/Authoring/Client/Code/Core/Doc/Doc.cpp
index ecb16fb8..a7730603 100644
--- a/src/Authoring/Client/Code/Core/Doc/Doc.cpp
+++ b/src/Authoring/Client/Code/Core/Doc/Doc.cpp
@@ -2391,7 +2391,8 @@ std::shared_ptr<Q3DStudio::IComposerSerializer> CDoc::CreateSerializer()
                 *theCoreSystem.GetActionCore(), *m_AssetGraph, *theFullSystem.GetSlideSystem(),
                 *theFullSystem.GetActionSystem(), *theCoreSystem.GetSlideGraphCore(),
                 theClientBridge.GetObjectDefinitions(), m_ImportFailedHandler,
-                *theCoreSystem.GetGuideSystem(), *GetSceneGraph()->GetPathManager());
+                *theCoreSystem.GetGuideSystem(), *GetSceneGraph()->GetPathManager(),
+                *theFullSystem.GetPropertySystem());
 }
 
 std::shared_ptr<Q3DStudio::IComposerSerializer> CDoc::CreateTransactionlessSerializer()
@@ -2407,8 +2408,10 @@ std::shared_ptr<Q3DStudio::IComposerSerializer> CDoc::CreateTransactionlessSeria
                 *theCoreSystem.GetTransactionlessAnimationCore(),
                 *theCoreSystem.GetTransactionlessActionCore(), *m_AssetGraph,
                 *theFullSystem.GetSlideSystem(), *theFullSystem.GetActionSystem(),
-                *theCoreSystem.GetTransactionlessSlideGraphCore(), theClientBridge.GetObjectDefinitions(),
-                m_ImportFailedHandler, *theCoreSystem.GetGuideSystem(), *GetSceneGraph()->GetPathManager());
+                *theCoreSystem.GetTransactionlessSlideGraphCore(),
+                theClientBridge.GetObjectDefinitions(), m_ImportFailedHandler,
+                *theCoreSystem.GetGuideSystem(), *GetSceneGraph()->GetPathManager(),
+                *theFullSystem.GetPropertySystem());
 }
 
 std::shared_ptr<qt3dsdm::IDOMWriter> CDoc::CreateDOMWriter()
diff --git a/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.cpp b/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.cpp
index 09707e46..462549b5 100644
--- a/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.cpp
+++ b/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.cpp
@@ -321,6 +321,7 @@ struct SComposerSerializerImpl : public IComposerSerializer
     qt3dsdm::IStringTable &m_StringTable;
     std::shared_ptr<Q3DStudio::IImportFailedHandler> m_ImportFailedHandler;
     qt3ds::render::IPathManager &m_PathManager;
+    IPropertySystem &m_propertySystem;
 
     // The instances we have discovered when we are writing
     THandleToIdMap m_HandleToIdMap;
@@ -370,7 +371,8 @@ struct SComposerSerializerImpl : public IComposerSerializer
                             IActionSystem &inActionSystem, ISlideGraphCore &inSlideGraphCore,
                             SComposerObjectDefinitions &inObjectDefinitions,
                             std::shared_ptr<Q3DStudio::IImportFailedHandler> inFailedHandler,
-                            IGuideSystem &inGuideSystem, qt3ds::render::IPathManager &inPathManager)
+                            IGuideSystem &inGuideSystem, qt3ds::render::IPathManager &inPathManager,
+                            IPropertySystem &inPropSystem)
         : m_DataCore(inDataCore)
         , m_MetaData(inMetaData)
         , m_SlideCore(inSlideCore)
@@ -385,6 +387,7 @@ struct SComposerSerializerImpl : public IComposerSerializer
         , m_StringTable(inDataCore.GetStringTable())
         , m_ImportFailedHandler(inFailedHandler)
         , m_PathManager(inPathManager)
+        , m_propertySystem(inPropSystem)
         , m_Foundation(Q3DStudio::Foundation::SStudioFoundation::Create())
         , m_InputStreamFactory(qt3ds::render::IInputStreamFactory::Create(*m_Foundation.m_Foundation))
         , m_PreserveFileIds(true)
@@ -923,8 +926,10 @@ struct SComposerSerializerImpl : public IComposerSerializer
             const pair<Qt3DSDMPropertyHandle, SValue> &theValue(inList[idx]);
             TCharStr theName(m_DataCore.GetProperty(theValue.first).m_Name);
             WriteDataModelValue(theValue.second, theValueStr);
-            if (GetValueType(theValue.second) == DataModelDataType::String || theValueStr.size())
-                inWriter.Att(theName.wide_str(), theValueStr.wide_str());
+            if (GetValueType(theValue.second) == DataModelDataType::String || theValueStr.size()) {
+                if (theName != L"variants") // this property is saved under the <Graph> node
+                    inWriter.Att(theName.wide_str(), theValueStr.wide_str());
+            }
         }
     }
 
@@ -1607,6 +1612,15 @@ struct SComposerSerializerImpl : public IComposerSerializer
         IDOMWriter::Scope __instanceScope(inWriter, theType->wide_str());
         inWriter.Att(L"id", GetInstanceId(inInstance));
 
+        // for layers, save the variants property under the <Graph>
+        if (theType.getValue() == L"Layer") {
+            auto prop = m_propertySystem.GetAggregateInstancePropertyByName(inInstance,
+                                                                            L"variants");
+            SValue sVal;
+            if (m_propertySystem.GetInstancePropertyValue(inInstance, prop, sVal))
+                inWriter.Att(L"variants", get<TDataStrPtr>(sVal)->GetData());
+        }
+
         m_InstanceSet.insert(inInstance);
 
         Qt3DSDMSlideHandle theAssociatedSlide = GetAssociatedSlide(inInstance);
@@ -2854,10 +2868,10 @@ std::shared_ptr<IComposerSerializer> IComposerSerializer::CreateGraphSlideSerial
         ISlideSystem &inSlideSystem, IActionSystem &inActionSystem, ISlideGraphCore &inSlideGraphCore,
         SComposerObjectDefinitions &inObjectDefinitions,
         std::shared_ptr<Q3DStudio::IImportFailedHandler> inFailedHandler, IGuideSystem &inGuideSystem,
-        qt3ds::render::IPathManager &inPathManager)
+        qt3ds::render::IPathManager &inPathManager, IPropertySystem &inPropSystem)
 {
     return std::shared_ptr<SComposerSerializerImpl>(new SComposerSerializerImpl(
                                                           inDataCore, inMetaData, inSlideCore, inAnimationCore, inActionCore, inAssetGraph,
                                                           inSlideSystem, inActionSystem, inSlideGraphCore, inObjectDefinitions, inFailedHandler,
-                                                          inGuideSystem, inPathManager));
+                                                          inGuideSystem, inPathManager, inPropSystem));
 }
diff --git a/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.h b/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.h
index f02677f1..98fba780 100644
--- a/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.h
+++ b/src/Authoring/Client/Code/Core/Doc/IComposerSerializer.h
@@ -49,6 +49,7 @@ class IActionSystem;
 class ISlideGraphCore;
 class IGuideSystem;
 class SComposerObjectDefinitions;
+class IPropertySystem;
 };
 
 namespace Q3DStudio {
@@ -108,7 +109,8 @@ public:
         qt3dsdm::IActionSystem &inActionSystem, qt3dsdm::ISlideGraphCore &inSlideGraphCore,
         qt3dsdm::SComposerObjectDefinitions &inObjectDefinitions,
         std::shared_ptr<Q3DStudio::IImportFailedHandler> inFailedHandler,
-        qt3dsdm::IGuideSystem &inGuideSystem, qt3ds::render::IPathManager &inPathManager);
+        qt3dsdm::IGuideSystem &inGuideSystem, qt3ds::render::IPathManager &inPathManager,
+        qt3dsdm::IPropertySystem &inPropSystem);
 };
 }
 
diff --git a/src/Authoring/Studio/Application/ProjectFile.cpp b/src/Authoring/Studio/Application/ProjectFile.cpp
index ecf5a065..af80556d 100644
--- a/src/Authoring/Studio/Application/ProjectFile.cpp
+++ b/src/Authoring/Studio/Application/ProjectFile.cpp
@@ -43,6 +43,8 @@
 #include <QtCore/qdiriterator.h>
 #include <QtCore/qsavefile.h>
 #include <QtCore/qtimer.h>
+#include <QtCore/qrandom.h>
+#include <QtWidgets/qmessagebox.h>
 
 ProjectFile::ProjectFile()
 {
@@ -928,3 +930,609 @@ ProjectFile::getDiBindingtypesFromSubpresentations() const
 
     return map;
 }
+
+// load variant data from uia to m_variantsDef
+void ProjectFile::loadVariants()
+{
+    if (!m_fileInfo.exists())
+        return;
+
+    QFile file(getProjectFilePath());
+    if (!file.open(QFile::Text | QFile::ReadOnly)) {
+        qWarning() << file.errorString();
+        return;
+    }
+
+    m_variantsDef.clear();
+
+    QXmlStreamReader reader(&file);
+    reader.setNamespaceProcessing(false);
+
+    while (!reader.atEnd()) {
+        if (reader.readNextStartElement()) {
+            if (reader.name() == QLatin1String("variantgroup")) {
+                VariantGroup g;
+                g.m_title = reader.attributes().value(QLatin1String("id")).toString();
+                g.m_color = reader.attributes().value(QLatin1String("color")).toString();
+                m_variantsDef.append(g);
+            } else if (reader.name() == QLatin1String("variant")) {
+                m_variantsDef.last().m_tags.append(reader.attributes().value(
+                                                       QLatin1String("id")).toString());
+            } else if (m_variantsDef.length() > 0) {
+                break;
+            }
+        }
+    }
+}
+
+// Add a new tag to a variants group
+void ProjectFile::addVariantTag(const QString &group, const QString &newTag)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomElement newTagElem = domDoc.createElement(QStringLiteral("variant"));
+    newTagElem.setAttribute(QStringLiteral("id"), newTag);
+
+    QDomNodeList groupsElems = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"))
+                                     .elementsByTagName(QStringLiteral("variantgroup"));
+
+    // update and save the uia
+    for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == group) {
+            gElem.appendChild(newTagElem);
+            StudioUtils::commitDomDocumentSave(file, domDoc);
+            break;
+        }
+    }
+
+    // update m_variantsDef
+    for (auto &v : m_variantsDef) {
+        if (v.m_title == group) {
+            v.m_tags.append(newTag);
+            break;
+        }
+    }
+}
+
+// Add a new group, it is assumes that the new group name is unique
+void ProjectFile::addVariantGroup(const QString &newGroup)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomElement variantsElem = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"));
+
+    if (variantsElem.isNull()) {
+        QDomElement newVariantsElem = domDoc.createElement(QStringLiteral("variants"));
+        domDoc.documentElement().appendChild(newVariantsElem);
+        variantsElem = newVariantsElem;
+    }
+
+    // generate random semi-bright color
+    int r = 0x555555 + QRandomGenerator::global()->generate() % 0x555555; // 0x555555 = 0xffffff / 3
+    QString newColor = QLatin1Char('#') + QString::number(r, 16);
+
+    QDomElement newGroupElem = domDoc.createElement(QStringLiteral("variantgroup"));
+    newGroupElem.setAttribute(QStringLiteral("id"), newGroup);
+    newGroupElem.setAttribute(QStringLiteral("color"), newColor);
+    variantsElem.appendChild(newGroupElem);
+    StudioUtils::commitDomDocumentSave(file, domDoc);
+
+    // update m_variantsDef
+    VariantGroup g;
+    g.m_title = newGroup;
+    g.m_color = newColor;
+    m_variantsDef.append(g);
+}
+
+void ProjectFile::renameVariantTag(const QString &group, const QString &oldTag,
+                                   const QString &newTag)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    // rename the tag in all uip files
+    QDomNodeList presElems = domDoc.documentElement()
+                                   .firstChildElement(QStringLiteral("assets"))
+                                   .elementsByTagName(QStringLiteral("presentation"));
+    for (int i = 0; i < presElems.count(); ++i) {
+        QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+        renameTagInUip(pPath, group, oldTag, newTag);
+    }
+
+    // update and save the uia
+    QDomNodeList groupsElems = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"))
+                                     .elementsByTagName(QStringLiteral("variantgroup"));
+
+    bool renamed = false;
+     for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == group) {
+            QDomNodeList tagsElems = gElem.childNodes();
+            for (int j = 0; j < tagsElems.count(); ++j) {
+                QDomElement tElem = tagsElems.at(j).toElement();
+                if (tElem.attribute(QStringLiteral("id")) == oldTag) {
+                    tElem.setAttribute(QStringLiteral("id"), newTag);
+                    StudioUtils::commitDomDocumentSave(file, domDoc);
+                    renamed = true;
+                    break;
+                }
+            }
+            if (renamed)
+                break;
+        }
+    }
+
+    // update m_variantsDef
+     renamed = false;
+    for (auto &g : m_variantsDef) {
+        if (g.m_title == group) {
+            for (auto &t : g.m_tags) {
+                if (t == oldTag) {
+                    t = newTag;
+                    renamed = true;
+                    break;
+                }
+            }
+            if (renamed)
+                break;
+        }
+    }
+}
+
+// rename a variant group, newGroup is assumed to be unique
+void ProjectFile::renameVariantGroup(const QString &oldGroup, const QString &newGroup)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    // rename the group in all uip files
+    QDomNodeList presElems = domDoc.documentElement()
+                                   .firstChildElement(QStringLiteral("assets"))
+                                   .elementsByTagName(QStringLiteral("presentation"));
+    for (int i = 0; i < presElems.count(); ++i) {
+        QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+        renameGroupInUip(pPath, oldGroup, newGroup);
+    }
+
+    // update and save the uia
+    QDomNodeList groupsElems = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"))
+                                     .elementsByTagName(QStringLiteral("variantgroup"));
+
+     for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == oldGroup) {
+            gElem.setAttribute(QStringLiteral("id"), newGroup);
+            StudioUtils::commitDomDocumentSave(file, domDoc);
+            break;
+        }
+    }
+
+    // update m_variantsDef
+    for (auto &g : m_variantsDef) {
+        if (g.m_title == oldGroup) {
+            g.m_title = newGroup;
+            break;
+        }
+    }
+}
+
+void ProjectFile::deleteVariantGroup(const QString &group)
+{
+    CDoc *doc = g_StudioApp.GetCore()->GetDoc();
+
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    // check if group is in use in other presentations in the porject
+    int inUseIdx = -1; // index of first presentation that has the group in-use
+    QDomNodeList presElems = domDoc.documentElement()
+                                   .firstChildElement(QStringLiteral("assets"))
+                                   .elementsByTagName(QStringLiteral("presentation"));
+    for (int i = 0; i < presElems.count(); ++i) {
+        QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+        if (groupExistsInUip(pPath, group)) {
+            inUseIdx = i;
+            break;
+        }
+    }
+
+    // check that the group is in use in the current doc (could be set in the property but not saved
+    if (inUseIdx == -1) {
+        auto propertySystem = doc->GetStudioSystem()->GetPropertySystem();
+        int instance = doc->GetSelectedInstance();
+        auto bridge = doc->GetStudioSystem()->GetClientDataModelBridge();
+
+        if (instance != 0 && bridge->IsLayerInstance(instance)) {
+            int property = propertySystem->GetAggregateInstancePropertyByName(instance,
+                                                                              L"variants");
+            qt3dsdm::SValue sValue;
+            if (propertySystem->GetInstancePropertyValue(instance, property, sValue)) {
+                QString val = QString::fromWCharArray(
+                              qt3dsdm::get<qt3dsdm::TDataStrPtr>(sValue)->GetData());
+                if (val.contains(group + QLatin1Char(':'))) {
+                    // this big value will trigger the in-use warning, but will skip updaing the
+                    // uips which is not needed.
+                    inUseIdx = 9999;
+                }
+            }
+        }
+    }
+
+    if (inUseIdx != -1) {
+        QMessageBox box;
+        box.setWindowTitle(tr("Group tags in use"));
+        box.setText(tr("Some tags in the Group '%1' are in use in the project, are you sure you"
+                       " want to delete the group?").arg(group));
+        box.setIcon(QMessageBox::Warning);
+        box.setStandardButtons(QMessageBox::Yes | QMessageBox::Cancel);
+        box.setButtonText(QMessageBox::Yes, QStringLiteral("Delete"));
+        switch (box.exec()) {
+        case QMessageBox::Yes:
+            // delete the group from all uips that use it
+            for (int i = inUseIdx; i < presElems.count(); ++i) {
+                QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                        + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+                if (pPath != doc->GetDocumentPath())
+                    deleteGroupFromUip(pPath, group);
+            }
+            if (inUseIdx == 9999) {
+                // property has the deleted group, need to update it, else the deleted group
+                // will be saved the uip if the user saves the presentation.
+
+                // TODO: implement
+            }
+            break;
+
+        default:
+            // abort deletion
+            return;
+        }
+    }
+
+    // delete the group from current doc, if exists
+    deleteGroupFromUip(doc->GetDocumentPath(), group);
+
+    QDomElement variantsElem = domDoc.documentElement()
+                               .firstChildElement(QStringLiteral("variants"));
+    QDomNodeList groupsElems = variantsElem.elementsByTagName(QStringLiteral("variantgroup"));
+    // update and save the uia
+    bool deleted = false;
+    for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == group) {
+            variantsElem.removeChild(gElem);
+            StudioUtils::commitDomDocumentSave(file, domDoc);
+            deleted = true;
+            break;
+        }
+    }
+
+    // update m_variantsDef
+    for (auto &g : m_variantsDef) {
+        if (g.m_title == group) {
+            m_variantsDef.erase(&g);
+            break;
+        }
+    }
+}
+
+void ProjectFile::changeVariantGroupColor(const QString &group, const QString &newColor)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    // update and save the uia
+    QDomNodeList groupsElems = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"))
+                                     .elementsByTagName(QStringLiteral("variantgroup"));
+
+    for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == group) {
+            gElem.setAttribute(QStringLiteral("color"), newColor);
+            StudioUtils::commitDomDocumentSave(file, domDoc);
+            break;
+        }
+    }
+
+    // update m_variantsDef
+    for (auto &g : m_variantsDef) {
+        if (g.m_title == group) {
+            g.m_color = newColor;
+            break;
+        }
+    }
+}
+
+bool ProjectFile::tagExistsInUip(const QString &src, const QString &group, const QString &tag) const
+{
+    QFile file(src);
+    if (!file.open(QFile::Text | QFile::ReadOnly)) {
+        qWarning() << file.errorString();
+        return false;
+    }
+
+    QXmlStreamReader reader(&file);
+    reader.setNamespaceProcessing(false);
+
+    while (!reader.atEnd()) {
+        if (reader.readNextStartElement()) {
+            if (reader.name() == QLatin1String("Layer")
+                && reader.attributes().hasAttribute(QLatin1String("variants"))) {
+                QStringRef v = reader.attributes().value(QLatin1String("variants"));
+                if (v.contains(group + QLatin1Char(':') + tag))
+                    return true;
+            } else if (reader.name() == QLatin1String("Logic")) {
+                break;
+            }
+        }
+    }
+
+    return false;
+}
+
+bool ProjectFile::groupExistsInUip(const QString &src, const QString &group) const
+{
+    QFile file(src);
+    if (!file.open(QFile::Text | QFile::ReadOnly)) {
+        qWarning() << file.errorString();
+        return false;
+    }
+
+    QXmlStreamReader reader(&file);
+    reader.setNamespaceProcessing(false);
+
+    while (!reader.atEnd()) {
+        if (reader.readNextStartElement()) {
+            if (reader.name() == QLatin1String("Layer")
+                && reader.attributes().hasAttribute(QLatin1String("variants"))) {
+                QStringRef v = reader.attributes().value(QLatin1String("variants"));
+                if (v.contains(group + QLatin1Char(':')))
+                    return true;
+            } else if (reader.name() == QLatin1String("Logic")) {
+                break;
+            }
+        }
+    }
+
+    return false;
+}
+
+// renames a tag (if exists) in all layers in a uip file
+void ProjectFile::renameTagInUip(const QString &src, const QString &group, const QString &tag,
+                                 const QString &newName)
+{
+    QDomDocument domDoc;
+    QSaveFile file(src);
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomNodeList layerElems = domDoc.documentElement()
+                                    .elementsByTagName(QStringLiteral("Layer"));
+    bool needSave = false;
+    for (int i = 0; i < layerElems.count(); ++i) {
+        QDomElement lElem = layerElems.at(i).toElement();
+        if (lElem.hasAttribute(QStringLiteral("variants"))) {
+            QStringList tagPairs = lElem.attribute(QStringLiteral("variants"))
+                                   .split(QLatin1Char(','));
+            QString tagFrom = group + QLatin1Char(':') + tag;
+            QString tagTo = group + QLatin1Char(':') + newName;
+
+            if (tagPairs.contains(tagFrom)) {
+                tagPairs.replaceInStrings(tagFrom, tagTo);
+                lElem.setAttribute(QStringLiteral("variants"), tagPairs.join(QLatin1Char(',')));
+                needSave = true;
+            }
+        }
+    }
+
+    if (needSave)
+        StudioUtils::commitDomDocumentSave(file, domDoc);
+}
+
+void ProjectFile::renameGroupInUip(const QString &src, const QString &group, const QString &newName)
+{
+    QDomDocument domDoc;
+    QSaveFile file(src);
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomNodeList layerElems = domDoc.documentElement()
+                                    .elementsByTagName(QStringLiteral("Layer"));
+    bool needSave = false;
+    for (int i = 0; i < layerElems.count(); ++i) {
+        QDomElement lElem = layerElems.at(i).toElement();
+        if (lElem.hasAttribute(QStringLiteral("variants"))) {
+            QString variants = lElem.attribute(QStringLiteral("variants"));
+            if (variants.contains(group + QLatin1Char(':'))) {
+                variants.replace(group + QLatin1Char(':'), newName + QLatin1Char(':'));
+                lElem.setAttribute(QStringLiteral("variants"), variants);
+                needSave = true;
+            }
+        }
+    }
+
+    if (needSave)
+        StudioUtils::commitDomDocumentSave(file, domDoc);
+}
+
+// deletes a tag (if exists) from all layers in a uip file
+void ProjectFile::deleteTagFromUip(const QString &src, const QString &group, const QString &tag)
+{
+    QDomDocument domDoc;
+    QSaveFile file(src);
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomNodeList layerElems = domDoc.documentElement()
+                                    .elementsByTagName(QStringLiteral("Layer"));
+    bool needSave = false;
+    for (int i = 0; i < layerElems.count(); ++i) {
+        QDomElement lElem = layerElems.at(i).toElement();
+        if (lElem.hasAttribute(QStringLiteral("variants"))) {
+            QStringList tagPairs = lElem.attribute(QStringLiteral("variants"))
+                                                                        .split(QLatin1Char(','));
+            QString tagPair = group + QLatin1Char(':') + tag;
+            if (tagPairs.contains(tagPair)) {
+                tagPairs.removeOne(tagPair);
+                lElem.setAttribute(QStringLiteral("variants"), tagPairs.join(QLatin1Char(',')));
+                needSave = true;
+            }
+        }
+    }
+
+    if (needSave)
+        StudioUtils::commitDomDocumentSave(file, domDoc);
+}
+
+// deletes a group (if exists) from all layers in a uip file
+void ProjectFile::deleteGroupFromUip(const QString &src, const QString &group)
+{
+    QDomDocument domDoc;
+    QSaveFile file(src);
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    QDomNodeList layerElems = domDoc.documentElement()
+                                    .elementsByTagName(QStringLiteral("Layer"));
+    bool needSave = false;
+    QRegExp rgx(group + ":\\w*,|," + group + ":\\w*");
+    for (int i = 0; i < layerElems.count(); ++i) {
+        QDomElement lElem = layerElems.at(i).toElement();
+        if (lElem.hasAttribute(QStringLiteral("variants"))) {
+            QString val = lElem.attribute(QStringLiteral("variants"));
+            if (rgx.indexIn(val) != -1) {
+                val.replace(rgx, "");
+                lElem.setAttribute(QStringLiteral("variants"), val);
+                needSave = true;
+            }
+        }
+    }
+
+    if (needSave)
+        StudioUtils::commitDomDocumentSave(file, domDoc);
+}
+
+bool ProjectFile::isVariantGroupUnique(const QString &group) const
+{
+    for (auto &g : qAsConst(m_variantsDef)) {
+        if (g.m_title == group)
+            return false;
+    }
+
+    return true;
+}
+
+bool ProjectFile::isVariantTagUnique(const QString &group, const QString &tag) const
+{
+    for (auto &g : qAsConst(m_variantsDef)) {
+        if (g.m_title == group)
+            return !g.m_tags.contains(tag);
+    }
+
+    return true;
+}
+
+void ProjectFile::deleteVariantTag(const QString &group, const QString &tag)
+{
+    QDomDocument domDoc;
+    QSaveFile file(getProjectFilePath());
+    if (!StudioUtils::openDomDocumentSave(file, domDoc))
+        return;
+
+    // check if tag is in use in other presentations in the porject
+    int inUseIdx = -1; // list of presentations that has the tag in use
+    QDomNodeList presElems = domDoc.documentElement()
+                                   .firstChildElement(QStringLiteral("assets"))
+                                   .elementsByTagName(QStringLiteral("presentation"));
+    for (int i = 0; i < presElems.count(); ++i) {
+        QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+        if (pPath != g_StudioApp.GetCore()->GetDoc()->GetDocumentPath()
+                && tagExistsInUip(pPath, group, tag)) {
+            inUseIdx = i;
+            break;
+        }
+    }
+
+    if (inUseIdx != -1) {
+        QMessageBox box;
+        box.setWindowTitle(tr("Tag in use"));
+        box.setText(tr("The tag '%1' is in use in another presentation, are you sure you want to"
+                       " delete it?").arg(tag));
+        box.setIcon(QMessageBox::Warning);
+        box.setStandardButtons(QMessageBox::Yes | QMessageBox::Cancel);
+        box.setButtonText(QMessageBox::Yes, QStringLiteral("Delete"));
+        switch (box.exec()) {
+        case QMessageBox::Yes:
+            // delete the tag from all uips that use it
+            for (int i = inUseIdx; i < presElems.count(); ++i) {
+                QString pPath = m_fileInfo.path() + QLatin1Char('/')
+                        + presElems.at(i).toElement().attribute(QStringLiteral("src"));
+                if (pPath != g_StudioApp.GetCore()->GetDoc()->GetDocumentPath())
+                    deleteTagFromUip(pPath, group, tag);
+            }
+            break;
+
+        default:
+            // abort deletion
+            return;
+        }
+    }
+
+    // delete the tag from current doc, if exists
+    deleteTagFromUip(g_StudioApp.GetCore()->GetDoc()->GetDocumentPath(), group, tag);
+
+    QDomNodeList groupsElems = domDoc.documentElement()
+                                     .firstChildElement(QStringLiteral("variants"))
+                                     .elementsByTagName(QStringLiteral("variantgroup"));
+    // update and save the uia
+    bool deleted = false;
+     for (int i = 0; i < groupsElems.count(); ++i) {
+        QDomElement gElem = groupsElems.at(i).toElement();
+        if (gElem.attribute(QStringLiteral("id")) == group) {
+            QDomNodeList tagsElems = gElem.childNodes();
+            for (int j = 0; j < tagsElems.count(); ++j) {
+                QDomElement tElem = tagsElems.at(j).toElement();
+                if (tElem.attribute(QStringLiteral("id")) == tag) {
+                    gElem.removeChild(tElem);
+                    StudioUtils::commitDomDocumentSave(file, domDoc);
+                    deleted = true;
+                    break;
+                }
+            }
+            if (deleted)
+                break;
+        }
+    }
+
+    // update m_variantsDef
+    for (auto &g : m_variantsDef) {
+        if (g.m_title == group) {
+            g.m_tags.removeOne(tag);
+            break;
+        }
+    }
+}
diff --git a/src/Authoring/Studio/Application/ProjectFile.h b/src/Authoring/Studio/Application/ProjectFile.h
index 3e47da28..390ccb4c 100644
--- a/src/Authoring/Studio/Application/ProjectFile.h
+++ b/src/Authoring/Studio/Application/ProjectFile.h
@@ -46,6 +46,12 @@ class ProjectFile : public QObject
 public:
     ProjectFile();
 
+    struct VariantGroup {
+        QString m_title;
+        QString m_color;
+        QStringList m_tags;
+    };
+
     void create(const QString &uiaPath);
     void ensureProjectFile();
     void initProjectFile(const QString &presPath);
@@ -81,6 +87,19 @@ public:
     void deletePresentationFile(const QString &filePath);
     void renameMaterial(const QString &oldName, const QString &newName);
     bool duplicatePresentation(const QString &oldPres, const QString &newPres);
+    void loadVariants();
+    void addVariantTag(const QString &group, const QString &newTag);
+    void renameVariantTag(const QString &group, const QString &oldTag, const QString &newTag);
+    void deleteVariantTag(const QString &group, const QString &tag);
+    void addVariantGroup(const QString &newGroup);
+    void renameVariantGroup(const QString &oldGroup, const QString &newGroup);
+    void deleteVariantGroup(const QString &group);
+    void changeVariantGroupColor(const QString &group, const QString &newColor);
+    bool isVariantGroupUnique(const QString &group) const;
+    bool isVariantTagUnique(const QString &group, const QString &tag) const;
+
+    QVector<VariantGroup> variantsDef() const { return m_variantsDef; }
+
 
 Q_SIGNALS:
     void presentationIdChanged(const QString &path, const QString &id);
@@ -88,9 +107,17 @@ Q_SIGNALS:
 
 private:
     QString ensureUniquePresentationId(const QString &id) const;
+    bool tagExistsInUip(const QString &src, const QString &group, const QString &tag) const;
+    bool groupExistsInUip(const QString &src, const QString &group) const;
+    void deleteTagFromUip(const QString &src, const QString &group, const QString &tag);
+    void deleteGroupFromUip(const QString &src, const QString &group);
+    void renameTagInUip(const QString &src, const QString &group, const QString &tag,
+                        const QString &newName);
+    void renameGroupInUip(const QString &src, const QString &group, const QString &newName);
 
     QFileInfo m_fileInfo; // uia file info
     QString m_initialPresentation;
+    QVector<VariantGroup> m_variantsDef; // definition of variants
 };
 
 #endif // PROJECTFILE_H
diff --git a/src/Authoring/Studio/Application/StudioApp.cpp b/src/Authoring/Studio/Application/StudioApp.cpp
index 8b58e4f5..c86a5dba 100644
--- a/src/Authoring/Studio/Application/StudioApp.cpp
+++ b/src/Authoring/Studio/Application/StudioApp.cpp
@@ -1729,6 +1729,7 @@ bool CStudioApp::OnLoadDocument(const QString &inDocument, bool inShowStartupDia
         m_core->getProjectFile().updateDocPresentationId();
         m_core->getProjectFile().loadSubpresentationsAndDatainputs(m_subpresentations,
                                                                    m_dataInputDialogItems);
+        m_core->getProjectFile().loadVariants();
         getRenderer().RegisterSubpresentations(m_subpresentations);
 
         m_authorZoom = false;
diff --git a/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.cpp b/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.cpp
index d4fdc306..1232939c 100644
--- a/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.cpp
+++ b/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.cpp
@@ -62,6 +62,7 @@
 #include "foundation/Qt3DSLogging.h"
 #include "Dialogs.h"
 #include "Dispatch.h"
+#include "VariantsGroupModel.h"
 
 static QStringList renderableItems()
 {
@@ -107,8 +108,9 @@ static std::pair<bool, bool> getSlideCharacteristics(qt3dsdm::Qt3DSDMInstanceHan
     return std::make_pair(hasNextSlide, hasPreviousSlide);
 }
 
-InspectorControlModel::InspectorControlModel(QObject *parent)
-    : QAbstractListModel(parent)
+InspectorControlModel::InspectorControlModel(VariantsGroupModel *variantsModel, QObject *parent)
+    : m_variantsModel(variantsModel)
+    , QAbstractListModel(parent)
     , m_UpdatableEditor(*g_StudioApp.GetCore()->GetDoc())
 {
     m_modifiedProperty.first = 0;
@@ -1229,7 +1231,6 @@ void InspectorControlModel::updatePropertyValue(InspectorControlBase *element) c
                     metaDataProvider->GetMetaDataProperty(instance, element->m_property));
     }
 
-
     bool skipEmits = false;
     switch (element->m_dataType) {
     case qt3dsdm::DataModelDataType::String: {
@@ -1239,6 +1240,10 @@ void InspectorControlModel::updatePropertyValue(InspectorControlBase *element) c
             if (index != -1)
                 stringValue = stringValue.mid(index + 1);
         }
+
+        if (bridge->IsLayerInstance(instance))
+            m_variantsModel->refresh();
+
         element->m_value = stringValue;
     } // intentional fall-through for other String-derived datatypes
     case qt3dsdm::DataModelDataType::StringOrInt:
diff --git a/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.h b/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.h
index e329dba1..21e6b3a7 100644
--- a/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.h
+++ b/src/Authoring/Studio/Palettes/Inspector/InspectorControlModel.h
@@ -42,6 +42,7 @@
 class CInspectableBase;
 class Qt3DSDMInspectable;
 class SGuideInspectableImpl;
+class VariantsGroupModel;
 
 namespace qt3dsdm {
 class ISignalConnection;
@@ -107,7 +108,7 @@ class InspectorControlModel : public QAbstractListModel
 {
     Q_OBJECT
 public:
-    explicit InspectorControlModel(QObject *parent);
+    explicit InspectorControlModel(VariantsGroupModel *variantsModel, QObject *parent);
     ~InspectorControlModel() = default;
 
     enum Roles {
@@ -247,6 +248,8 @@ private:
     bool isGroupRebuildRequired(CInspectableBase *inspectable, int theIndex) const;
 
     static int handleToGuidePropIndex(int handle) { return handle - 1; }
+
+    VariantsGroupModel *m_variantsModel = nullptr;
 };
 
 #endif // INSPECTORCONTROLMODEL_H
diff --git a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.cpp b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.cpp
index 69543a12..6252c0ea 100644
--- a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.cpp
+++ b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.cpp
@@ -58,6 +58,8 @@
 #include "MaterialRefView.h"
 #include "BasicObjectsModel.h"
 #include "Qt3DSDMSlides.h"
+#include "VariantsGroupModel.h"
+#include "VariantTagDialog.h"
 
 #include <QtCore/qtimer.h>
 #include <QtQml/qqmlcontext.h>
@@ -69,7 +71,8 @@
 InspectorControlView::InspectorControlView(const QSize &preferredSize, QWidget *parent)
     : QQuickWidget(parent),
       TabNavigable(),
-      m_inspectorControlModel(new InspectorControlModel(this)),
+      m_variantsGroupModel(new VariantsGroupModel(this)),
+      m_inspectorControlModel(new InspectorControlModel(m_variantsGroupModel, this)),
       m_meshChooserView(new MeshChooserView(this)),
       m_instance(0),
       m_handle(0),
@@ -241,6 +244,7 @@ void InspectorControlView::initialize()
     CStudioPreferences::setQmlContextProperties(rootContext());
     rootContext()->setContextProperty(QStringLiteral("_parentView"), this);
     rootContext()->setContextProperty(QStringLiteral("_inspectorModel"), m_inspectorControlModel);
+    rootContext()->setContextProperty(QStringLiteral("_variantsGroupModel"), m_variantsGroupModel);
     rootContext()->setContextProperty(QStringLiteral("_resDir"), StudioUtils::resourceImageUrl());
     rootContext()->setContextProperty(QStringLiteral("_tabOrderHandler"), tabOrderHandler());
     rootContext()->setContextProperty(QStringLiteral("_mouseHelper"), &m_mouseHelper);
@@ -412,6 +416,8 @@ void InspectorControlView::setInspectable(CInspectableBase *inInspectable)
         m_inspectorControlModel->setInspectable(inInspectable);
 
         Q_EMIT titleChanged();
+
+        m_variantsGroupModel->refresh();
     }
 }
 
@@ -452,6 +458,62 @@ void InspectorControlView::showContextMenu(int x, int y, int handle, int instanc
     m_handle = 0;
 }
 
+void InspectorControlView::showTagContextMenu(int x, int y, const QString &group,
+                                              const QString &tag)
+{
+    QMenu theContextMenu;
+
+    auto actionRename = theContextMenu.addAction(QObject::tr("Rename Tag"));
+    connect(actionRename, &QAction::triggered, this, [&]() {
+        VariantTagDialog dlg(VariantTagDialog::RenameTag, group, tag);
+        if (dlg.exec() == QDialog::Accepted) {
+            g_StudioApp.GetCore()->getProjectFile().renameVariantTag(group, dlg.getNames().first,
+                                                                     dlg.getNames().second);
+        }
+    });
+
+    auto actionDelete = theContextMenu.addAction(QObject::tr("Delete Tag"));
+    connect(actionDelete, &QAction::triggered, this, [&]() {
+        g_StudioApp.GetCore()->getProjectFile().deleteVariantTag(group, tag);
+    });
+
+    theContextMenu.exec(mapToGlobal({x, y}));
+}
+
+void InspectorControlView::showGroupContextMenu(int x, int y, const QString &group)
+{
+    QMenu theContextMenu;
+
+    ProjectFile &projectFile = g_StudioApp.GetCore()->getProjectFile();
+
+    auto actionRename = theContextMenu.addAction(QObject::tr("Rename Group"));
+    connect(actionRename, &QAction::triggered, this, [&]() {
+        VariantTagDialog dlg(VariantTagDialog::RenameGroup, {}, group);
+        if (dlg.exec() == QDialog::Accepted) {
+            projectFile.renameVariantGroup(dlg.getNames().first, dlg.getNames().second);
+        }
+    });
+
+    auto actionColor = theContextMenu.addAction(QObject::tr("Change Group Color"));
+    connect(actionColor, &QAction::triggered, this, [&]() {
+        const auto variantsDef = g_StudioApp.GetCore()->getProjectFile().variantsDef();
+        for (auto &g : variantsDef) {
+            if (g.m_title == group) {
+                QColor newColor = this->showColorDialog(g.m_color);
+                projectFile.changeVariantGroupColor(group, newColor.name());
+                break;
+            }
+        }
+    });
+
+    auto actionDelete = theContextMenu.addAction(QObject::tr("Delete Group"));
+    connect(actionDelete, &QAction::triggered, this, [&]() {
+        projectFile.deleteVariantGroup(group);
+    });
+
+    theContextMenu.exec(mapToGlobal({x, y}));
+}
+
 void InspectorControlView::toggleMasterLink()
 {
     Q3DStudio::ScopedDocumentEditor editor(*g_StudioApp.GetCore()->GetDoc(),
diff --git a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.h b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.h
index 98d67f41..14936b57 100644
--- a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.h
+++ b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.h
@@ -39,6 +39,7 @@
 #include "DataInputSelectView.h"
 
 class InspectorControlModel;
+class VariantsGroupModel;
 class CInspectableBase;
 class ImageChooserView;
 class DataInputSelectView;
@@ -72,6 +73,8 @@ public:
     QString titleIcon() const;
 
     Q_INVOKABLE void showContextMenu(int x, int y, int handle, int instance);
+    Q_INVOKABLE void showTagContextMenu(int x, int y, const QString &group, const QString &tag);
+    Q_INVOKABLE void showGroupContextMenu(int x, int y, const QString &group);
     Q_INVOKABLE QObject *showImageChooser(int handle, int instance, const QPoint &point);
     Q_INVOKABLE QObject *showFilesChooser(int handle, int instance, const QPoint &point);
     Q_INVOKABLE QObject *showMeshChooser(int handle, int instance, const QPoint &point);
@@ -126,6 +129,7 @@ private:
 
     std::vector<std::shared_ptr<qt3dsdm::ISignalConnection>> m_connections;
     QColor m_backgroundColor;
+    VariantsGroupModel *m_variantsGroupModel = nullptr;
     InspectorControlModel *m_inspectorControlModel = nullptr;
     CInspectableBase *m_inspectableBase = nullptr;
     QPointer<ImageChooserView> m_imageChooserView;
diff --git a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.qml b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.qml
index b2e8b286..833bbd65 100644
--- a/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.qml
+++ b/src/Authoring/Studio/Palettes/Inspector/InspectorControlView.qml
@@ -28,6 +28,8 @@
 import QtQuick 2.8
 import QtQuick.Layouts 1.1
 import QtQuick.Controls 2.2
+import QtQuick.Controls.Styles 1.4
+import QtQuick.Extras 1.4
 
 import Qt3DStudio 1.0
 import "../controls"
@@ -286,6 +288,7 @@ Rectangle {
 
                                 ColumnLayout { // Property row and datainput control
                                     Layout.alignment: Qt.AlignTop
+                                    visible: modelData.title !== "variants"
                                     spacing: 0
                                     RowLayout { // Property row
                                         Layout.alignment: Qt.AlignLeft
@@ -315,7 +318,7 @@ Rectangle {
                                                     anchors.fill: parent
                                                     acceptedButtons: Qt.RightButton | Qt.LeftButton
                                                     hoverEnabled: true
-                                                    onClicked:  {
+                                                    onClicked: {
                                                         if (mouse.button === Qt.LeftButton) {
                                                             _inspectorModel.setPropertyAnimated(
                                                                         model.modelData.instance,
@@ -423,6 +426,9 @@ Rectangle {
                                     opacity: enabled ? 1 : .5
                                     Layout.alignment: Qt.AlignTop
                                     sourceComponent: {
+                                        if (modelData.title === "variants")
+                                            return variantTagsComponent;
+
                                         const dataType = modelData.dataType;
                                         switch (dataType) {
                                         case DataModelDataType.Long:
@@ -1098,4 +1104,154 @@ Rectangle {
             }
         }
     }
+
+    Component {
+        id: variantTagsComponent
+
+        Column {
+            width: root.width - 10
+            spacing: 10
+
+            Row {
+                anchors.right: parent.right
+                anchors.rightMargin: 5
+                spacing: 5
+
+                ToolButton {
+                    id: importButton
+                    text: qsTr("Import...")
+                    width: 70
+                    height: 20
+
+                    onClicked: {
+                        // TODO: implement
+                    }
+                }
+
+                ToolButton {
+                    id: exportButton
+                    text: qsTr("Export...")
+                    width: 70
+                    height: 20
+
+                    onClicked: {
+                        // TODO: implement
+                    }
+                }
+            }
+
+            Text {
+                text: qsTr("There are no variant tags yet. Click [+ Group] to add a new tag group and start adding tags.")
+                color: "#ffffff"
+                visible: _variantsGroupModel.rowCount() === 0
+            }
+
+            Repeater {
+                id: tagsReeater
+                model: _variantsGroupModel
+
+                Row {
+                    id: variantTagsRow
+
+                    readonly property var tagsModel: model.tags
+                    readonly property var groupModel: model
+
+                    Text {
+                        text: model.group
+                        color: model.color
+                        width: 50
+                        anchors.top: parent.top
+                        anchors.topMargin: 5
+
+                        MouseArea {
+                            anchors.fill: parent;
+                            acceptedButtons: Qt.RightButton
+                            onClicked: {
+                                if (mouse.button === Qt.RightButton) {
+                                    const coords = mapToItem(root, mouse.x, mouse.y);
+                                    _parentView.showGroupContextMenu(coords.x, coords.y, model.group);
+                                }
+                            }
+                        }
+                    }
+
+                    Flow {
+                        width: root.width - 110
+                        spacing: 5
+
+                        Repeater {
+                            model: tagsModel
+
+                            Loader {
+                                readonly property var tagsModel: model
+                                readonly property var grpModel: groupModel
+                                sourceComponent: tagComponent
+                            }
+                        }
+
+                        ToolButton {
+                            id: addTagButton
+                            text: qsTr("+ Tag")
+                            height: 25
+
+                            onClicked: {
+                                _variantsGroupModel.addNewTag(groupModel.group)
+                            }
+
+                        }
+                    }
+                }
+            }
+
+            Item { width: 1; height: 5 } // vertical spacer
+
+            ToolButton {
+                id: addGroupButton
+                text: qsTr("+ Group")
+                width: 60
+                height: 25
+                onClicked: {
+                    _variantsGroupModel.addNewGroup()
+                }
+            }
+
+            Item { width: 1; height: 5 } // vertical spacer
+        }
+    }
+
+    Component {
+        id: tagComponent
+
+        Rectangle {
+            property bool toggled: tagsModel.selected
+            property string grpColor: grpModel ? grpModel.color : ""
+
+            width: Math.max(tLabel.width + 10, 60)
+            height: 25
+            color: toggled ? grpColor : "#2e2f30"
+            border.color: "#959596"
+
+            Text {
+                id: tLabel
+                anchors.centerIn: parent
+                text: tagsModel.tag
+                color: toggled ? "#ffffff" : "#959596"
+            }
+
+            MouseArea {
+                anchors.fill: parent;
+                acceptedButtons: Qt.RightButton | Qt.LeftButton
+                onClicked: {
+                    if (mouse.button === Qt.LeftButton) {
+                        toggled = !toggled;
+                        _variantsGroupModel.setTagState(grpModel.group, tagsModel.tag, toggled);
+                    } else if (mouse.button === Qt.RightButton) {
+                        const coords = mapToItem(root, mouse.x, mouse.y);
+                        _parentView.showTagContextMenu(coords.x, coords.y, grpModel.group,
+                                                       tagsModel.tag);
+                    }
+                }
+            }
+        }
+    }
 }
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.cpp b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.cpp
new file mode 100644
index 00000000..83e72e7b
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.cpp
@@ -0,0 +1,106 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "VariantTagDialog.h"
+#include "ui_VariantTagDialog.h"
+#include "Dialogs.h"
+#include "StudioApp.h"
+#include "Core.h"
+#include "ProjectFile.h"
+
+VariantTagDialog::VariantTagDialog(DialogType type, const QString &group, const QString &name,
+                                   QWidget *parent)
+    : QDialog(parent)
+    , m_type(type)
+    , m_group(group)
+    , m_ui(new Ui::VariantTagDialog)
+{
+    m_ui->setupUi(this);
+
+    m_names.first = name;
+
+    if (type == AddGroup) {
+        setWindowTitle(tr("Add new Group"));
+        m_ui->label->setText(tr("Group name"));
+    } else if (type == RenameGroup) {
+        setWindowTitle(tr("Rename Group"));
+        m_ui->label->setText(tr("Group name"));
+        m_ui->lineEditTagName->setText(name);
+        m_ui->lineEditTagName->selectAll();
+    } else if (type == RenameTag) {
+        m_ui->lineEditTagName->setText(name);
+        m_ui->lineEditTagName->selectAll();
+    }
+}
+
+void VariantTagDialog::accept()
+{
+    QString name = m_ui->lineEditTagName->text();
+
+    if (name.isEmpty()) {
+        displayWarning(EmptyWarning);
+    } else if (name == m_names.first) { // no change
+        QDialog::reject();
+    } else if (((m_type == AddGroup || m_type == RenameGroup)
+                && !g_StudioApp.GetCore()->getProjectFile().isVariantGroupUnique(name))
+               || (!g_StudioApp.GetCore()->getProjectFile().isVariantTagUnique(m_group, name))) {
+        displayWarning(UniqueWarning);
+    } else {
+        m_names.second = name;
+        QDialog::accept();
+    }
+}
+
+std::pair<QString, QString> VariantTagDialog::getNames() const
+{
+    return m_names;
+}
+
+void VariantTagDialog::displayWarning(WarningType warningType)
+{
+    QString warning;
+    if (warningType == EmptyWarning) {
+        if (m_type == AddGroup || m_type == RenameGroup)
+            warning = tr("The group name must not be empty.");
+        else
+            warning = tr("The tag name must not be empty.");
+    } else if (warningType == UniqueWarning) {
+        if (m_type == AddGroup || m_type == RenameGroup)
+            warning = tr("The group name must be unique.");
+        else
+            warning = tr("The tag name must be unique within the tag group.");
+    }
+
+    g_StudioApp.GetDialogs()->DisplayMessageBox(tr("Warning"), warning,
+                                                Qt3DSMessageBox::ICON_WARNING, false);
+}
+
+VariantTagDialog::~VariantTagDialog()
+{
+    delete m_ui;
+}
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.h b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.h
new file mode 100644
index 00000000..b5e3989f
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.h
@@ -0,0 +1,73 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef VARIANTTAGDIALOG_H
+#define VARIANTTAGDIALOG_H
+
+#include <QtWidgets/qdialog.h>
+
+#ifdef QT_NAMESPACE
+using namespace QT_NAMESPACE;
+#endif
+
+QT_BEGIN_NAMESPACE
+namespace Ui {
+class VariantTagDialog;
+}
+QT_END_NAMESPACE
+
+class VariantTagDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    enum DialogType { AddTag, RenameTag, AddGroup, RenameGroup };
+
+    explicit VariantTagDialog(DialogType type, const QString &group = {}, const QString &name = {},
+                              QWidget *parent = nullptr);
+    ~VariantTagDialog() override;
+
+public Q_SLOTS:
+    void accept() override;
+    std::pair<QString, QString> getNames() const;
+
+private:
+    enum WarningType {
+        EmptyWarning,
+        UniqueWarning
+    };
+
+    void displayWarning(WarningType warningType);
+
+    DialogType m_type;
+    QString m_group;
+    Ui::VariantTagDialog *m_ui;
+    std::pair<QString, QString> m_names; // holds the tags values before and after rename
+};
+
+#endif // VARIANTTAGDIALOG_H
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.ui b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.ui
new file mode 100644
index 00000000..aa5d24ef
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantTagDialog.ui
@@ -0,0 +1,113 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>VariantTagDialog</class>
+ <widget class="QDialog" name="VariantTagDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>241</width>
+    <height>89</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Add new Tag</string>
+  </property>
+  <property name="sizeGripEnabled">
+   <bool>false</bool>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="leftMargin">
+    <number>0</number>
+   </property>
+   <property name="topMargin">
+    <number>0</number>
+   </property>
+   <property name="rightMargin">
+    <number>0</number>
+   </property>
+   <property name="bottomMargin">
+    <number>0</number>
+   </property>
+   <item>
+    <widget class="QWidget" name="widget" native="true">
+     <layout class="QVBoxLayout" name="verticalLayout_2">
+      <item>
+       <widget class="QWidget" name="labelEditLayout" native="true">
+        <layout class="QHBoxLayout" name="horizontalLayout" stretch="0">
+         <property name="leftMargin">
+          <number>0</number>
+         </property>
+         <property name="topMargin">
+          <number>0</number>
+         </property>
+         <property name="rightMargin">
+          <number>0</number>
+         </property>
+         <property name="bottomMargin">
+          <number>0</number>
+         </property>
+         <item>
+          <widget class="QLabel" name="label">
+           <property name="text">
+            <string>Tag name</string>
+           </property>
+          </widget>
+         </item>
+        </layout>
+       </widget>
+      </item>
+      <item>
+       <widget class="QLineEdit" name="lineEditTagName"/>
+      </item>
+      <item>
+       <widget class="QDialogButtonBox" name="buttonBox">
+        <property name="orientation">
+         <enum>Qt::Horizontal</enum>
+        </property>
+        <property name="standardButtons">
+         <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>VariantTagDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>VariantTagDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.cpp b/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.cpp
new file mode 100644
index 00000000..3a2a2a45
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.cpp
@@ -0,0 +1,181 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "VariantsGroupModel.h"
+#include "VariantsTagModel.h"
+#include "StudioApp.h"
+#include "Core.h"
+#include "QDebug" // TODO: remove
+#include "Qt3DSDMStudioSystem.h"
+#include "ClientDataModelBridge.h"
+#include "IDocumentEditor.h"
+#include "VariantTagDialog.h"
+
+VariantsGroupModel::VariantsGroupModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+
+}
+
+void VariantsGroupModel::refresh()
+{
+    int instance = g_StudioApp.GetCore()->GetDoc()->GetSelectedInstance();
+    auto bridge = g_StudioApp.GetCore()->GetDoc()->GetStudioSystem()->GetClientDataModelBridge();
+
+    if (instance == 0 || !bridge->IsLayerInstance(instance)) {
+        m_instance = 0;
+        m_property = 0;
+        return;
+    }
+
+    auto propertySystem = g_StudioApp.GetCore()->GetDoc()->GetStudioSystem()->GetPropertySystem();
+    m_instance = instance;
+    m_property = propertySystem->GetAggregateInstancePropertyByName(instance, L"variants");
+
+    qt3dsdm::SValue sValue;
+    if (propertySystem->GetInstancePropertyValue(m_instance, m_property, sValue)) {
+        beginResetModel();
+        m_data.clear();
+
+        QString val = QString::fromWCharArray(
+                      qt3dsdm::get<qt3dsdm::TDataStrPtr>(sValue)->GetData());
+        // TODO: remove qDebug when the variants work is fully done.
+        qDebug() << "\x1b[42m \x1b[1m" << __FUNCTION__
+                 << ", val=" << val
+                 << "\x1b[m";
+        QHash<QString, QStringList> propTags;
+        if (!val.isEmpty()) {
+            const QStringList propTagsList = val.split(QChar(','));
+            for (auto &propTag : propTagsList) {
+                const QStringList propTagPair = propTag.split(QChar(':'));
+                propTags[propTagPair[0]].append(propTagPair[1]);
+            }
+        }
+
+        // build the variants data model
+        const auto variantsDef = g_StudioApp.GetCore()->getProjectFile().variantsDef();
+        for (auto &group : variantsDef) {
+            TagGroupData g;
+            g.m_title = group.m_title;
+            g.m_color = group.m_color;
+
+            VariantsTagModel *m = new VariantsTagModel(this);
+            QVector<std::pair<QString, bool> > tags;
+            for (int i = 0; i < group.m_tags.length(); ++i)
+                tags.append({group.m_tags[i], propTags[group.m_title].contains(group.m_tags[i])});
+
+            m->init(tags);
+            g.m_tagsModel = m;
+
+            m_data.push_back(g);
+        }
+
+        endResetModel();
+    }
+}
+
+int VariantsGroupModel::rowCount(const QModelIndex &parent) const
+{
+    // For list models only the root node (an invalid parent) should return the list's size. For all
+    // other (valid) parents, rowCount() should return 0 so that it does not become a tree model.
+    if (parent.isValid())
+        return 0;
+
+    return m_data.size();
+}
+
+QVariant VariantsGroupModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid())
+        return QVariant();
+
+    if (role == GroupTitleRole)
+        return m_data.at(index.row()).m_title;
+    else if (role == GroupColorRole)
+        return m_data.at(index.row()).m_color;
+    else if (role == TagRole)
+        return QVariant::fromValue(m_data.at(index.row()).m_tagsModel);
+
+    return QVariant();
+}
+
+void VariantsGroupModel::setTagState(const QString &group, const QString &tag, bool selected)
+{
+    QString val;
+    QString tagsStr;
+    bool skipFirst = false;
+    for (auto &g : qAsConst(m_data)) {
+        if (g.m_title == group)
+            g.m_tagsModel->updateTagState(tag, selected);
+
+        tagsStr = g.m_tagsModel->serialize(g.m_title);
+        if (!tagsStr.isEmpty()) {
+            if (skipFirst)
+                val.append(QChar(','));
+            val.append(tagsStr);
+            skipFirst = true;
+        }
+    }
+
+    auto sVal = std::make_shared<qt3dsdm::CDataStr>(Q3DStudio::CString::fromQString(val));
+    Q3DStudio::SCOPED_DOCUMENT_EDITOR(*g_StudioApp.GetCore()->GetDoc(), QObject::tr("Set Property"))
+            ->SetInstancePropertyValue(m_instance, m_property, sVal);
+}
+
+void VariantsGroupModel::addNewTag(const QString &group)
+{
+    VariantTagDialog dlg(VariantTagDialog::AddTag, group);
+
+    if (dlg.exec() == QDialog::Accepted)
+        g_StudioApp.GetCore()->getProjectFile().addVariantTag(group, dlg.getNames().second);
+}
+
+void VariantsGroupModel::addNewGroup()
+{
+    VariantTagDialog dlg(VariantTagDialog::AddGroup);
+
+    if (dlg.exec() == QDialog::Accepted)
+        g_StudioApp.GetCore()->getProjectFile().addVariantGroup(dlg.getNames().second);
+}
+
+QHash<int, QByteArray> VariantsGroupModel::roleNames() const
+{
+    auto names = QAbstractListModel::roleNames();
+    names.insert(GroupTitleRole, "group");
+    names.insert(GroupColorRole, "color");
+    names.insert(TagRole, "tags");
+    return names;
+}
+
+Qt::ItemFlags VariantsGroupModel::flags(const QModelIndex &index) const
+{
+    if (!index.isValid())
+        return Qt::NoItemFlags;
+
+    return Qt::ItemIsEditable;
+}
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.h b/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.h
new file mode 100644
index 00000000..695e3fb0
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantsGroupModel.h
@@ -0,0 +1,77 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef VARIANTSGROUPMODEL_H
+#define VARIANTSGROUPMODEL_H
+
+#include <QtCore/qabstractitemmodel.h>
+
+class VariantsTagModel;
+
+class VariantsGroupModel : public QAbstractListModel
+{
+    Q_OBJECT
+
+public:
+    explicit VariantsGroupModel(QObject *parent = nullptr);
+
+    enum Roles {
+        GroupTitleRole = Qt::UserRole + 1,
+        GroupColorRole,
+        TagRole
+    };
+
+    struct TagGroupData
+    {
+        QString m_title;
+        QString m_color;
+        VariantsTagModel *m_tagsModel = nullptr;
+    };
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = GroupTitleRole) const override;
+
+    Qt::ItemFlags flags(const QModelIndex& index) const override;
+
+    void refresh();
+
+    Q_INVOKABLE void setTagState(const QString &group, const QString &tag, bool selected);
+    Q_INVOKABLE void addNewTag(const QString &group);
+    Q_INVOKABLE void addNewGroup();
+
+
+protected:
+      QHash<int, QByteArray> roleNames() const override;
+
+private:
+      QVector<TagGroupData> m_data;
+      int m_instance = 0; // selected layer instance
+      int m_property = 0; // variant tags property handler
+};
+
+#endif // VARIANTSGROUPMODEL_H
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.cpp b/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.cpp
new file mode 100644
index 00000000..910b4f09
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.cpp
@@ -0,0 +1,108 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "VariantsTagModel.h"
+
+VariantsTagModel::VariantsTagModel(QObject *parent)
+    : QAbstractListModel(parent)
+{
+
+}
+
+void VariantsTagModel::init(const QVector<std::pair<QString, bool> > &data)
+{
+    m_data = data;
+}
+
+void VariantsTagModel::updateTagState(const QString &tag, bool selected)
+{
+    for (auto &t : m_data) {
+        if (t.first == tag) {
+            t.second = selected;
+            break;
+        }
+    }
+}
+
+// return the tags in a formatted string to be saved to the property
+QString VariantsTagModel::serialize(const QString &groupName) const
+{
+    QString ret;
+    bool skipFirst = false;
+    for (auto &t : qAsConst(m_data)) {
+        if (t.second) {
+            if (skipFirst)
+                ret.append(QLatin1Char(','));
+
+            ret.append(groupName + QLatin1Char(':') + t.first);
+
+            skipFirst = true;
+        }
+    }
+
+    return ret;
+}
+
+int VariantsTagModel::rowCount(const QModelIndex &parent) const
+{
+    // For list models only the root node (an invalid parent) should return the list's size. For all
+    // other (valid) parents, rowCount() should return 0 so that it does not become a tree model.
+    if (parent.isValid())
+        return 0;
+
+    return m_data.size();
+}
+
+QVariant VariantsTagModel::data(const QModelIndex &index, int role) const
+{
+    if (!index.isValid())
+        return QVariant();
+
+    if (role == TagRole)
+        return m_data.at(index.row()).first;
+    else if (role == SelectedRole)
+        return m_data.at(index.row()).second;
+
+    return QVariant();
+}
+
+QHash<int, QByteArray> VariantsTagModel::roleNames() const
+{
+    auto names = QAbstractListModel::roleNames();
+    names.insert(TagRole, "tag");
+    names.insert(SelectedRole, "selected");
+    return names;
+}
+
+Qt::ItemFlags VariantsTagModel::flags(const QModelIndex &index) const
+{
+    if (!index.isValid())
+        return Qt::NoItemFlags;
+
+    return Qt::ItemIsEditable; // FIXME: Implement me!
+}
diff --git a/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.h b/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.h
new file mode 100644
index 00000000..01bb4e73
--- /dev/null
+++ b/src/Authoring/Studio/Palettes/Inspector/VariantsTagModel.h
@@ -0,0 +1,62 @@
+/****************************************************************************
+**
+** Copyright (C) 2019 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef VARIANTSTAGMODEL_H
+#define VARIANTSTAGMODEL_H
+
+#include <QtCore/qabstractitemmodel.h>
+
+class VariantsTagModel : public QAbstractListModel
+{
+    Q_OBJECT
+
+public:
+    explicit VariantsTagModel(QObject *parent = nullptr);
+
+    enum Roles {
+        TagRole = Qt::UserRole + 1,
+        SelectedRole,
+    };
+
+    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
+    QVariant data(const QModelIndex &index, int role = TagRole) const override;
+
+    Qt::ItemFlags flags(const QModelIndex& index) const override;
+
+    void init(const QVector<std::pair<QString, bool> > &data);
+    void updateTagState(const QString &tag, bool selected);
+    QString serialize(const QString &groupName) const;
+
+protected:
+      QHash<int, QByteArray> roleNames() const override;
+
+private:
+      QVector<std::pair<QString, bool> > m_data; // [{tagName, selectedState}, ...]
+};
+
+#endif // VARIANTSTAGMODEL_H
diff --git a/src/Authoring/Studio/Qt3DStudio.pro b/src/Authoring/Studio/Qt3DStudio.pro
index bd251740..86103a2c 100644
--- a/src/Authoring/Studio/Qt3DStudio.pro
+++ b/src/Authoring/Studio/Qt3DStudio.pro
@@ -226,7 +226,10 @@ HEADERS += \
     Palettes/scenecamera/scenecameraview.h \
     Palettes/scenecamera/scenecamerascrollarea.h \
     Palettes/scenecamera/scenecameraglwidget.h \
-    Palettes/TimelineGraphicsView/ui/RowTimelineCommentItem.h
+    Palettes/TimelineGraphicsView/ui/RowTimelineCommentItem.h \
+    Palettes/Inspector/VariantsGroupModel.h \
+    Palettes/Inspector/VariantsTagModel.h \
+    Palettes/Inspector/VariantTagDialog.h
 
 FORMS += \
     MainFrm.ui \
@@ -246,7 +249,8 @@ FORMS += \
     UI/StartupDlg.ui \
     Palettes/Project/EditPresentationIdDlg.ui \
     Palettes/Project/ChooseImagePropertyDlg.ui \
-    Palettes/scenecamera/scenecameraview.ui
+    Palettes/scenecamera/scenecameraview.ui \
+    Palettes/Inspector/VariantTagDialog.ui
 
 SOURCES += \
     Application/AboutDlg.cpp \
@@ -402,7 +406,10 @@ SOURCES += \
     Palettes/scenecamera/scenecameraview.cpp \
     Palettes/scenecamera/scenecamerascrollarea.cpp \
     Palettes/scenecamera/scenecameraglwidget.cpp \
-    Palettes/TimelineGraphicsView/ui/RowTimelineCommentItem.cpp
+    Palettes/TimelineGraphicsView/ui/RowTimelineCommentItem.cpp \
+    Palettes/Inspector/VariantsGroupModel.cpp \
+    Palettes/Inspector/VariantsTagModel.cpp \
+    Palettes/Inspector/VariantTagDialog.cpp
 
 RESOURCES += \
     MainFrm.qrc \
diff --git a/src/Runtime/res/DataModelMetadata/en-us/MetaData.xml b/src/Runtime/res/DataModelMetadata/en-us/MetaData.xml
index b376d272..534b4c17 100644
--- a/src/Runtime/res/DataModelMetadata/en-us/MetaData.xml
+++ b/src/Runtime/res/DataModelMetadata/en-us/MetaData.xml
@@ -94,6 +94,9 @@
                 <Property name="blendtype" formalName="Blend Mode" list="Normal:Screen:Multiply:Add:Subtract:*Overlay:*ColorBurn:*ColorDodge" default="Normal" description="Mode of blending between this layer\nand layers below. Modes marked with\n* are available only with HW supporting\nadvanced blending modes." category="Basic Properties" />
                 <Property name="sourcepath" formalName="Sub-Presentation" description="Presentation or QML stream to\nrender for this layer" type="Renderable" controllable="True"  category="Basic Properties" />
 
+                <!-- Variant Tags -->
+                <Property name="variants" type="String" category="Variant Tags" />
+
                 <!-- Antialiasing -->
                 <Property name="progressiveaa" formalName="Progressive AA" description="Improves the visual quality when no\nitems are moving" list="None:2x:4x:8x" default="None" category="Antialiasing" />
                 <Property name="multisampleaa" formalName="Multisample AA" description="Improves geometry quality, e.g.\nsilhouettes." list="None:2x:4x:SSAA" default="None" category="Antialiasing" />