diff --git a/src/App/ComplexGeoData.cpp b/src/App/ComplexGeoData.cpp
index 32ece65915..8cd035e829 100644
--- a/src/App/ComplexGeoData.cpp
+++ b/src/App/ComplexGeoData.cpp
@@ -184,6 +184,11 @@ bool ComplexGeoData::getCenterOfGravity(Base::Vector3d& unused) const
     return false;
 }
 
+const std::string &ComplexGeoData::elementMapPrefix() {
+    static std::string prefix(";");
+    return prefix;
+}
+
 size_t ComplexGeoData::getElementMapSize(bool flush) const
 {
     if (flush) {
@@ -621,6 +626,25 @@ unsigned int ComplexGeoData::getMemSize() const
     return 0;
 }
 
+
+void ComplexGeoData::setMappedChildElements(const std::vector<Data::ElementMap::MappedChildElements> & children)
+{
+    // DO NOT reset element map if there is one. Because we allow mixing child
+    // mapping and normal mapping
+    if (!_elementMap) {
+        resetElementMap(std::make_shared<Data::ElementMap>());
+    }
+    _elementMap->addChildElements(Tag, children);
+}
+
+std::vector<Data::ElementMap::MappedChildElements> ComplexGeoData::getMappedChildElements() const
+{
+    if (!_elementMap) {
+        return {};
+    }
+    return _elementMap->getChildElements();
+}
+
 void ComplexGeoData::beforeSave() const
 {
     flushElementMap();
diff --git a/src/App/ComplexGeoData.h b/src/App/ComplexGeoData.h
index 8364dde4cd..7bf68b3bea 100644
--- a/src/App/ComplexGeoData.h
+++ b/src/App/ComplexGeoData.h
@@ -176,6 +176,7 @@ public:
     virtual bool getCenterOfGravity(Base::Vector3d& center) const;
     //@}
 
+    static const std::string &elementMapPrefix();
 
     /** @name Element name mapping */
     //@{
@@ -247,6 +248,9 @@ public:
 
     // NOTE: getElementHistory is now in ElementMap
 
+    void setMappedChildElements(const std::vector<Data::ElementMap::MappedChildElements> & children);
+    std::vector<Data::ElementMap::MappedChildElements> getMappedChildElements() const;
+
     char elementType(const Data::MappedName &) const;
     char elementType(const Data::IndexedName &) const;
     char elementType(const char *name) const;
diff --git a/tests/src/Mod/Part/App/TopoShapeExpansion.cpp b/tests/src/Mod/Part/App/TopoShapeExpansion.cpp
new file mode 100644
index 0000000000..702f97331d
--- /dev/null
+++ b/tests/src/Mod/Part/App/TopoShapeExpansion.cpp
@@ -0,0 +1,3 @@
+//
+// Created by Chris Hennes on 1/11/24.
+//