diff --git a/code/Importer/IFC/IFCGeometry.cpp b/code/Importer/IFC/IFCGeometry.cpp
index ba9098b6f..d49e5cb01 100644
--- a/code/Importer/IFC/IFCGeometry.cpp
+++ b/code/Importer/IFC/IFCGeometry.cpp
@@ -728,7 +728,7 @@ void ProcessSweptAreaSolid(const Schema_2x3::IfcSweptAreaSolid& swept, TempMesh&
 }
 
 // ------------------------------------------------------------------------------------------------
-bool ProcessGeometricItem(const Schema_2x3::IfcRepresentationItem& geo, unsigned int matid, std::vector<unsigned int>& mesh_indices,
+bool ProcessGeometricItem(const Schema_2x3::IfcRepresentationItem& geo, unsigned int matid, std::set<unsigned int>& mesh_indices,
     ConversionData& conv)
 {
     bool fix_orientation = false;
@@ -810,7 +810,7 @@ bool ProcessGeometricItem(const Schema_2x3::IfcRepresentationItem& geo, unsigned
     aiMesh* const mesh = meshtmp->ToMesh();
     if(mesh) {
         mesh->mMaterialIndex = matid;
-        mesh_indices.push_back(static_cast<unsigned int>(conv.meshes.size()));
+        mesh_indices.insert(static_cast<unsigned int>(conv.meshes.size()));
         conv.meshes.push_back(mesh);
         return true;
     }
@@ -818,33 +818,31 @@ bool ProcessGeometricItem(const Schema_2x3::IfcRepresentationItem& geo, unsigned
 }
 
 // ------------------------------------------------------------------------------------------------
-void AssignAddedMeshes(std::vector<unsigned int>& mesh_indices,aiNode* nd,
+void AssignAddedMeshes(std::set<unsigned int>& mesh_indices,aiNode* nd,
     ConversionData& /*conv*/)
 {
     if (!mesh_indices.empty()) {
+		std::set<unsigned int>::const_iterator it = mesh_indices.cbegin();
+		std::set<unsigned int>::const_iterator end = mesh_indices.cend();
 
-        // make unique
-        std::sort(mesh_indices.begin(),mesh_indices.end());
-        std::vector<unsigned int>::iterator it_end = std::unique(mesh_indices.begin(),mesh_indices.end());
-
-        nd->mNumMeshes = static_cast<unsigned int>(std::distance(mesh_indices.begin(),it_end));
+        nd->mNumMeshes = static_cast<unsigned int>(mesh_indices.size());
 
         nd->mMeshes = new unsigned int[nd->mNumMeshes];
-        for(unsigned int i = 0; i < nd->mNumMeshes; ++i) {
-            nd->mMeshes[i] = mesh_indices[i];
+        for(unsigned int i = 0; it != end && i < nd->mNumMeshes; ++i, ++it) {
+            nd->mMeshes[i] = *it;
         }
     }
 }
 
 // ------------------------------------------------------------------------------------------------
 bool TryQueryMeshCache(const Schema_2x3::IfcRepresentationItem& item,
-    std::vector<unsigned int>& mesh_indices, unsigned int mat_index,
+    std::set<unsigned int>& mesh_indices, unsigned int mat_index,
     ConversionData& conv)
 {
     ConversionData::MeshCacheIndex idx(&item, mat_index);
     ConversionData::MeshCache::const_iterator it = conv.cached_meshes.find(idx);
     if (it != conv.cached_meshes.end()) {
-        std::copy((*it).second.begin(),(*it).second.end(),std::back_inserter(mesh_indices));
+        std::copy((*it).second.begin(),(*it).second.end(),std::inserter(mesh_indices, mesh_indices.end()));
         return true;
     }
     return false;
@@ -852,7 +850,7 @@ bool TryQueryMeshCache(const Schema_2x3::IfcRepresentationItem& item,
 
 // ------------------------------------------------------------------------------------------------
 void PopulateMeshCache(const Schema_2x3::IfcRepresentationItem& item,
-    const std::vector<unsigned int>& mesh_indices, unsigned int mat_index,
+    const std::set<unsigned int>& mesh_indices, unsigned int mat_index,
     ConversionData& conv)
 {
     ConversionData::MeshCacheIndex idx(&item, mat_index);
@@ -861,7 +859,7 @@ void PopulateMeshCache(const Schema_2x3::IfcRepresentationItem& item,
 
 // ------------------------------------------------------------------------------------------------
 bool ProcessRepresentationItem(const Schema_2x3::IfcRepresentationItem& item, unsigned int matid,
-    std::vector<unsigned int>& mesh_indices,
+    std::set<unsigned int>& mesh_indices,
     ConversionData& conv)
 {
     // determine material
diff --git a/code/Importer/IFC/IFCLoader.cpp b/code/Importer/IFC/IFCLoader.cpp
index 9faf68cbb..a40eedc1d 100644
--- a/code/Importer/IFC/IFCLoader.cpp
+++ b/code/Importer/IFC/IFCLoader.cpp
@@ -435,7 +435,7 @@ bool ProcessMappedItem(const Schema_2x3::IfcMappedItem& mapped, aiNode* nd_src,
 
     msrc = m*msrc;
 
-    std::vector<unsigned int> meshes;
+    std::set<unsigned int> meshes;
     const size_t old_openings = conv.collect_openings ? conv.collect_openings->size() : 0;
     if (conv.apply_openings) {
         IfcMatrix4 minv = msrc;
@@ -550,7 +550,7 @@ void ProcessProductRepresentation(const Schema_2x3::IfcProduct& el, aiNode* nd,
 
     // extract Color from metadata, if present
     unsigned int matid = ProcessMaterials( el.GetID(), std::numeric_limits<uint32_t>::max(), conv, false);
-    std::vector<unsigned int> meshes;
+    std::set<unsigned int> meshes;
 
     // we want only one representation type, so bring them in a suitable order (i.e try those
     // that look as if we could read them quickly at first). This way of reading
diff --git a/code/Importer/IFC/IFCUtil.h b/code/Importer/IFC/IFCUtil.h
index 479772d89..194206d4b 100644
--- a/code/Importer/IFC/IFCUtil.h
+++ b/code/Importer/IFC/IFCUtil.h
@@ -205,7 +205,7 @@ struct ConversionData
         bool operator == (const MeshCacheIndex& o) const { return item == o.item && matindex == o.matindex; }
         bool operator < (const MeshCacheIndex& o) const { return item < o.item || (item == o.item && matindex < o.matindex); }
     };
-    typedef std::map<MeshCacheIndex, std::vector<unsigned int> > MeshCache;
+    typedef std::map<MeshCacheIndex, std::set<unsigned int> > MeshCache;
     MeshCache cached_meshes;
 
     typedef std::map<const IFC::Schema_2x3::IfcSurfaceStyle*, unsigned int> MaterialCache;
@@ -281,8 +281,8 @@ unsigned int ProcessMaterials(uint64_t id, unsigned int prevMatId, ConversionDat
 
 // IFCGeometry.cpp
 IfcMatrix3 DerivePlaneCoordinateSpace(const TempMesh& curmesh, bool& ok, IfcVector3& norOut);
-bool ProcessRepresentationItem(const Schema_2x3::IfcRepresentationItem& item, unsigned int matid, std::vector<unsigned int>& mesh_indices, ConversionData& conv);
-void AssignAddedMeshes(std::vector<unsigned int>& mesh_indices,aiNode* nd,ConversionData& /*conv*/);
+bool ProcessRepresentationItem(const Schema_2x3::IfcRepresentationItem& item, unsigned int matid, std::set<unsigned int>& mesh_indices, ConversionData& conv);
+void AssignAddedMeshes(std::set<unsigned int>& mesh_indices,aiNode* nd,ConversionData& /*conv*/);
 
 void ProcessSweptAreaSolid(const Schema_2x3::IfcSweptAreaSolid& swept, TempMesh& meshout,
                            ConversionData& conv);