Exception when deleting orphan IfcProductDefinitionShape in xBIM Essentials v6.0.517

[Surya7032]

After upgrading to xBIM Essentials v6.0.517, we are encountering an exception while attempting to delete an orphan IfcProductDefinitionShape from the model.

During IFC validation, a schema error is reported for IfcProductDefinitionShape.ShapeOfProduct. In this scenario, the corresponding IfcObject is not created, which results in an unreferenced (orphan) IfcProductDefinitionShape remaining in the model.

To clean up the model, we attempt to delete this orphan entity programmatically. However, calling Delete on the IfcProductDefinitionShape now throws the following exception:

**The method or operation is not implemented. **

This behavior differs from earlier versions of xBIM Essentials, where the same deletion logic worked without throwing an exception.

Steps to Reproduce:

1)Load an IFC file containing an invalid or missing ShapeOfProduct reference.

2)Validate the model and observe the schema error for IfcProductDefinitionShape.ShapeOfProduct.

3)Attempt to delete the unreferenced IfcProductDefinitionShape from the model.

4)An exception is thrown stating that the method or operation is not implemented.

Expected Behavior:

The orphan IfcProductDefinitionShape should be deletable, or an alternative supported mechanism should be available to safely remove such unreferenced entities from the model.

Actual Behavior:

Calling Delete results in a NotImplementedException.

Request
Could you please advise:

Whether deleting IfcProductDefinitionShape is intentionally unsupported in v6, or

If there is a recommended alternative approach for removing orphaned entities in xBIM Essentials v6?

Any guidance or documentation reference would be greatly appreciated.

[andyward]

Deletion has never been supported in the Esent Model. If you're using the default 'HeuristicModelProvider' it uses the EsentModel to load large models, rather than the MemoryModel (which supports deletion). Try forcing it to load in a memory model (there's a optional file size paramater on IfcStore.Load() I think)

[Surya7032]

We were previously using Xbim Essentials v5.1.259.0 with EsentDatabase (XbimStoreType), where the Delete operation worked correctly. After upgrading to Xbim Essentials v6.0.565.0, the same Delete operation now fails, and we are consistently encountering this issue.

[andyward]

Can you provide the stack trace (in text rather than as an image) - and ideally what you're doing in RemoveIfcProductDefShape (especially where you're interacting with IfcStore)?

I'm pretty certain you will have been using MemoryModel previously - despite the XbimStoreType flag. Esent has never supported deletion - Delete_Reversible has always been NotImplemented.

My guess is it's the DI system changes in v6.0 mean you're now using the Heuristic model provider which may not be ideal for your use case as it's write behaviour will change depending on the IFC file size.

[Surya7032]

        public void RemoveIfcProductDefShape(long productDefShapeInstId)
        {
            using (var txn = m_bimobjectCreator.GetModelObject().BeginTransaction("IsRepresentationUsed"))
            {
                try
                {
                    if (dictIdToProductDefinitionShape.ContainsKey(productDefShapeInstId))
                    {
                        var ifcObj = dictIdToProductDefinitionShape[productDefShapeInstId];

                        var shapeReps = ifcObj.Representations.ToList();

                        foreach (var shape in shapeReps)
                        {
                            m_bimobjectCreator.GetModelObject().Delete(shape);
                            var keyToRemove = dictIdToShapeRepresentation
                          .FirstOrDefault(kvp => kvp.Value == shape).Key;
                            if (keyToRemove != 0)
                                dictIdToShapeRepresentation.Remove(keyToRemove);
                        }

                        m_bimobjectCreator.GetModelObject().Delete(ifcObj);

                        dictIdToProductDefinitionShape.Remove(productDefShapeInstId);
                    }

                    txn.Commit();
                }
                catch (Exception ex)
                {
                    txn.RollBack();
                    ExceptionLog("Exception occurred while finding the Representation and the exception message is:{0}",
                              ex.Message);
#if DEBUG
                    MessageBox.Show("Exception occurred while finding the Representation and the exception message is:{0}",
                              ex.Message);
#endif
                }
            }
        }

While calling Delete function above exception is thrown..and we are creating the EssentDataBase as below

        public IfcStore GetModelObject()
        {
            if (m_model == null)
            {
                var credentials = new XbimEditorCredentials();
                XbimStoreType xbimStoreType = XbimStoreType.EsentDatabase;
#if NetStandard2_0
                xbimStoreType = XbimStoreType.InMemoryModel;
#endif
                m_model = IfcStore.Create(credentials, (m_ifcSchema == IfcSchema.Ifc2x3) ? XbimSchemaVersion.Ifc2X3 : XbimSchemaVersion.Ifc4x3, xbimStoreType);

            }
            return m_model;
        }

[andyward]

Is NetStandard2_0 actually defined in your project? If not, you're just creating an EsentDatabase internally in the IfcStore - not the InMemoryDatabase

                XbimStoreType xbimStoreType = XbimStoreType.EsentDatabase;
#if NetStandard2_0
                xbimStoreType = XbimStoreType.InMemoryModel;
#endif

In my vanilla NET8.0 test project it's not defined so this test fails:

Expected type to be Xbim.IO.Memory.MemoryModel, but found Xbim.IO.Esent.EsentModel.

[Surya7032]

We were previously using Xbim Essentials v5.1.259.0 . This also created Essent Database. With this delete had worked. But with the Xbim Essentials v6.0.565.0, it is not working. Could you please suggest any other alternative so that the orphan productdefinitionshape could be removed. As we export large models, we can't change it to MemoryModel.

[andyward]

We were previously using Xbim Essentials v5.1.259.0 . This also created Essent Database. With this delete had worked. But with the Xbim Essentials v6.0.565.0, it is not working. Could you please suggest any other alternative so that the orphan productdefinitionshape could be removed. As we export large models, we can't change it to MemoryModel.

I don't think this is a regression. It has never been possible to delete entities in the EsentModel, so you must have been using MemoryModel without realising. Implementing/Fixing EsentModel's Delete is tricky due to the need to 'collect' orphaned entities in Esent without creating integrity issues.

Is NetStandard2_0 actually defined in your project? If not, you're just creating an EsentDatabase internally in the IfcStore - not the InMemoryDatabase