In many cases Developers want to have a single file which contains their complete model and then they to append to that file a list of objects which should be removed from the scene after the HSF is read. This allows Developers to send out a small attachments which could modify already existing files. The HOOPS/Stream toolkit enables kind of functionality via the TKE_Delete_Object opcode. The general process is that you determine the tags of the objects you want to be removed from the scene and then you create a separate TKE_Delete_Object opcode for each of these objects. When the HOOPS/Stream toolkit is processing a buffer which contains a TKE_Delete_Object opcode it will determine the key of the tagged entity from it's internal hash table and then delete that object from the graphics systems displaying the HSF.
For Developers who are using the base classes for reading HSFs they will need to implement their version of TK_Delete_Object::Execute(...) to ensure that the object is deleted from their graphics subsystem.