Transcribing model entities¶
The main purpose of the session is to provide the SMTK model Manager which owns it with information about the entities in some foreign modeler and the Session::transcribeInternal() method is where your session must do this.
The first thing you should do is verify that the entity being requested actually exists:
One trick you’ll see in most sessions is the construction of a “mutable” entityref
from the const version that passed to
The const version does not provide access to methods that alter the model manager’s storage. Constructing a mutable version of the entityref is legitimate inside the session — we are pretending that the entity to be transcribed has existed in the manager ever since it existed in the foreign modeler. Since transcription should not change the entity in the foreign modeler, creating a mutable entityref is acceptable.
Once you know that the UUID has a matching entity in the foreign modeler, you should create an Entity instance in the model manager’s map from UUIDs to entities. Make sure that the entity’s flags properly define the type of the entity at this point but don’t worry about filling in the list of relations to other entities unless the SESSION_ENTITY_RELATIONS bit is set in the request for transcription.
If SESSION_ENTITY_RELATIONS is set, then you not only need to ensure that the relations are listed but that they are also at least partially transcribed. You are always welcome to transcribe more than is requested, but be aware that this can slow things down for large models. Because this is an example and because the Exodus session does not expose individual cells as first-class entities, we transcribe the entire model recursively.
Now you should check other bits in SessionInformation that are present in your Session::allSupportedInformation() method and ensure that information is transcribed properly before returning the bits which were actually transcribed for the given entity.
The Session::transcribe() method uses the return value to update its list of dangling (partially transcribed) entities.