The reference plane created using the familyDoc.FamilyCreate.NewReferencePlane() method is in the model interface, while what I need is in the sketch interface
【Revit 2025】Is there any way to use the API to create a reference plane in the sketch mode of a NewExtrusion family?
I don't think it is possible to integrate any API functions while Revit is not in Idle state mode [ a state where no user inputs are expected to complete a pending running command], in your case the pending command is Extrusion finish [or as you named it, Sketch interface].
Moustafa Khalil
