Creo 8 & 9: C++ Object Toolkit does return nullptr for pfcSolid::GetIsSkeleton()

Hello PTC, Hello PTC Community,

Currently in Creo 4 and Creo 7 we check whether a part is a Skeleton model to handle different assemble behaviors for Skeleton and non Skeleton parts.

However, in Creo 8 & 9 this stopped working. Whatever I try, I get a nullptr from calling 

pfcSolid->GetIsSkeleton()

The open toolkit user guide (otkug) does still include this method...

❓

• Is this a bug? 
• Is someone using the GetIsSkeleton function on Creo 8 or Creo 9?