how to use newfamilyinstance method to create a mass familyinstance

[comic3344]

I want to use newfamilyinstance method to create a mass familyinstance.

This method have 12 overloads, and I want to pickup a face for this mass familyinstance.

The problem is that the mass familyinstance is not a WorkPlaneBased type.

But, if I add a mass familyinstance into a project without API, I should pickup a face for it.

Please help me. Thank you!

[comic3344]

I am sorry about my description.

The rft file is not mass.rft. The Conceptual Mass have the function about the face based.

Actually, I use the Generic Model Adaptive.rft file to make a new family.

And then, I create this new familyinstance by API .

The Generic Model Adaptive.rft is not face base, so the newfamilyinstance method is fail.

Please help me. Thank you!