AddIn check which face is in contact with worksurface

[Jef_E]

Hi there!

I created an AddIn that splits a worksurface it's contour into a face. 

oDef.Features.SplitFeatures.SplitFaces(oItem, True)

The option True = split all, I wonder if I put false and add the face to split gives me extra speed?

My question for doing this operation is: How can I check for oItem what face(s) it is in contact with? For my needs this wil be 99% 1 face and sometimes 2 faces.