I need to export an assembly to optical design software Zemax. The assembly consist of two of the same part that I mated together.

When I export it to Zemax (STEP file), it comes as one object, which is correct. Then I define the material for this object.

But once I launch the ray, this object acts like two object mated together, (the ray did not go through the boundary where I mated the two parts in Solidworks, even with the same material).

Anybody know how to export Solidworks assembly file into one object in Zemax? One object here means that the mated face between two parts in Solidwork is ignored by the ray.

Thanks.