Hi Marek, the type of mesh geometry you show there isn't suitable for sub-d smoothing. A mesh designed for sub-d smoothing should be made up primarily of quads and structured as described at https://www.youtube.com/watch?v=ckOTl2GcS-E .

What you have there is non-subd triangle mesh geometry, so it's not going to work right for using it as a sub-d control cage.

MoI is not designed to work with triangle mesh geometry like that.

If you can export from ArchiCad to .stl format you might try using an STL viewer type program such as https://www.materialise.com/en/software/minimagics , those are likely to have a weight calculator function.

- Michael