Hi BR, yes it's probably related to your large file sizes. But just to make sure it's not some other problem I'd recommend testing with a small file like just a single box, not something in the 10mb+ range like you've been doing.

CAD models are not really meant to be made up of many hundreds of thousands of little flat faces like you will have in a polygon file format. It's meant to have large smooth surfaces that have trimming information on them. It does not work very well to have a hundred thousand little flat surfaces with trimming information on each one because there is some additional overhead for that entire concept of an "underlying surface" that has trimming curves on it.

So generally I would not recommend trying to load such heavy polygon objects into MoI, you would be better off using a polygon modeling program to do that, not MoI.

Sometime in the future I could see adding in a concept of a separate polygon mesh object type in MoI which would then better fit OBJ format data, but having different categories of objects which don't really interact with each other and need their own separate tools leads to a lot of confusion about why some particular object behaves differently than others and tends to require a lot more UI with specialized tools. That's why I have not focused on doing that so far. Keeping MoI focused just on NURBS modeling at runtime is one of the things that helps make it simple and easier to use.

- Michael