Hi Martin, pretty much the only similarity between STL file and OBJ files are that they are both polygon file formats.

STL files are very bare bones and were only designed for sending data to a 3D printer, not as a way to store models for working on.

STL files are intended to contain only one solid in them, they don't have any material information, can only contain triangles, and don't even have a structure with an indexed shared vertex list. They are just a big list of triangles without any connectivity information.

They should not be used as your main file format for any kind of work in progress, you should only generate them as needed for 3D printing processing.


> I suppose the way around this would be to find a file translator to go from
> STL to OBJ and bring it in that way.

It isn't really just a problem of translation between file formats - STL files contain only triangle mesh data and MoI is not designed to work on triangle mesh data. Just translating the same not-applicable-to-MoI data between different formats will not really be a solution.

If you need to work on an object that is defined using triangle mesh data, you would want to use a polygon mesh editing program that is designed to work with that kind of data which MoI is not.

- Michael