Import Multiple Step Files into Single Design

[nick.sherwood]

I'm trying to do something simple with my Fusion 360: insert several step files from Thor Labs (optomechanical supplier). I can easily open any of their step files by themselves. However when I try to insert a new component into a single design (using the Insert Mesh command) it appears to open the new step file, visually shows it in the window, and opens the Insert Mesh window. However the "OK" button is greyed out and there's nothing I can do to finish my insert. I've seen other posts which I think are related, but nothing that solves my problem. Any thought? Thanks

[jeff_strater]

most likely, those STEP files are not mesh files, they are likely surface or solid geometry.  Insert Mesh only works with mesh files (OBJ, STL, etc).

The best way to do this is open or upload both STEP files, which will create Fusion designs in your project.  Then, either Insert from the data panel, one design into the other, or both into one top-level design.  If you need to modify the designs, you can Break Link to convert the external reference into local components.