Change lighting for formats that don't include it?

[gene-ressler]

Beautiful tool. Thanks.

For OBJ files and similar having no lighting info, it would be great to have controls to manually give a simple source's direction, just so it's possible to see variations in vertical surfaces. It looks like I'm getting a parallel source - which is fine - pointing toward minus-z. Consequently, anything that's near vertical is all the same flat color. If there is a way to change this, I can't find it.

Another option would be to have a fixed source that is unaffected when the model is tumbled in the UI.