Hi ,
Thanks for bringing this up. We have received reports of this and confirmed that there is an issue with certain meshes imported from SketchUp through Datasmith causing them to appear glossy and dark, and completely black in Path Tracer. The development team is looking into this and working on a fix.
For now, since the issue is specific to Datasmith, we recommend importing the affected models as SKP files into Twinmotion, which doesn't get affected by this issue. You only need to import the affected models/meshes as SKP files, and the rest of the models that are unaffected can be imported through Datasmith until we have a fix for this.
Best,
Raghib