Hello,
I have tried mesh simplifictaion with several cars (FBX and OBJ) and I always get a bad model.
This especialy at the seems of the doors. I don’t know if this is a bug or it just can’t be more simplified (over 50%)?
Thanks!
These kinds of artefacts can appear, depending on how the model topology was constructed.
The less faces in the model, the less details can be represented, so you should expect this when you reduce the geometry too much.
In this case I’d suggest to simplify less.
Another thing to try: once in SketchUp, unsmooth all edges, then play with the “Soften edges” dialog to see if you get a better result.