Color on imported STP file

I imported a part with SimLab STP but i can’t apply color on it. Is there a way to do it?

Could you upload the .skp file?
So we can have a look. (upload sign is 7th of left)

The file is too big… (1.8 MB)

Here you go! Thanks!

Your model contains about 1200 nested components which are all colored Gray (both backface and front face) If you want to color a component or group , the colors of the faces need to be the default color.
You can explode the component ( I think you need to do it 7 times) and end up with appr. 50.000 entities!
That’s a lot for a component this size. Most faces aren’t oriented as well (eg. backfaces pointing forward) so you would have to check that as well. Also: little gaps in geometry.
This thing happens a lot when importing Rhino or DWG. Sometimes it is faster/better to redraw in SketchUp…
Here’s a exploded (x7) and regrouped version: (1.3 MB)

Thanks !