@mikrocoder I looked at the posted STEP files… OMG!
These are about the worst Model’s I’ve seen in years - not so much in the ‘design’ approach (though, a better approach would have yielded a much better, efficient result) but, rather in the composite of the designed ‘features’ (Body’s and Part’s, in FreeCAD terms).
Example: Handful of items were Difference’d then, Unionized, though redundant, that’s fine, but, they were left in place afterwards and ‘that’ causes their Colors to Bleed with the same base-items (that is what @paulvdh is hinting at - color bleeding from items at the same position in space).
I started cleaning up the ‘with’ file but ran out of coffee so, I stopped. Below screenshot of some deletion’s (and item ‘hiding’). After cleaning a dozen items, I ‘Compounded’ them to yield a unified ‘item’ that does not Bleed… did not finish any of it, though. FreeCAD File attached for your inspection. If it were me and I needed to use one of these files, I’d go through the items in the Tree and ‘Hide/Show’ to see what’s going on then, select the necessary one’s and Compound them. When done, I’d select ONLY the ones comprising the resulted Compounds, Groups…etc and Export them. Don’t export all the items, that will cause Bleeding…
If you go through your STEP files, you can tweak to get a desired result and, ‘Learn’ something that will help you deal with similar STEP files.
Here’s my partially cleaned file…
woof.FCStd (564.1 KB)
Cubes get Difference’d then Unionized Thus, you would want to Hide all but the Unionized (hide or delete them… you decide…)
My ‘Unfinished’ cleaning shows No Bleeding and would yield a good STEP for use in Kicad.
