Hello.
I found a bug in the STEP exporter.
If an object is on a layer with a custom Layer Color (any color other than black) and its Display Color = By Layer, then when exporting to STEP (.stp) Rhino for some reason assigns the object a new Display Color equal to the layer color.
After export, this color becomes an explicit object color instead of an inherited layer color.
Additionally, if the exported STEP file is imported into a new Rhino document, all imported layers appear black, and the objects receive an explicit Display Color taken from the original layer color. The layers should keep their original colors instead of turning black.
Expected behavior:
Rhino should preserve the Display Color and not assign the layer’s inherited color as a new object color during STEP export.
Tested in Rhino 8.
Thank you.