I encounter many problems with user defined texture mappings in Rhino 7. I’ve reported some of them here for Rhino 5 and was told it has been fixed with Rhino 6. I have not tried Rhino 6 but recently upgraded to Rhino 7 just to find out that it has become even worse. This is very depressing.
In this example, within the same host file, the linked block definitions behave different. On the left side, the yellow highlighted block file shows messy textures while looking correct in the block instance, on the right side the red highlighted block file looks correct but messy in the instance.
In Rhino 5 only the first bug existed, so I put thousands of objects with user defined texture mappings into block instances to make them appear correct as workaround. Now in Rhino 7, this workaround randomly fails for whatever reasons; in some host files, same block instance looks correct while in another host file it is messed up for no obvious reason.
Another weird behavior is, that when you cut and repast objects with messy textures, they show up correct:
However, as soon as you save the file and reopen it, the mess appears again, so it definitely is not a viewport problem. Also, when you export the objects into SimLab Composer, the mess persists. Very frustrating.