Here is something I’ve never seen before. I have a mesh object (it comes straight from Chaos Cosmos) and place it in the scene. Now I reference it in Grasshopper.
If I move around the object everything is fine until I move it above a certain value in Z and then it becomes and “Invalid Mesh”!? How can it become invalid just from moving around??
cosmos_books.3dm (132.4 KB)
This is in Rhino 7.3.21053.23031
wohaaaa!!! this is so weird
looks like the bottom mesh is the one causing the problem 
tried top move just that faulty one in steps of 0.1 units, it’s even wierder:
[edit] I think the problem is in duplicated vertex points, nothing to blame on Rhino 
I expect that mesh to have 12 faces, but it has 20
Rhino is not to blame for the way this is built, for sure. That would go to whoever at Chaos Group built this. But it’s definitely Rhino handling it in a weird way. It should either be invalid from the start or not at all, but moving it should have no influence on it.
What I find weird is that it only happens after a certain distance in Z. Could it be that the Z values of the Vertexes are like one significant digit apart and as soon as you move it above a certain value of Z, the accuracy basically makes it so that they then get rounded to the same value? Something like that?
Super weird. Can someone from McNeel take a look at this!?
I posted this also on the Chaos Forum and they already fixed the asset 
