I made a script that project points to a mesh and extrudes lines, and this shows that OpenGL thinks that the quad meshes are different from what Rhino thinks:
If I triangulate the mesh then the points are correctly placed on that triangulated mesh:
Thanks for catching this @Holo. Reported: https://mcneel.myjetbrains.com/youtrack/issue/RH-43763.
Hi David,
I see that this hasn’t been solved yet.
I did some testing and OpenGL seems to ignore the Rhino default of dividing on the shortest diagonal. Do you know why?
It is frustrating that OpenGL isn’t identical to the mesh that Rhino uses for calculations. We need WYSIWYG 
Thanks!
Here you can see an example where they differ:
This is just a small mesh made with Heightfield from image tool, and then used Contour so it is easy for you to reproduce the example.
Looks like @jeff hasn’t gotten to this yet Patience. Now he’s been tagged at least.
YT item: https://mcneel.myjetbrains.com/youtrack/issue/RH-43763.
What does this strange word mean? 
(By the way @DavidEranen , you did notice that the initial post was from January 2018 and not January 2019, right? )
I did But as you know, YouTrack has quite a lot of items assigned to v7, so it’s all about prioritizing. We won’t forget about it as long as it’s recorded on YouTrack.
Ok, good
And I hoped that representing meshes correctly was a v6 bug fix priority.
Cheers
