It’s just a rotated minimum bounding box component made by @RIL ( Minimum oriented bounding box. Implementation in Grasshopper + Python script node - #61 by RIL ). Each cube is referencing an oriented minimum bounding box so the box mapping is almost identical to the geometry that is being textured. In this case I would expect to receive perfect grid since Geometry (cube) = Box Mapping Widget.
But to make things even simpler we can remove the minimum bounding box component completely and directly cast Model Objects to Box and use it in the Box Texture Mapping component. As you can see, one of the boxes have two faces showing stretched lines instead of grid.
In my previous post I didn’t graft one input, but it didn’t make a difference. Here are updated files:
GH Texture Mapping TEST 3.gh (11.1 KB)
GH Texture Mapping Test 3.3dm (230.9 KB)
Clue of the video is that after the Grasshopper solution, two sides of one Model Object are stretched (and they shouldn’t be), the slightless change in the Rhino UI fixes this problem. So it looks like something is off when pushing the texture mapping through Grasshopper.