If I create block A with the appropriate texture MAPPING parameters then duplicate, explode it to tweak it and create block B and then I apply the same MAPPING parameters as block A the textures don’t line up. They are off.
Only way for this to work or the textures to align is to explode both, apply same textures parameters, then make block a and then block b
Additionally when the block is closed (made) the textures appear one way and when I block edit the textures change.
Can you post your 3dm with the two blocks please? Also, are you assigning the texture mapping by object Properties prior to blocking or during a block edit? Or is the texture mapping being specified within the material’s texture settings? I’ve tried to mock up a scenario like you described but I think I’m missing some details.
My only guess so far is that the mapping is set within the material texture as WCS so the block positions in world coordinate space are the reason the mapping changes.
In short, the issue appears to be that primitive mappings (e.g. Planar, Box etc.) don’t stay with blocks if the block is moved outside of the block editor such as when importing the block to a new location in the scene. The only workaround I can see is to use by surface mapping or create a custom unwrap which will replace the surface UVs.
My workaround in the past was to work with meshes instead NURBS and apply a needed mapping, export the mesh object as obj and reimport. So, the mesh coordinates are “burned in” in the mesh and can’t be lost anymore.