I am trying to apply a roof tile texture to the roofs of different houses with differently sized roofs. I am unwrapping the roofs so as to be able to rotate each element separately so that the roof tiles are always aligned in the right way.
How can I use some common base of reference to ensure the texture size is the same on all roofs?
My current attempt is this:
unwrap one roof
open the UV Editor, setting a fixed size for the UV-space (e.g. 1000x1000)
rotate the islands in the UV Editor and scale them so the texture is mapped as I want it
copy the mesh outlines to act as reference for other roofs
apply and close UV Editor
unwrap the next roof
open the UV Editor, setting the UV-space the same size as before (1000x1000)
rotate and scale the islands of the second roof in reference to the mesh outlines from the first roof
apply and save
Result: The texture scaling is completely different between roof 1 and roof 2.
The problem is that the scale of the texture shown/applied inside the UV-Editor is not persistent. Every time I open the UV-Editor it automatically adjusts the texture scale and tries to fit all islands inside the UV space, even if I have scaled them to extend that 1000x1000 space before.
How can I ensure the texture scaling and UV-space scaling do not change every time I re-open the UV-Editor?
Or should I go about setting an equally sized texture mapping on a number of unwrapped objects in a completely different way?
Should I not use ‘unwrap’ at all?