This problem has been addressed many times before for copying UV's from one object to another object. But I need to copy UV map scale from one face group to another within the same object. In the example I've a brick texture that I've sized 15 times on X and Y. Now when I apply the same material to the chimney the texture is much smaller because the UV map is smaller. I can scale it by hand in the UV editor, but it will be difficult to hit the same scale factor and it just seems so random to do. Is it possible to just copy the UV scale from the walls? I know it's possible in 3DS Max..
How we usually go about matching the uv is to scale all the uv which are suppose to have the same materials together after matching the scale with Ctrl+A (Match island scale operation.) If this is impossible in a particular workflow. Then try the following:
We usually end up using a checker map pattern to eyeball the sizes of the checker, to approximate the scale of every surface before applying the actual material.
- Create a color checker image go for 2048x2048
- Apply the checker to all the surface of the model.
- Enter Edit Mode and duplicate the faces in question and move it near the faces that has the scale you want to match. (Step for easier eyeball comparison)
- Select the duplicated face in the UV Editor and start scaling.
- Match the sizes in the checker pattern, and take note of the scaling factor on the bottom left hand of the uv scale before hitting LMB .
- Delete the duplicated face.
- Enter the scale value from step 5. to the faces you want to affect.
If these answers are not satisfactory or understood, will be glad to post some images to help explain the workflow.