References:
Time-saver: Smart UV Project
does wonders for some meshes, mostly when there are no rounded parts on it.
It is useful to check that the UV unwrapping does not result in too much stretching of the texture using a checkerboard texture.
To activate:
- Click on the circle button on the right-hand side of principled shader's
Base color
field. - Select
Checker texture
. - adjust scale as suitable.
Alternative:
- In the image editor, create new image, selecting
UV Grid
Generated type option. - Edit the material to use the new image instead of
Base color
.
In the UV image editor's side View
menu, activate Stretch
overlay in order to see a heat map of the stretching.
Reference: Anvil tutorial.
In case different portions of the mesh need to be applied a different material, create two materials, and click on "assign" with the relevant portion of the mesh selected in edit mode
.
More often, it is desirable to have a managed transition between both materials, or to get a mix between both (think: rust over metal).
In this case, a mix shader should combine both materials, using either noise + colorRamp or texture paint should be used as a masking factor.
Reference: Anvil tutorial - Texturing part 2.
Feature overview by CG Cookie.