I have a fairly complex object which has multiple materials in different faces. I would like to cover the whole thing in dirt (for example noise texture).

I know I can use multiple UV's (this technique http://www.andreucabre.com/2012/02/multiple-uvs-and-decals-in-cycles.html) but that would require to re-create the existing thing in a different manner (using UV's and nodes instead of multiple materials)

Is there a way to cover the whole thing with a semi-transparent texture?

I'm using cycles.

  • 3
    $\begingroup$ Blender internal or Cycles? $\endgroup$ Commented Sep 7, 2014 at 15:49
  • $\begingroup$ No, not counting hacks like duplicating the object and making the duplicate transparent except for the dirt texture.. I would use a nodegroup to apply the dirt texture to all the materials, however the setup for this depends on your existing setup.. Is it possible you could upload your .blend or some screenshots? $\endgroup$
    – gandalf3
    Commented Sep 8, 2014 at 7:57
  • $\begingroup$ I edited the question to include that I'm using cycles. I already went the way to create it again with one material and uv's, but the question still remains (my case was simple, I only had two materials) but let's say you have a character, with 50+ materials... $\endgroup$
    – qwazix
    Commented Sep 8, 2014 at 11:33
  • $\begingroup$ Applying the same noise (dirt) to all materials might work, yes, without the seams showing, if you use the same UV map for the dirt in all materials. I'm not going to upload a file, I'm just playing and trying to learn. The question is meant more as a discussion on how to solve the general issue, not my specific one, so branched answers are welcome (if you have this, then that) $\endgroup$
    – qwazix
    Commented Sep 8, 2014 at 11:39

1 Answer 1


One way would be to add a node group right at the end of all your materials:

dirt group

This way you would only need to setup/change the dirt shader stuff once, and it'll be used by all your materials the same way.

The nodes inside the group might be something like this (though it really depends on what you're doing):

dirt group inner

More info about node groups:


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