Graphics Reference
In-Depth Information
Node-Based Material Textures
Youcan doalot with Cycles material nodes.Inthis section, I'll walk throughthe steps ofusingCycles material
nodes to set up a simple grunge map for a metallic material. Grunge mapping, like the related technique of dirt
mapping, means adding patterns of corrosion, rust, dirt, or wear to textures in a way that suits the shape of the
textured object. This can be done by hand or by using a variety of techniques to get appropriate patterns. Ambi-
entocclusion isacommonintermediary toolforcreating grungemaps,because itcalculates values onanobject
based on the object's recessed and protruding geometry, which often roughly matches where you would expect
to find grungy buildups and buffed clean areas on an object.
You can follow along by using the texture images you will find on the website for this topic. The copper
texturesareshownin
Figure4-25
.
Thefirstoneisarelativelyclean,reddishcopper;thesecondismostlybluish
corrosion. The copper textures were created by modifying textures from
http://www.cgtextures.com
, and they
are made available with permission from the copyright owner. Other textures from that website are available
free of charge for use in commercial and noncommercial projects, with the stipulation that the textures them-
selves not be redistributed.
Figure 4-24
The object lit by the image
