This is a tutorial using Octane for Cinema 4D. It demonstrates the creation of procedural materials (Rust, Worn Paint, and Water Stains) using a custom dirt map.
** This video is from 2014. Octane has changed a lot from the version in this tutorial (2.01.00). However, many of the concepts still apply. **
0:18 Using Noise with the DirtMap
1:30 Regular Dirtmap
2:58 Dirtmap with Noise
13:58 Worn Paint
17:18 Mildew/Water Stains