Quick Tip: How to Make Easy Grunge in Blender
You know when you move some furniture around there's always a noticeably clean patch of carpet where the furniture used to be? That's because dirt is everywhere, and it takes some serious elbow-grease to get anything as perfectly clean as most CG renders look. It's easy to add a lot of dirt everywhere, but that's not how the real world works. We need to add dirt in specific places and make it look like it just naturally formed there. The texture map that does this is called a dirtmap.
There are many different types of dirt, too many to cover in one short post, so in this tutorial you'll learn how to add the most common kind: Grunge.
Grunge is like any other dirt – a collection of various little particles – but it's bound together with oil and grease making it especially stubborn and disgusting. It collects in the cracks and corners which protect it from being easily cleaned off by both us and the weather.