Doc:Tutorials/Materials/BSoD/part1i

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[edit] Adding a History to a Material (Getting Dirty)

Close examination of the real desk surface show polish and dust accumulation, as well as a few knocks and marks, here and there. If we can add these subtle hints to the materials history we can produce a much more pleasing material simulation.

A materials history can be broken down into 3 possible areas

[edit] Dirt

All real materials get dirty either by dust in the atmosphere or by interaction with liquids or sticky substances.

dust will collect in crevices
dirt will transfer from mucky hands or dirty objects onto a surface over time.

[edit] Damage

Given time any surface will sustain damage either by interaction with atmosphere or by being knocked or marked directly.

[edit] Other things applied to a surface such as posters or labels

In this modern age we can’t leave a natural surface alone. Labels either stuck on, or embossed in, a surface are commonplace.

Even natural surfaces interact with growing things that will attach themselves to a surface and therefore alter its material properties.

Although the real desk surface is pretty clean there is nothing to stop us adding a little dirt & damage. I sometimes enjoy a cup of coffee at my desk. While I typically use a coaster to protect the desk surface lets pretend that I have in the past placed an overfilled coffee cup on the desk surface.

NOTE:

On close examination of my desk I, and my cleaners, can categorically state that it is one of the cleanest desks in the land. HONEST.

The stain of a coffee cup is a unique shape and we therefore can’t use a procedural texture to imitate it. However, such a stain is very easy to produce and get into Blender.

The image above was created by placing a coffee cup on paper, drying off and then scanning to an image. Finally I cleaned up the picture in a paint program to give more contrast.

NOTE:

As I have said before it’s always a good idea to pause occasionally when working on this addictive 3D material creation. A cup of tea, coffee, chocolate or other libation will force you to relax and exercise you legs.