In the previous installment on using the Corrosion shader, we talked about what the parameters mean. Nos we will explore the mapping and layering of Corrosion shaders.
Mapping
The way in which the shader is mapped can yield a variety of effects.
Scaling
The way in which a corrosion shader is scaled can yield a variety of different appearances The image below shows a gold texture with a corrosion shader and the texture coverage set to (left to right) 100%, 10% and 1% both in x and y.
Different coverage for a texture shader (UV mapping)
Controlling the coverage using different values for the different axes we can achieve different looks too.
With large x-coverage and small y-coverage we can achieve a “lathed” look.
With large y-coverage and small x-coverage we achieve a striated look.
We can obtain different kinds of pitting combining differnet x-and-y coverages.
Below a 1% coverage, the shader tends not to show much difference. The spheres on the left have a 1% horizontal coverage. The one on the right has a 0.1% and the lines are lost.
Layering
Another way to control how the Corrosion shader works is layering the shader to create different effects.
As was mentioned in the first part, using the Inherit Mix mode, we can make holes in the corrosion shader show through the underlying texture and show either holes in the object or an underlying texture.
The sphere on the left has vertical striations, the one on the right has horizontal ones. The one in front combines both. The sphere in front has two gold textures applied, each one with an associated corrosion shader (the same one, only mapping changes). The “secret”, once more is to set the Mix to Inherit.
In the example below, the rust texture is set to Replace, and the gold texture, to Inherit, and so, the holes in the gold show the underlying rust.
The rust texture is set to Replace, the gold texture, to Inherit
The same logic applies to paint, metal, and rust. Paint and metal are set to Inherit Mix.
An interesting application is pewter. Pewter is “a malleable metal alloy, traditionally 85–99% tin, with the remainder consisting of copper, antimony, bismuth and lead.”, says Wikipedia. Pewter has a pitted surface which we can simulate using a corrosion shader and dark and light metal textures.
The result can be seen below.
You can download the zipped scene file here.
These are some ways in which we can use the Corrosion shader. I look forward to seeing more ways in which you use the shader too.
