Graphics Reference
In-Depth Information
The problem we face at this point is that the chips are spread randomly throughout the surface of the curb.
In the real world, this kind of wear appears more frequently on the edges of materials, where more abrasive
contact is usually found. To constrain the chips to the corners, you will use an Ambient Occlusion material
as the layer mask on the Group Mask:
1.
Add the texture to the material, which is found in the Processing section when adding Shader Tree
layers.
2.
At first, this will be added to the Diffuse Color layer. Using this default setting to modify the texture
layer will give better control and quicker feedback. You will immediately see that the Ambient Occlu-
sion texture does not appear in the real-time viewports and that the only way to see it is in the preview
render window (or by doing a full render). If this gets a bit too slow while editing, you can turn off the
Irradiance Cache updates while texturing. This is done with the IC: Update button at the upper-left side
of the preview window. Turning this off will decrease redraw time and help you adapt the texture more
quickly.
3.
When first applied, Ambient Occlusion has the Type set to Uniform. This produces a result that is
too soft for our use. Changing the Type to Concavity & Convexity will put the textures at the edges
and creases. The texture will show a lot of noise because the material has a displacement map.
4.
To fix this noise, change the displacement map to Bump (and set the blend mode to Add). Because
this will be acting as an alpha, the Occlusion should be inverted to show white on the edges and in the
creases, as shown in
Figure 12-16
.
Figure 12-16:
The Occlusion texture can essentially mask off sections of geometry based on the shape
of the mesh.
