The alCurvature shader measures the local curvature of the surface. This shader is an easy way to add detail and realism to your shaders. In this short tutorial we will use the alCurvature shader to mimic a shading painting technique effect on a model of a lead figurine.

Layer alSurface Shaders

An alLayer shader is used to layer two different alSurface shaders. We will use one alSurface shader for the black paint layer and another alSurface shader to represent the exposed metallic surface underneath.

• Create an alLayer shader and assign it to the object.
• Create an alSurface shader and rename it Black Paint. Connect it to Layer 1 of the Layer shader.
• Create another alSurface shader and rename it Metal. Connect it to Layer 2 of the Layer shader.

alCurvature Shader

• Connect the alCurvature (Outcolor R) to the Mix attribute of the alLayer shader. This will control the blending between the two alSurface shaders.

• You can use the Radius attribute to pick out finer details in the figurine model. The default value of 1 is too large for our model. Reduce it to around 0.01. The images below show the effect this has on the alCurvature shading.

Final shader network