This article explains the settings and values for the Corona Curvature shader in Cinema 4D.
Overview
The Corona Curvature Map is a new map added in Corona 8 that colors a mesh based on its convexity/concavity. It's useful in creating masks of the inward and outward curvy areas of a surface.
Shader Properties
Color spread – This parameter changes how rapidly the convex/concave colors replace the flat color as curvature increases. Increasing this value means the result has more of the convex/concave colors mixed in.
Max samples – This parameter defines how many samples are used. A higher value renders slower but produces clean results faster. Even low values eventually converge to a clean image.
Ray directionality – This parameter defines how strong the tested rays are concentrated around the normal. With a low value, all directions are considered equally. Increasing the value causes the shader to be more dependent on whether the direction directly above the surface is occluded or not.
Max distance – This parameter determines the radius that the curvature traces. This can be used to match the curvature between big and small objects.
Affected by bump – If enabled, the curvature shader will be calculated based on bump-mapped normals. If disabled, bump-mapping is not considered when computing curvature shader.
Distance texture – This allows you to use a texture map or shader for the transition between the calculated curvature and flat surface.
Base color (no curvature)
Level – This is the intensity (also considered as the visibility) of the color.
Color – This parameter defines the color of the surface where it is flat.
Texture – Defines the texture map or shader that is used for the base color.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength – Controls the intensity of the texture map or shader that is being used.
Convex surface color
Level – This is the intensity (also considered as the visibility) of the color.
Color – This parameter defines the color of the surface where it is convex. (The outward color)
Texture – Defines the texture map or shader that is used for the convex surface color.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength – Controls the intensity of the texture map or shader that is used.
Concave surface color
Level – This is the intensity (also considered as the visibility) of the color.
Color – This parameter defines the color of the surface where it is concave. (The inward color)
Texture – Defines the texture map or shader used for the concave surface color.
Mix mode – Controls the blending mode of the texture map or shader.
Mix strength – Controls the intensity of the texture map or shader that is used.
Examples
Use Corona Curvature Shaders as masks with Corona Layered Material to combine different metals for different details of a mesh.
Corona Curvature Shader: Example 1
Corona Curvature Shader: Example 2
Difference between Corona AO shader and Corona Curvature shader
Example A
In this example, you can see that the AO and Curvature shaders look very similar to each other.
Example B
In this example, you can clearly notice the difference between the AO and Curvature shaders.