Corona Curvature Shader - C4D
The Corona Curvature Shader 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.
Where to find it?
We can create a Corona Curvature Shader in Cinema4D node material editor:
In Node material editor right-click in any material view then go to Map>Corona>CoronaCuvature.
What options does it offer?
Parameters of the Corona Curvature Shader
1. Max sample: How many samples to use. Higher values will render slower but will produce clean results faster. Even low values will eventually converge to a clean image.
2. Ray directionality: This value defines how focused the curvature effect is around the most concave and convex areas. With a low value, all directions will be considered equally. Increasing the value causes the shader to be more dependent on whether the direction directly above the surface is occluded or not. For example :
Ray Directionality = 0
Ray Diectionality = 0.5
Ray Directionality = 1
3. Max distance: Determines the radius that the curvature traces. Can be used to match curvature between big and small objects.
4. Base color: This parameter defines the color of the surface where it is flat.
5. Convex(Outward) color: This parameter defines the color of the surface where it is convex.
6. Concave(Inward) color: This parameter defines the color of the surface where it is concave
Using Corona Curvature Shader:
The Corona Curvature Shader can be used directly as a material’s diffuse color, or we can use it as a mask.
NOTE: You can set one of the three available swatches to a specific color and the other two swatches to another color if you wish to only show the flat areas of the mesh, only the concave areas, or only the convex areas.
1. Corona Curvature Shader Set to show white color on Convex areas only:
2. Corona Curvature Shader Set to show white color on Concave areas only:
Corona Curvature Shader use-case scenarios:
Using as a multi-color map: Create a Corona Curvature Shader, then assign different colors or texture maps as required. Then put it in the slot in which you need the colors, for example, diffuse color:
Using as a grayscale mask:
Create a Corona Curvature Shader, then use white and black values in the base, convex, and concave slots of the Corona Curvature Shader to produce a grayscale mask which can be used as a mask to hide or reveal the convex (outwards) or concave (inwards) areas of the mesh. For example, as a layer mask in Corona Layered Material or opacity slot of a Corona Physical material:
Example 1: Here we used Corona Curvature Shaders as masks with Corona Layered material to combine different metals for different details of a mesh.
Gold metal shows Convex(Outward) details, Copper shows Concave(Inward) details and Green Metal shows base flat surfaces
Example 2: Here we used Corona Curvature Shader as a mask with Corona Layered material to combine different metals for different details of a mesh.
Rusted metal shows Convex(Outward) and Concave(Inward) details and Grey Metal shows base flat surfaces
Example 3: Here we used Corona Curvature Shader as a diffuse map to get different colors on a flat surface and convex and concave details.
Material Setup: We used Corona Curvature Shader in the diffuse slot of a Corona Physical Material and assigned it to the mesh. Then we assigned a blue texture map in the Base color and a red texture map in Convex color and a green texture map in the Concave color of the Corona Curvature Shader.
Corona Curvature VS Corona AO Map :
In this example you can see that the AO and Curvature Shaders look very similar to each other.
In this example you can very clearly notice the difference between the AO and Curvature Shaders.
You can read more about the Corona AO Shader here.