Corona Curvature Map

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.

Base color – Defines the color of the surface where it is flat.

Convex color – The outward color that defines the color of the surface where it is convex.

Concave color – Inwards color that defines the color of the surface where it is concave.

Max distance – Determines the radius that the curvature traces. Can be used to match curvature between big and small objects.

Ray directionality – How strongly the tested rays will be 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 samples – How many samples to use. A higher value renders slower but produces clean results faster. Even low values will eventually converge to a clean image.

Color spread – Changes how rapidly the convex/concave colors replace the flat color as curvature increases. Increasing this value means the result will have more of the convex/concave colors mixed in.

In this example you can see that the AO and Curvature maps look very similar to each other.

In this example you can very clearly notice the difference between the AO and Curvature maps.