Houdini 16.5 Nodes VOP nodes

Curvature VOP node

Computes surface curvature.

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This VOP computes the amount of surface curvature, with white in convex areas, black in concave areas and 50% gray in flat areas. This is useful for masking wear like scratches and dents, which often happen on raised edges.

Note

Derivatives for polygonal meshes are not continuous, which results in a "faceted" look. To evaluate smooth curvature for meshes you should enable the smooth toggle.

Inputs

Point

Input surface point. If not connected the global variable of the same name is used.

Normal

Input surface normal. If not connected the global variable of the same name is used.

Parameters

Mode

Selects between various curvature properties. Gaussian is the product of the principal curvatures. Mean is half the sum of the principal curvatures.

Space

Selects the output space of the curvature value. -1 to 1 uses a mid-point of 0.0, with convex areas from 0.0 > 1.0 and concave areas from -1.0 > 0.0. 0 to 1 uses a mid-point of 0.5, with convex areas from 0.5 > 1.0 and concave areas from 0.0 > 0.5.

Smooth

Enables smooth evaluation of curvature for polygonal meshes.

Tolerance

Determines how small a change in curvature is considered when shading the gradient.

Scale

Multiplies the output curvature value. If you are seeing any curvature shading you should increase this value until the gradient is visible.

Bias

This acts as a contrast control over the gradient, with values higher and lower than 0.5 resulting in more and less contrast.

Bias Map

Varies the bias by a pattern. This is useful for breaking up smooth areas of the gradient. It should be mapped with a greyscale pattern, in the /nodes/vop/0,1 range.

Outputs

Curvature

Output curvature value.

VOP nodes