trimesh_principal_curvature

compas_rhino.geometry.trimesh_principal_curvature(M)[source]

Compute the principal curvature of a triangle mesh.

Parameters:
Mtuple[sequence[[float, float, float] | compas.geometry.Point], sequence[[int, int, int]]]

A mesh represented by a list of vertices and a list of faces.

Returns:
list[float]

The max curvature per vertex.

list[float]

The min curvature per vertex.

Notes

Description: The discrete principal curvature is computed by mean curvature, Gaussian curvature, and vertex area.

Notation Convention:
  • \(\kappa^1_i, \kappa^2_i\) - The max principal curvature and the min principal curvature at the vertex i

  • \(H_i\) - the discrete mean curvature at vertex i

  • \(K_i\) - the discrete Gaussian curvature at vertex i

  • \(A_i\) - the area of the dual cell centered at vertex i

Formula:

\[\kappa^1_i, \kappa^2_i = \frac{H_i}{A_i}\pm\sqrt{\left( \,\frac{H_i}{A_i}\right)\,^2-\frac{K_i}{A_i}}\]

References

[1]

Formula of Discrete Principal Curvature available at Keenan Crane’s lecture, 03:16-07:11, at https://youtu.be/sokeN5VxBB8

Examples

Make a mesh from scratch >>> from compas.geometry import Sphere >>> sphere = Sphere([1, 1, 1], 1) >>> sphere = Mesh.from_shape(sphere, u=30, v=30) >>> sphere.quads_to_triangles() >>> M = sphere.to_vertices_and_faces()

Compute the discrete principal curvature >>> H = trimesh_principal_curvature(M)