Files
igl/python/203_CurvatureDirections.py
T

62 lines
1.3 KiB
Python
Executable File

import igl
V = igl.eigen.MatrixXd();
F = igl.eigen.MatrixXi();
igl.read_triangle_mesh("../tutorial/shared/fertility.off", V, F);
# Alternative discrete mean curvature
HN = igl.eigen.MatrixXd()
L = igl.eigen.SparseMatrixd()
M = igl.eigen.SparseMatrixd()
Minv = igl.eigen.SparseMatrixd()
igl.cotmatrix(V,F,L)
igl.massmatrix(V,F,igl.MASSMATRIX_TYPE_VORONOI,M)
igl.invert_diag(M,Minv)
# Laplace-Beltrami of position
HN = -Minv*(L*V)
# Extract magnitude as mean curvature
H = HN.rowwiseNorm()
# Compute curvature directions via quadric fitting
PD1 = igl.eigen.MatrixXd()
PD2 = igl.eigen.MatrixXd()
PV1 = igl.eigen.MatrixXd()
PV2 = igl.eigen.MatrixXd()
igl.principal_curvature(V,F,PD1,PD2,PV1,PV2)
# Mean curvature
H = 0.5*(PV1+PV2)
viewer = igl.viewer.Viewer()
viewer.data.set_mesh(V, F)
# Compute pseudocolor
C = igl.eigen.MatrixXd()
igl.parula(H,True,C)
viewer.data.set_colors(C)
# Average edge length for sizing
avg = igl.avg_edge_length(V,F)
# Draw a blue segment parallel to the minimal curvature direction
red = igl.eigen.MatrixXd([[0.8,0.2,0.2]])
blue = igl.eigen.MatrixXd([[0.2,0.2,0.8]])
viewer.data.add_edges(V + PD1*avg, V - PD1*avg, blue)
# Draw a red segment parallel to the maximal curvature direction
viewer.data.add_edges(V + PD2*avg, V - PD2*avg, red)
# Hide wireframe
viewer.core.show_lines = False
viewer.launch();