Mesh Skeletonization

This example demonstrates how to compute the geometric skeleton of a triangle mesh using COMPAS CGAL.

Key Features:

  • Loading and transforming OFF mesh files

  • Mesh subdivision using Loop scheme

  • Skeleton computation using mean curvature flow

  • Visualization of mesh and skeleton polylines

../_images/example_skeletonization.png 
import math
from pathlib import Path

from compas.datastructures import Mesh
from compas.geometry import Polyline
from compas.geometry import Rotation
from compas.geometry import Scale
from compas.geometry import Translation
from compas_viewer import Viewer
from line_profiler import profile

from compas_cgal.skeletonization import mesh_skeleton


@profile
def main():
    """Skeletonize a mesh."""

    input_file = Path(__file__).parent.parent.parent / "data" / "elephant.off"

    rotation_x = Rotation.from_axis_and_angle([1, 0, 0], math.radians(60))
    rotation_y = Rotation.from_axis_and_angle([0, 1, 0], math.radians(5))
    rotation = rotation_y * rotation_x
    scale = Scale.from_factors([5, 5, 5])
    translation = Translation.from_vector([0, 0, 2])

    mesh = Mesh.from_off(input_file).transformed(translation * rotation * scale)
    # mesh = mesh.subdivided("loop")
    v, f = mesh.to_vertices_and_faces(triangulated=True)

    skeleton_edges = mesh_skeleton((v, f))

    polylines = []
    for start_point, end_point in skeleton_edges:
        polyline = Polyline([start_point, end_point])
        polylines.append(polyline)

    return mesh, polylines


mesh, polylines = main()

# ==============================================================================
# Visualize
# ==============================================================================

viewer = Viewer()
viewer.renderer.camera.target = [0, 0, 1.5]
viewer.renderer.camera.position = [-5, -5, 1.5]

viewer.scene.add(mesh, opacity=0.5, show_points=False)

for polyline in polylines:
    viewer.scene.add(polyline, linewidth=5, show_points=True)

viewer.show()