Mesh Slicing

This example demonstrates how to slice a mesh with multiple planes using COMPAS CGAL.

Key Features:

• Loading STL mesh files
• Creating multiple slice planes from bounding box
• Slicing mesh with multiple planes
• Converting slice results to polylines
• Visualization with semi-transparent mesh and slice curves

from pathlib import Path

import numpy as np
from compas.datastructures import Mesh
from compas.geometry import Plane
from compas.geometry import Point
from compas.geometry import Polyline
from compas.geometry import Vector
from compas_viewer import Viewer
from compas_viewer.config import Config

from compas_cgal.slicer import slice_mesh

# =============================================================================
# Get Mesh from STL
# =============================================================================

FILE = Path(__file__).parent.parent.parent / "data" / "3DBenchy.stl"
benchy = Mesh.from_stl(FILE)

V, F = benchy.to_vertices_and_faces()

# =============================================================================
# Get Slice planes from the bounding box
# =============================================================================

bbox = benchy.aabb()
normal = Vector(0, 0, 1)
planes = []
for i in np.linspace(bbox.zmin, bbox.zmax, 50):
    plane = Plane(Point(0, 0, i), normal)
    planes.append(plane)

# =============================================================================
# Slice
# =============================================================================

slicer_polylines = slice_mesh((V, F), planes)

polylines = []
for polyline in slicer_polylines:
    points = []
    for point in polyline:
        points.append(Point(*point))
    polylines.append(Polyline(points))

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

config = Config()

viewer = Viewer(config=config)

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

for polyline in polylines:
    viewer.scene.add(polyline, linewidth=2, show_points=False)

viewer.show()