I try to do detect the intersections of a ray with a polygon using pyvista. In this case the polygon is a cube. The cube is defined by points in 2d and then extruded. Why does this simple example where a ray is intersecting with the cube detect only one intersection?
import numpy as np
import pyvista as pv
points = [(0, 0), (0, 10), (10, 10), (10, 0)]
def points_2d_to_poly(points, z):
"""Convert a sequence of 2d coordinates to polydata with a polygon."""
faces = [len(points), *range(len(points))]
poly = pv.PolyData([p + (z,) for p in points], faces=faces)
return poly
polygon = points_2d_to_poly(points, 0.0)
polygon_extruded = polygon.extrude((0, 0, 6.0), capping=True)
poly_surface = polygon_extruded.extract_surface()
poly_mesh = poly_surface.triangulate()
# Define line segment
start = [5, 2, -10]
stop = [5, 2, 10]
# Perform ray trace
points, ind = poly_mesh.ray_trace(start, stop, first_point=False)
# Create geometry to represent ray trace
ray = pv.Line(start, stop)
intersection = pv.PolyData(points)
# Render the result
p = pv.Plotter()
p.add_mesh(poly_mesh, show_edges=True, opacity=0.5, color="w", lighting=False, label="Test Mesh")
p.add_mesh(ray, color="blue", line_width=5, label="Ray Segment")
p.add_mesh(intersection, color="maroon", point_size=25, label="Intersection Points")
p.add_legend()
p.show()
