def test_polygon_mesh_slicer():
print("Testing Polygon_mesh_slicer...")
P = get_poly()
slicer = Polygon_mesh_slicer(P)
slice = Polylines()
slicer.slice(Plane_3(1, 0, 0, -0.5), slice)
assert (slice.size() == 1)
assert (len(slice[0]) != 0)
def _slice(zpos):
plane_query = Plane_3(Point_3(0, 0, zpos), vec)
intersections = list()
tree.all_intersections(plane_query, intersections)
if callback is not None:
callback("Found intersections at %3.3f z" % zpos)
return (zpos,
self._intersection_to_segments(intersections, accuracy))
intersection = tree.any_intersection(segment_query)
if not intersection.empty():
# gets intersection object
op = intersection.value()
object = op[0]
if object.is_Point_3():
print("intersection object is a point")
# computes all intersections with segment query (as pairs object - primitive_id)
intersections = []
tree.all_intersections(segment_query, intersections)
# computes all intersected primitives with segment query as primitive ids
primitives = []
tree.all_intersected_primitives(segment_query, primitives)
# constructs plane query
vec = Vector_3(0.0, 0.0, 1.0)
plane_query = Plane_3(a, vec)
# computes first encountered intersection with plane query
# (generally a segment)
intersection = tree.any_intersection(plane_query)
if not intersection.empty():
# gets intersection object
op = intersection.value()
object = op[0]
if object.is_Segment_3():
print("intersection object is a segment")
pts = []
pts.append(Point_3(0, 0, 0))
pts.append(Point_3(0, 1, 0))
pts.append(Point_3(1, 1, 0))
pts.append(Point_3(1, 0, 0))
pts.append(Point_3(0, 0, 1))
pts.append(Point_3(0, 1, 1))
pts.append(Point_3(1, 1, 1))
pts.append(Point_3(1, 0, 1))
res = Polyhedron_3()
CGAL_Convex_hull_3.convex_hull_3(pts, res)
print("convex hull has ", res.size_of_vertices(), " vertices")
print("is strongly convex: ", CGAL_Convex_hull_3.is_strongly_convex_3(res))
planes = []
planes.append(Plane_3(-1, 0, 0, 0))
planes.append(Plane_3(1, 0, 0, -1))
planes.append(Plane_3(0, -1, 0, 0))
planes.append(Plane_3(0, 1, 0, -1))
planes.append(Plane_3(0, 0, -1, 0))
planes.append(Plane_3(0, 0, 1, -1))
res.clear()
CGAL_Convex_hull_3.halfspace_intersection_3(planes, res)
print("halfspace intersection has ", res.size_of_vertices(), " vertices")
def AABB_polyhedron_facet_intersection():
"""Facet intersection mode
AABB (axis aligned bounding boxes)
The AABB is a data structure for finding intersections
We do the following:
* Create a polyhedron
* Create a segment and plane
* Find the intersection of segment and plane with polyhedron
"""
from CGAL.CGAL_Kernel import Point_3
from CGAL.CGAL_Kernel import Vector_3
from CGAL.CGAL_Kernel import Plane_3
from CGAL.CGAL_Kernel import Segment_3
from CGAL.CGAL_Polyhedron_3 import Polyhedron_3
from CGAL.CGAL_AABB_tree import AABB_tree_Polyhedron_3_Facet_handle
p = Point_3(1.0, 0.0, 0.0)
q = Point_3(0.0, 1.0, 0.0)
r = Point_3(0.0, 0.0, 1.0)
s = Point_3(0.0, 0.0, 0.0)
polyhedron = Polyhedron_3()
polyhedron.make_tetrahedron(p, q, r, s)
# construct the AABB tree
tree = AABB_tree_Polyhedron_3_Facet_handle(polyhedron.facets())
# construct segment query
a = Point_3(-0.2, 0.2, -0.2)
b = Point_3(1.3, 0.2, 1.3)
segment_query = Segment_3(a,b)
# do the intersection of segment with polyhedron
if tree.do_intersect(segment_query):
print("Intersection")
else:
print("No intersection")
# compute the number of intersections with the segment
print(tree.number_of_intersected_primitives(segment_query), " intersection")
# compute first intersection with segment
intersection = tree.any_intersection(segment_query)
if not intersection.empty():
# get the intersection object
op = intersection.value()
object = op[0]
if object.is_Point_3():
print("intersection object is a point")
# compute all intersections with the segment query
primitives = []
tree.all_intersected_primitives(segment_query,primitives)
# construct plane query
vec = Vector_3(0, 0, 1.0)
plane_query = Plane_3(Point_3(0, 0, 0.5), vec)
# compute first intersection of tetrahedron and plane
intersection = tree.any_intersection(plane_query)
if not intersection.empty():
op = intersection.value()
object = op[0]
if object.is_Segment_3():
print("intersection object is a segment")