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Refactor facet direction code

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gumyr 2023-08-13 11:59:34 -04:00
parent bc6189f448
commit 64f056c2af
1 changed files with 13 additions and 41 deletions
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54
src/build123d/mesher.py
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@ -95,14 +95,14 @@ from OCP.BRepBuilderAPI import (
BRepBuilderAPI_MakeSolid,
BRepBuilderAPI_Sewing,
)
from OCP.BRepGProp import BRepGProp_Face
from OCP.BRepMesh import BRepMesh_IncrementalMesh
from OCP.GeomAPI import GeomAPI_ProjectPointOnSurf
from OCP.gp import gp_Pnt, gp_Vec
from OCP.gp import gp_Pnt
import OCP.TopAbs as ta
from OCP.TopLoc import TopLoc_Location
from py_lib3mf import Lib3MF
from build123d.build_enums import MeshType, Unit
from build123d.geometry import Color, Vector
from build123d.geometry import Color
from build123d.topology import Compound, Shape, Shell, Solid, downcast
@ -254,26 +254,6 @@ class Mesher:
properties.append(property_dict)
return properties
@staticmethod
def _is_facet_forward(
points: tuple[gp_Pnt, gp_Pnt, gp_Pnt], shape_center: Vector
) -> bool:
"""Is the facet facing inward or outward"""
# Create the facet
polygon_builder = BRepBuilderAPI_MakePolygon(*points, Close=True)
face_builder = BRepBuilderAPI_MakeFace(polygon_builder.Wire())
facet = face_builder.Face()
# Find its center & normal
surface = BRep_Tool.Surface_s(facet)
projector = GeomAPI_ProjectPointOnSurf(points[0], surface)
u_val, v_val = projector.LowerDistanceParameters()
center_gp_pnt = gp_Pnt()
normal_gp_vec = gp_Vec()
BRepGProp_Face(facet).Normal(u_val, v_val, center_gp_pnt, normal_gp_vec)
facet_normal = Vector(normal_gp_vec)
# Does the facet normal point to the center
return facet_normal.get_angle(shape_center - Vector(center_gp_pnt)) > 90
@staticmethod
def _mesh_shape(
ocp_mesh: Shape,
@ -293,9 +273,9 @@ class Mesher:
ocp_mesh_vertices = []
triangles = []
offset = 0
for ocp_face in ocp_mesh.faces():
for facet in ocp_mesh.faces():
# Triangulate the face
poly_triangulation = BRep_Tool.Triangulation_s(ocp_face.wrapped, loc)
poly_triangulation = BRep_Tool.Triangulation_s(facet.wrapped, loc)
trsf = loc.Transformation()
# Store the vertices in the triangulated face
node_count = poly_triangulation.NbNodes()
@ -305,8 +285,10 @@ class Mesher:
ocp_mesh_vertices.append(pnt)
# Store the triangles from the triangulated faces
facet_reversed = facet.wrapped.Orientation() == ta.TopAbs_REVERSED
order = [1, 3, 2] if facet_reversed else [1, 2, 3]
for tri in poly_triangulation.Triangles():
triangles.append([tri.Value(i) + offset - 1 for i in [1, 2, 3]])
triangles.append([tri.Value(i) + offset - 1 for i in order])
offset += node_count
return ocp_mesh_vertices, triangles
@ -314,7 +296,6 @@ class Mesher:
def _create_3mf_mesh(
ocp_mesh_vertices: list[tuple[float, float, float]],
triangles: list[list[int, int, int]],
shape_center: Vector,
):
"""Create the data to create a 3mf mesh"""
# Create a lookup table of face vertex to shape vertex
@ -335,18 +316,9 @@ class Mesher:
# Create triangle point list
triangles_3mf = []
for vertex_indices in triangles:
triangle_points = (
gp_pnts[vert_table[vertex_indices[0]]],
gp_pnts[vert_table[vertex_indices[1]]],
gp_pnts[vert_table[vertex_indices[2]]],
)
order = (
[0, 2, 1]
if not Mesher._is_facet_forward(triangle_points, shape_center)
else [0, 1, 2]
)
# order = [2, 1, 0] # Creates an invalid mesh
mapped_indices = [vert_table[i] for i in [vertex_indices[i] for i in order]]
mapped_indices = [
vert_table[i] for i in [vertex_indices[i] for i in range(3)]
]
# Remove degenerate triangles
if len(set(mapped_indices)) != 3:
continue
@ -425,7 +397,7 @@ class Mesher:
# Create 3mf mesh inputs
vertices_3mf, triangles_3mf = Mesher._create_3mf_mesh(
ocp_mesh_vertices, triangles, b3d_shape.center()
ocp_mesh_vertices, triangles
)
# Build the mesh