pyblenderSDIC.meshes.TriangleMesh3D.compute_triangle_normals

TriangleMesh3D.compute_triangle_normals() → None

Compute the normals of the triangles in the mesh.

The normals are computed as the cross product of the edges of each triangle. The result is stored in the triangle_normals attribute as a NumPy array of shape (M, 3), where M is the number of triangles and each row contains the normal vector of a triangle.

The normals are normalized to have unit length.

\[N = \frac{(P_2 - P_1) \times (P_3 - P_1)}{\| (P_2 - P_1) \times (P_3 - P_1) \|}\]

where \(P_1\), \(P_2\), and \(P_3\) are the vertices of the triangle, and \(\times\) is the cross product.

from pyblenderSDIC.mesh import TriangleMesh3D

# Create a TriangleMesh3D instance
mesh = TriangleMesh3D(vertices=..., triangles=...)

# Compute the normals of the triangles
mesh.compute_triangle_normals()

# The normals are now available in the `triangle_normals` attribute
mesh.triangle_normals