Added files from local to remote

tetrahedralize_triangles.py

+import numpy as np
+
+def fix_triangle_normals(V, F):
+
+    for i in range(len(F)):
+
+        face = F[i]
+        vertices = V[face,:]
+
+        V1 = np.pad(V[1] - V[0], (0, 1))
+        V2 = np.pad(V[2] - V[1], (0, 1))
+        if np.cross(V1, V2)[2] < 0:
+            F[i] = F[i][::-1]
+
+    return F
+
+def check_vertex_ordering(V):
+    return np.dot(np.cross(V[1] - V[0], V[2] - V[0]), V[3] - V[0]) > 0
+
+def tetrahedralize(V_tri, F, z0, z1):
+
+    if z0 > z1:
+        z0, z1 = z1, z0
+
+    F = fix_triangle_normals(V_tri, F)
+
+    N = len(V_tri)
+    V_tet = np.concatenate([
+        np.pad(V_tri, ((0,0), (0,1)), constant_values=z0), 
+        np.pad(V_tri, ((0,0), (0,1)), constant_values=z1)
+        ])
+
+    T = []
+
+    for face in F:
+        new_tet = [face[0], face[1],     face[2],     face[0] + N]
+        while not check_vertex_ordering(V_tet[new_tet]):
+            np.random.shuffle(new_tet)
+        T.append(new_tet)
+        new_tet = [face[1], face[2],     face[0] + N, face[1] + N]
+        while not check_vertex_ordering(V_tet[new_tet]):
+            np.random.shuffle(new_tet)
+        T.append(new_tet)
+        new_tet = [face[2], face[0] + N, face[1] + N, face[2] + N]
+        while not check_vertex_ordering(V_tet[new_tet]):
+            np.random.shuffle(new_tet)
+        T.append(new_tet)
+
+    return V_tet, T
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