Add code

ifield/data/common/mesh.py

@@ -0,0 +1,48 @@
+from math import pi
+from trimesh import Trimesh
+import numpy as np
+import os
+import trimesh
+import trimesh.transformations as T
+
+DEBUG = bool(os.environ.get("IFIELD_DEBUG", ""))
+
+__doc__ = """
+Here are some helper functions for processing data.
+"""
+
+def rotate_to_closest_axis_aligned_bounds(
+        mesh       : Trimesh,
+        order_axes : bool    = True,
+        fail_ok    : bool    = True,
+        ) -> np.ndarray:
+    to_origin_mat4, extents = trimesh.bounds.oriented_bounds(mesh, ordered=not order_axes)
+    to_aabb_rot_mat4 = T.euler_matrix(*T.decompose_matrix(to_origin_mat4)[3])
+
+    if not order_axes:
+        return to_aabb_rot_mat4
+
+    v  = pi / 4 * 1.01 # tolerance
+    v2 = pi / 2
+
+    faces = (
+        (0, 0),
+        (1, 0),
+        (2, 0),
+        (3, 0),
+        (0, 1),
+        (0,-1),
+    )
+    orientations = [ # 6 faces x 4 rotations per face
+        (f[0] * v2, f[1] * v2, i * v2)
+        for i in range(4)
+        for f in faces]
+
+    for x, y, z in orientations:
+        mat4 = T.euler_matrix(x, y, z) @ to_aabb_rot_mat4
+        ai, aj, ak = T.euler_from_matrix(mat4)
+        if abs(ai) <= v and abs(aj) <= v and abs(ak) <= v:
+            return mat4
+
+    if fail_ok: return to_aabb_rot_mat4
+    raise Exception("Unable to orient mesh")