volume mesh additional cell types bindings

src/polyscope/volume_mesh.py

@@ -287,7 +287,19 @@ def register_volume_mesh(
     material: str | None = None,
     transparency: float | None = None,
 ) -> VolumeMesh:
-    """Register a new volume mesh"""
+    """
+    Register a new volume mesh.
+
+    Pass index arrays of tets (N,4), hexes (N,8) or mixed_cells (N,8) to specify the cell connectivity.
+
+    The mixed_cells argument supports a mixture of tets, hexes, prisms, and pyramid elements; for each
+    row of indices, right-pad with -1 indices when not needed for that element type, for example a
+    pyramid cell row might be [72, 33, 86, 91, 15, -1, -1, -1].
+
+    It is not supported to specify both tets/hexes and the general mixed_cells; in this case, just pass
+    all cells as mixed_cells. You may pass both the tets and hexes arrays simultaneously, if so the cells
+    are presumed to be ordered with all tetrahedral cells coming first, then hexahedral cells.
+    """
 
     if not psb.is_initialized():
         raise RuntimeError("Polyscope has not been initialized")

test/tests/test_all.py

@@ -1816,6 +1816,20 @@ def test_add_mixed(self):
         # cells[-5:,4:] = -1 # clear out some rows at end
         # ps.register_volume_mesh("test_mesh3", self.generate_verts(), hexes=self.generate_tets())
 
+    def test_add_prisms_pyramids_mixed(self):
+        np.random.seed(777)
+        n_pts = 10
+        # prisms: (N,6) padded to (N,8) with -1 in last 2 cols
+        prism_cells = np.random.randint(0, n_pts, size=(n_pts, 8))
+        prism_cells[:, 6:] = -1
+        # pyramids: (N,5) padded to (N,8) with -1 in last 3 cols
+        pyramid_cells = np.random.randint(0, n_pts, size=(n_pts, 8))
+        pyramid_cells[:, 5:] = -1
+        cells = np.concatenate([prism_cells, pyramid_cells], axis=0)
+        ps.register_volume_mesh("test_mesh3", self.generate_verts(), mixed_cells=cells)
+        ps.show(3)
+        ps.remove_all_structures()
+
     def test_options(self):
         p = ps.register_volume_mesh("test_mesh", self.generate_verts(), self.generate_tets())