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Submesh 3/n: Add submeshing functionality
Summary: Copypasting the docstring: ``` Split a mesh into submeshes, defined by face indices of the original Meshes object. Args: face_indices: Let the original mesh have verts_list() of length N. Can be either - List of length N. The n-th element is a list of length num_submeshes_n (empty lists are allowed). Each element of the n-th sublist is a LongTensor of length num_faces. - List of length N. The n-th element is a possibly empty padded LongTensor of shape (num_submeshes_n, max_num_faces). Returns: Meshes object with selected submeshes. The submesh tensors are cloned. Currently submeshing only works with no textures or with the TexturesVertex texture. Example: Take a Meshes object `cubes` with 4 meshes, each a translated cube. Then: * len(cubes) is 4, len(cubes.verts_list()) is 4, len(cubes.faces_list()) is 4, * [cube_verts.size for cube_verts in cubes.verts_list()] is [8, 8, 8, 8], * [cube_faces.size for cube_faces in cubes.faces_list()] if [6, 6, 6, 6], Now let front_facet, top_and_bottom, all_facets be LongTensors of sizes (2), (4), and (12), each picking up a number of facets of a cube by specifying the appropriate triangular faces. Then let `subcubes = cubes.submeshes([[front_facet, top_and_bottom], [], [all_facets], []])`. * len(subcubes) is 3. * subcubes[0] is the front facet of the cube contained in cubes[0]. * subcubes[1] is a mesh containing the (disconnected) top and bottom facets of cubes[0]. * subcubes[2] is a clone of cubes[2]. * There are no submeshes of cubes[1] and cubes[3] in subcubes. * subcubes[0] and subcubes[1] are not watertight. subcubes[2] is. ``` Reviewed By: bottler Differential Revision: D35440657 fbshipit-source-id: 8a6d2d300ce226b5b9eb440688528b5e795195a1
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@ -1556,6 +1556,115 @@ class Meshes:
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else:
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raise ValueError("Meshes does not have textures")
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def submeshes(
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self,
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face_indices: Union[
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List[List[torch.LongTensor]], List[torch.LongTensor], torch.LongTensor
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],
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) -> "Meshes":
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"""
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Split a batch of meshes into a batch of submeshes.
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The return value is a Meshes object representing
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[mesh restricted to only faces indexed by selected_faces
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for mesh, selected_faces_list in zip(self, face_indices)
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for faces in selected_faces_list]
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Args:
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face_indices:
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Let the original mesh have verts_list() of length N.
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Can be either
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- List of lists of LongTensors. The n-th element is a list of length
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num_submeshes_n (empty lists are allowed). The k-th element of the n-th
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sublist is a LongTensor of length num_faces_submesh_n_k.
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- List of LongTensors. The n-th element is a (possibly empty) LongTensor
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of shape (num_submeshes_n, num_faces_n).
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- A LongTensor of shape (N, num_submeshes_per_mesh, num_faces_per_submesh)
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where all meshes in the batch will have the same number of submeshes.
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This will result in an output Meshes object with batch size equal to
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N * num_submeshes_per_mesh.
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Returns:
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Meshes object of length `sum(len(ids) for ids in face_indices)`.
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Submeshing only works with no textures or with the TexturesVertex texture.
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Example 1:
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If `meshes` has batch size 1, and `face_indices` is a 1D LongTensor,
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then `meshes.submeshes([[face_indices]]) and
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`meshes.submeshes(face_indices[None, None])` both produce a Meshes of length 1,
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containing a single submesh with a subset of `meshes`' faces, whose indices are
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specified by `face_indices`.
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Example 2:
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Take a Meshes object `cubes` with 4 meshes, each a translated cube. Then:
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* len(cubes) is 4, len(cubes.verts_list()) is 4, len(cubes.faces_list()) 4,
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* [cube_verts.size for cube_verts in cubes.verts_list()] is [8, 8, 8, 8],
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* [cube_faces.size for cube_faces in cubes.faces_list()] if [6, 6, 6, 6],
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Now let front_facet, top_and_bottom, all_facets be LongTensors of
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sizes (2), (4), and (12), each picking up a number of facets of a cube by
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specifying the appropriate triangular faces.
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Then let `subcubes = cubes.submeshes([[front_facet, top_and_bottom], [],
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[all_facets], []])`.
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* len(subcubes) is 3.
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* subcubes[0] is the front facet of the cube contained in cubes[0].
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* subcubes[1] is a mesh containing the (disconnected) top and bottom facets
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of cubes[0].
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* subcubes[2] is cubes[2].
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* There are no submeshes of cubes[1] and cubes[3] in subcubes.
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* subcubes[0] and subcubes[1] are not watertight. subcubes[2] is.
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"""
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if not (
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self.textures is None or type(self.textures).__name__ == "TexturesVertex"
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):
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raise ValueError(
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"Submesh extraction only works with no textures or TexturesVertex."
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)
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if len(face_indices) != len(self):
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raise ValueError(
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"You must specify exactly one set of submeshes"
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" for each mesh in this Meshes object."
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)
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sub_verts = []
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sub_faces = []
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for face_ids_per_mesh, faces, verts in zip(
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face_indices, self.faces_list(), self.verts_list()
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):
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for submesh_face_ids in face_ids_per_mesh:
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faces_to_keep = faces[submesh_face_ids]
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# Say we are keeping two faces from a mesh with six vertices:
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# faces_to_keep = [[0, 6, 4],
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# [0, 2, 6]]
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# Then we want verts_to_keep to contain only vertices [0, 2, 4, 6]:
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vertex_ids_to_keep = torch.unique(faces_to_keep, sorted=True)
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sub_verts.append(verts[vertex_ids_to_keep])
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# Now, convert faces_to_keep to use the new vertex ids.
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# In our example, instead of
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# [[0, 6, 4],
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# [0, 2, 6]]
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# we want faces_to_keep to be
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# [[0, 3, 2],
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# [0, 1, 3]],
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# as each point id got reduced to its sort rank.
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_, ids_of_unique_ids_in_sorted = torch.unique(
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faces_to_keep, return_inverse=True
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)
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sub_faces.append(ids_of_unique_ids_in_sorted)
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return self.__class__(
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verts=sub_verts,
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faces=sub_faces,
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)
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def join_meshes_as_batch(meshes: List[Meshes], include_textures: bool = True) -> Meshes:
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"""
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@ -233,6 +233,46 @@ def to_sorted(mesh: Meshes) -> "Meshes":
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return other
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def init_cube_meshes(device: str = "cpu"):
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# Make Meshes with four cubes translated from the origin by varying amounts.
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verts = torch.FloatTensor(
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[
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[0, 0, 0],
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[1, 0, 0], # 1->0
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[1, 1, 0], # 2->1
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[0, 1, 0], # 3->2
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[0, 1, 1], # 3
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[1, 1, 1], # 4
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[1, 0, 1], # 5
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[0, 0, 1],
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],
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device=device,
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)
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faces = torch.FloatTensor(
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[
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[0, 2, 1],
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[0, 3, 2],
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[2, 3, 4], # 1,2, 3
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[2, 4, 5], #
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[1, 2, 5], #
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[1, 5, 6], #
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[0, 7, 4],
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[0, 4, 3],
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[5, 4, 7],
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[5, 7, 6],
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[0, 6, 7],
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[0, 1, 6],
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],
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device=device,
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)
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return Meshes(
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verts=[verts, verts + 1, verts + 2, verts + 3],
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faces=[faces, faces, faces, faces],
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)
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class TestMeshes(TestCaseMixin, unittest.TestCase):
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def setUp(self) -> None:
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np.random.seed(42)
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@ -1257,6 +1297,106 @@ class TestMeshes(TestCaseMixin, unittest.TestCase):
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yes_normals.offset_verts_(torch.FloatTensor([1, 2, 3]).expand(12, 3))
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self.assertFalse(torch.allclose(yes_normals.verts_normals_padded(), verts))
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def test_submeshes(self):
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empty_mesh = Meshes([], [])
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# Four cubes with offsets [0, 1, 2, 3].
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cubes = init_cube_meshes()
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# Extracting an empty submesh from an empty mesh is allowed, but extracting
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# a nonempty submesh from an empty mesh should result in a value error.
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self.assertTrue(mesh_structures_equal(empty_mesh.submeshes([]), empty_mesh))
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self.assertTrue(
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mesh_structures_equal(cubes.submeshes([[], [], [], []]), empty_mesh)
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)
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with self.assertRaisesRegex(
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ValueError, "You must specify exactly one set of submeshes"
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):
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empty_mesh.submeshes([torch.LongTensor([0])])
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# Check that we can chop the cube up into its facets.
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subcubes = to_sorted(
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cubes.submeshes(
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[ # Do not submesh cube#1.
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[],
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# Submesh the front face and the top-and-bottom of cube#2.
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[
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torch.LongTensor([0, 1]),
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torch.LongTensor([2, 3, 4, 5]),
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],
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# Do not submesh cube#3.
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[],
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# Submesh the whole cube#4 (clone it).
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[torch.LongTensor(list(range(12)))],
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]
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)
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)
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# The cube should've been chopped into three submeshes.
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self.assertEquals(len(subcubes), 3)
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# The first submesh should be a single facet of cube#2.
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front_facet = to_sorted(
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Meshes(
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verts=torch.FloatTensor([[[0, 0, 0], [1, 0, 0], [1, 1, 0], [0, 1, 0]]])
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+ 1,
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faces=torch.LongTensor([[[0, 2, 1], [0, 3, 2]]]),
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)
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)
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self.assertTrue(mesh_structures_equal(front_facet, subcubes[0]))
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# The second submesh should be the top and bottom facets of cube#2.
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top_and_bottom = Meshes(
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verts=torch.FloatTensor(
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[[[1, 0, 0], [1, 1, 0], [0, 1, 0], [0, 1, 1], [1, 1, 1], [1, 0, 1]]]
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)
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+ 1,
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faces=torch.LongTensor([[[1, 2, 3], [1, 3, 4], [0, 1, 4], [0, 4, 5]]]),
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)
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self.assertTrue(mesh_structures_equal(to_sorted(top_and_bottom), subcubes[1]))
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# The last submesh should be all of cube#3.
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self.assertTrue(mesh_structures_equal(to_sorted(cubes[3]), subcubes[2]))
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# Test alternative input parameterization: list of LongTensors.
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two_facets = torch.LongTensor([[0, 1], [4, 5]])
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subcubes = to_sorted(cubes.submeshes([two_facets, [], two_facets, []]))
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expected_verts = torch.FloatTensor(
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[
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[[0, 0, 0], [0, 1, 0], [1, 0, 0], [1, 1, 0]],
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[[1, 0, 0], [1, 0, 1], [1, 1, 0], [1, 1, 1]],
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[[2, 2, 2], [2, 3, 2], [3, 2, 2], [3, 3, 2]],
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[[3, 2, 2], [3, 2, 3], [3, 3, 2], [3, 3, 3]],
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]
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)
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expected_faces = torch.LongTensor(
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[
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[[0, 3, 2], [0, 1, 3]],
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[[0, 2, 3], [0, 3, 1]],
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[[0, 3, 2], [0, 1, 3]],
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[[0, 2, 3], [0, 3, 1]],
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]
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)
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expected_meshes = Meshes(verts=expected_verts, faces=expected_faces)
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self.assertTrue(mesh_structures_equal(subcubes, expected_meshes))
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# Test alternative input parameterization: a single LongTensor.
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triangle_per_mesh = torch.LongTensor([[[0]], [[1]], [[4]], [[5]]])
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subcubes = to_sorted(cubes.submeshes(triangle_per_mesh))
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expected_verts = torch.FloatTensor(
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[
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[[0, 0, 0], [1, 0, 0], [1, 1, 0]],
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[[1, 1, 1], [1, 2, 1], [2, 2, 1]],
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[[3, 2, 2], [3, 3, 2], [3, 3, 3]],
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[[4, 3, 3], [4, 3, 4], [4, 4, 4]],
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]
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)
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expected_faces = torch.LongTensor(
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[[[0, 2, 1]], [[0, 1, 2]], [[0, 1, 2]], [[0, 2, 1]]]
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)
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expected_meshes = Meshes(verts=expected_verts, faces=expected_faces)
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self.assertTrue(mesh_structures_equal(subcubes, expected_meshes))
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def test_compute_faces_areas_cpu_cuda(self):
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num_meshes = 10
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max_v = 100
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