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Summary: Set up landing page, docs page, and html versions of the ipython notebook tutorials. Pull Request resolved: https://github.com/fairinternal/pytorch3d/pull/11 Reviewed By: gkioxari Differential Revision: D19730380 Pulled By: nikhilaravi fbshipit-source-id: 5df8d3f2ac2f8dce4d51f5d14fc336508c2fd0ea
73 lines
2.6 KiB
Markdown
73 lines
2.6 KiB
Markdown
---
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sidebar_label: Loading from file
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hide_title: true
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---
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# Meshes and IO
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The Meshes object represents a batch of triangulated meshes, and is central to
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much of the functionality of pytorch3d. There is no insistence that each mesh in
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the batch has the same number of vertices or faces. When available, it can store
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other data which pertains to the mesh, for example face normals, face areas
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and textures.
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Two common file formats for storing single meshes are ".obj" and ".ply" files,
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and pytorch3d has functions for reading these.
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## OBJ
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Obj files have a standard way to store extra information about a mesh. Given an
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obj file, it can be read with
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```
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verts, faces, aux = load_obj(filename)
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```
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which sets `verts` to be a (V,3)-tensor of vertices and `faces.verts_idx` to be
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an (F,3)- tensor of the vertex-indices of each of the corners of the faces.
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Faces which are not triangles will be split into triangles. `aux` is an object
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which may contain normals, uv coordinates, material colors and textures if they
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are present, and `faces` may additionally contain indices into these normals,
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textures and materials in its NamedTuple structure. A Meshes object containing a
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single mesh can be created from just the vertices and faces using
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```
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meshes = Meshes(verts=[verts], faces=[faces.verts_idx])
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```
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If there is texture information in the `.obj` it can be used to initialize a
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`Textures` class which is passed into the `Meshes` constructor. Currently we
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support loading of texture maps for meshes which have one texture map for the
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entire mesh e.g.
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```
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verts_uvs = aux.verts_uvs[None, ...] # (1, V, 2)
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faces_uvs = faces.textures_idx[None, ...] # (1, F, 3)
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tex_maps = aux.texture_images
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# tex_maps is a dictionary of {material name: texture image}.
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# Take the first image:
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texture_image = list(tex_maps.values())[0]
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texture_image = texture_image[None, ...] # (1, H, W, 3)
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# Create a textures object
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tex = Textures(verts_uvs=verts_uvs, faces_uvs=faces_uvs, maps=texture_image)
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# Initialise the mesh with textures
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meshes = Meshes(verts=[verts], faces=[faces.verts_idx], textures=tex)
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```
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## PLY
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Ply files are flexible in the way they store additional information, pytorch3d
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provides a function just to read the vertices and faces from a ply file.
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The call
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```
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verts, faces = load_ply(filename)
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```
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sets `verts` to be a (V,3)-tensor of vertices and `faces` to be an (F,3)-
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tensor of the vertex-indices of each of the corners of the faces. Faces which
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are not triangles will be split into triangles. A Meshes object containing a
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single mesh can be created from this data using
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```
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meshes = Meshes(verts=[verts], faces=[faces])
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```
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