mirror of
https://github.com/facebookresearch/pytorch3d.git
synced 2025-08-02 03:42:50 +08:00
124bb5e391
Summary: Collection of spelling things, mostly in docs / tutorials. Reviewed By: gkioxari Differential Revision: D26101323 fbshipit-source-id: 652f62bc9d71a4ff872efa21141225e43191353a
76 lines
2.7 KiB
Markdown
76 lines
2.7 KiB
Markdown
---
|
|
sidebar_label: Loading from file
|
|
hide_title: true
|
|
---
|
|
|
|
# Meshes and IO
|
|
|
|
The Meshes object represents a batch of triangulated meshes, and is central to
|
|
much of the functionality of PyTorch3D. There is no insistence that each mesh in
|
|
the batch has the same number of vertices or faces. When available, it can store
|
|
other data which pertains to the mesh, for example face normals, face areas
|
|
and textures.
|
|
|
|
Two common file formats for storing single meshes are ".obj" and ".ply" files,
|
|
and PyTorch3D has functions for reading these.
|
|
|
|
## OBJ
|
|
|
|
Obj files have a standard way to store extra information about a mesh. Given an
|
|
obj file, it can be read with
|
|
|
|
```
|
|
verts, faces, aux = load_obj(filename)
|
|
```
|
|
|
|
which sets `verts` to be a (V,3)-tensor of vertices and `faces.verts_idx` to be
|
|
an (F,3)- tensor of the vertex-indices of each of the corners of the faces.
|
|
Faces which are not triangles will be split into triangles. `aux` is an object
|
|
which may contain normals, uv coordinates, material colors and textures if they
|
|
are present, and `faces` may additionally contain indices into these normals,
|
|
textures and materials in its NamedTuple structure. A Meshes object containing a
|
|
single mesh can be created from just the vertices and faces using
|
|
```
|
|
meshes = Meshes(verts=[verts], faces=[faces.verts_idx])
|
|
```
|
|
|
|
If there is texture information in the `.obj` it can be used to initialize a
|
|
`Textures` class which is passed into the `Meshes` constructor. Currently we
|
|
support loading of texture maps for meshes which have one texture map for the
|
|
entire mesh e.g.
|
|
|
|
```
|
|
verts_uvs = aux.verts_uvs[None, ...] # (1, V, 2)
|
|
faces_uvs = faces.textures_idx[None, ...] # (1, F, 3)
|
|
tex_maps = aux.texture_images
|
|
|
|
# tex_maps is a dictionary of {material name: texture image}.
|
|
# Take the first image:
|
|
texture_image = list(tex_maps.values())[0]
|
|
texture_image = texture_image[None, ...] # (1, H, W, 3)
|
|
|
|
# Create a textures object
|
|
tex = Textures(verts_uvs=verts_uvs, faces_uvs=faces_uvs, maps=texture_image)
|
|
|
|
# Initialise the mesh with textures
|
|
meshes = Meshes(verts=[verts], faces=[faces.verts_idx], textures=tex)
|
|
```
|
|
|
|
The `load_objs_as_meshes` function provides this procedure.
|
|
|
|
## PLY
|
|
|
|
Ply files are flexible in the way they store additional information. PyTorch3D
|
|
provides a function just to read the vertices and faces from a ply file.
|
|
The call
|
|
```
|
|
verts, faces = load_ply(filename)
|
|
```
|
|
sets `verts` to be a (V,3)-tensor of vertices and `faces` to be an (F,3)-
|
|
tensor of the vertex-indices of each of the corners of the faces. Faces which
|
|
are not triangles will be split into triangles. A Meshes object containing a
|
|
single mesh can be created from this data using
|
|
```
|
|
meshes = Meshes(verts=[verts], faces=[faces])
|
|
```
|