Error loading ShapeNet meshes with texture

[janbechtold]

Describe the bug
When loading specific ShapeNet meshes with Open3D > 0.11, the process ends after printing 'Not a JPEG file: starts with 0x89 0x50'.
In contrast, Open3D version 0.8.0 with python 3.7.9 returns a mesh.

To Reproduce
Steps to reproduce the behavior:
From within your ShapeNetCore.v2 directory...

1. cd '02801938/d9f0f7cff584b60d826faebfb5cddf3c/models'
2. source activate yourcondaenv
3. python

import open3d as o3d
o3d.io.read_triangle_mesh('model_normalized.obj')

4. See error: Not a JPEG file: starts with 0x89 0x50

(same for this model: 03467517/2cbc0faddf227502bbc745a3524d966b/models)

Expected behavior

1. A mesh is returned automatically without texture, or
2. An option to not load the texture, or
3. A way to catch this in python

Environment (please complete the following information):

• Operating system: RHEL8
• Python version: 3.8
• Open3D version: 0.13.0
• Is this remote workstation?: yes
• How did you install Open3D?: conda

[wangyePHD]

In fact, I also meet the same bug when I used the API read_triangle_mesh in the Shapenet-v1.

[wangyePHD]

And I think that maybe the .obj file has some problem.

[Steven-xzr]

The same issue with 02691156/de45798ef57fe2d131b4f9e586a6d334

[juc023]

How can we solve it? I simply removed that particular data..

[Saafke]

It seems the error is with the texture files. If you put the .obj file in a separate folder, it loads in Open3D correctly.

If you need the textures, take a look at this answer: https://blender.stackexchange.com/questions/89010/materials-not-applied-after-importing-obj-shapenet/188192#188192 . You can convert the buggy .obj model from ShapeNet to a .glb model using https://github.com/CesiumGS/obj2gltf.

[yjang2]

The same issue with 02691156/31b201b7346e6cd15e9e2656aff7dd5b

[tomas-aftalion]

For more context on the ShapeNet bug (Stanford url download): it comes from png files having jpg extensions, nothing wrong with the obj file by itself. As mentioned by @Saafke, gets solved by moving to different directory.

In terms of possible fix to o3d: I am able to load the images with matplotlib though. It might be that o3d uses file extensions rather than first bytes to determine file type.

[saurabheights]

@tomas-aftalion yeah, you are right.

https://gist.github.com/leommoore/f9e57ba2aa4bf197ebc5

0x89 0x50 is png magic number.

And open3d does read based on file extension in the name and not using magic number.

Open3D/cpp/open3d/io/ImageIO.cpp

Line 23 in c7718fd

file_extension_to_image_read_function{