Write OBJ can not include triangle normals

[thomas134340]

Hi, I'm trying to convert a point cloud to mesh via BPA, and need the output in obj format. However it says "write obj can not include triangle normals", and the output is stored incorrectly. My current solution is to save it as .ply and then convert it to .obj via other software. Does anyone know why this problem is appearing, and how I could solve it?

[RecursiveAV]

I have this issue also - is there a solution?

[DenisTome]

Same here

[kongsgard]

Does setting mesh.triangle_normals = o3d.utility.Vector3dVector([]) fix the issue?

Complete example:

import open3d as o3d
mesh = o3d.geometry.TriangleMesh.create_box()

mesh.compute_triangle_normals()
o3d.io.write_triangle_mesh("mesh.obj", mesh) # Gives the warning "[Open3D WARNING] Write OBJ can not include triangle normals.", but still writes the file.

mesh.triangle_normals = o3d.utility.Vector3dVector([])
o3d.io.write_triangle_mesh("mesh.obj", mesh) # Writes the file without any warnings.

[tlemarec]

Does setting mesh.triangle_normals = o3d.utility.Vector3dVector([]) fix the issue?

Complete example:

import open3d as o3d
mesh = o3d.geometry.TriangleMesh.create_box()

mesh.compute_triangle_normals()
o3d.io.write_triangle_mesh("mesh.obj", mesh) # Gives the warning "[Open3D WARNING] Write OBJ can not include triangle normals.", but still writes the file.

mesh.triangle_normals = o3d.utility.Vector3dVector([])
o3d.io.write_triangle_mesh("mesh.obj", mesh) # Writes the file without any warnings.

Same issue here. The above response is relevant only when creating an obj with no normal. What about when the normals are needed in the obj ?

[reyanshsolis]

Writing Triangle Normal is currently not supported in WriteTriangleMesh for OBJ format. mesh.triangle_normals = o3d.utility.Vector3dVector([]) -> This removes the normals, that's why we don't get the warning.

I have added this to feature_request. Thanks

[jackieyung]

WriteTriangleMesh

Hi, @reyanshsolis, did you solve this problem? I also want to save normals value into the obj file, but it failed. the version of my open3d is 0.15.1.

[josephko91]

I'm facing same issue. Just checking to see if there are any updates.

[StarsTesla]

Same here, I think this is an essenial attr.