How to load texture file mtl into python?

[xiaodongww]

Hi, thanks for your great job.

In my work, I want to extract the vertex coordinates and vertex color of the reconstructed mesh using python. However, I find it is not convenient to extract the vertex color. I have tried Open3D and it does not work.

I tried to load the *.obj using Open3D as follows:

import numpy as np
import open3d as o3d
import cv2

mesh = o3d.io.read_triangle_mesh('mesh.refined.obj', True)
img = cv2.imread('mesh.refined_0.png')
mesh.textures = [o3d.geometry.Image(img)]

vertex_colors = np.asarray(mesh.vertex_colors)  # what we want
o3d.visualization.draw_geometries([mesh])  # check if texture loaded correctly

The texture is not correctly loaded. The result seems messy.
It should looks like this

However, the actual visualization is as follows:

What tool do you use to generate the mesh.refined.mtl and mesh.refined_0.png? Do you have any idea how to extract vertex colors using python?

Any suggestion will be helpful. Thanks a lot.

[vincentcartillier]

I also had issues with loading the mesh with texture in Open3D.
Mostly my problem was that I am using open3d==0.9 because I am still under ubuntu 16 and this doesn't seem to be supported.
However I believe with newer versions it should work.

Anyhow, using trimesh should do

import trimesh

mesh = trimesh.load(mesh_filename)
mesh_colors = mesh.visual.to_color()

points = mesh.verties
colors = mesh_colors.vertex_colors

I just tried it with trimesh 3.9.43