In Meshroom 2023.3 MeshDecimate ignores nbVertices setting

[guizy67]

Describe the bug In Meshroom-2023.3.0 on linux (ubuntu 22.04 and 24.04), when I set nbVertices to a specific value, the resulting mesh does not match the number of vertices. Typically there is a factor of 2 or 3 times more in my case.

I am using a template file from the command line of meshroom_batch. Extract of the template file:

        "MeshDecimate_1": {
            "nodeType": "MeshDecimate",
            "position": [
                2192,
                -184
            ],
            "inputs": {
                "input": "{MeshDenoising_1.output}",
                "nbVertices": 32000
            }
        }

To Reproduce Steps to reproduce the behavior:

1. Create a template .mg file containing the inputs for mesh decimate, with fixed nbVertices
2. Run meshroom_batch -p template.mg --images imagefolder
3. Verify number of vertices and number of faces using Meshlab (or other software)
4. Number of vertices does not match the value specified in the template

Expected behavior In version 2023.1.0 the number of vertices exactly match the value given in the template file. This is the expected behavior. In version 2023.3.0 they are completely different.

Desktop (please complete the following and other pertinent information):

• OS: Ubuntu lts 22.04 and 2.04
• Python version: 3.10 and 3.12
• Meshroom version: release 2023.3.0
  • Binary version 2023.3.0

[guizy67]

This was an incorrect interpretation from my part. The MeshDecimate node works as expected, but the Texturing node does not. That is the one 'ignoring' the reduction in the number of faces. I have created a new issue for the Texturing: https://github.com/alicevision/Meshroom/issues/2496