Is there a tool/command that can automatically unwrap/generate UV for a given 3D model?
We have an .obj file that comes from a 3D camera. But it comes without UVs.
I heard that MeshLab can do it.
Is there a command-line command for MeshLab or a similar command-line tool to achieve this?
I also found https://www.instantuv.org/, but it loses a lot of detail in the process.
There are a number of auto meshing alternatives which can generate UVs (most of which will also do auto retopology which if your obj is from a 3D camera you will most likely need pretty badly) and MeshLab, MeshMixer, Instant Mesh all leap to mind. Most 3D DCC (Digital Content Creation) tools (Modo, Maya, 3DS, Blender, Cinema 4D) have their own discrete UVing toolsets, and many of those now have pre-canned UV unwrap commands - most of which you should be able to invoke from the command line.
The risk you run with auto meshing / auto UV methods is that if your initial geometry isn't already pretty well topologised, the resulting UVs will be... challenging... to work with.
FWIW: Instant Mesh is pretty darn amazing, and can help you get some close-to-manually retpologised quickly, which then makes whatever approach you choose for auto UVing far more likely to succeed.
Instant UV (the link you had provided) looks very interesting - I didn't see on the public-facing info anything which led me to conclude that the UVs generated by their auto-UVing SDK were somehow low detail - but I did see that one of the retopology demonstration figurines seemed to push pretty far down the detail scale (the rivets which were fully half-spherical in the original scan mesh had been downsampled so far that they became tetrahedra) however I looked briefly at the online docs for the CLI mesh reduction tool, and it sure looked like you could tune the degree of compression - and more crucially, it looked like it had an automated setup for baking normal and colour maps from the high-res mesh to the lower - which depending upon your final use-case for this model might be a huge time saver.
What I didn't see there was whether you can choose tris or quads for remeshing - cos for some of us, quads are far preferred - both for general sub-D work and for ease of animation... but I know that Instant Mesh does give me that choice.
Hope some of this helps.
