Because you asked me: 3D OBJ files from a single 2D image.

[parkdalegardener]

OK; I've received a few questions from folk having 2D files they were interested in making into 3D objects. I've told you it isn't there yet but it's coming. It still isn't perfect but here you go. Check this out.
InstantMesh from TencentARC

Now I'm not peak performance ATM as we all know so I'll make this as useful as possible.

First up the Hugging Face Demo so you can try it out yourselves. https://huggingface.co/spaces/TencentARC/InstantMesh

Next up is the GitHub code repository. This is the official code from TencentARC https://github.com/TencentARC/InstantMesh

Finally this is the Model itself available on Hugging Face https://huggingface.co/TencentARC/InstantMesh

Read the Model Card or the GitHub page to get more of an overview if you can't figure it out from the demo.

For the tech minded the GitHub code will help you get it running locally providing you have the machine to run it.

The Model link is for those with a local install of StableDiffusion already running and are comfortable writing a plugin.

[Aelin]

Just the first link is very interesting for who can't have it on local machine
Of course, objects faces are triangulation, but I guess it's manageable to put in 'squares' if necessary, after the cleaning of the model in a modelization program.

[parkdalegardener]

Rig the output OBJs? Not a chance yet. The mesh is a mess but it will get better.

It's really for props ATM but people ask me for 2d character to 3d mesh and this is the best out there right now. That's why the link to the code page so one can see the changes they implement as they improve.

Now one could use a few of the better output images to tune the OBJs. Won't help with rigging unless you start with an "A" or "T" pose for the final OBJ though. Haven't tried.

[Aelin]

I rig nothing (not for me yet), I think for props that's a great thing. And even if a .obj isn't perfect, it can be a 'pattern' for a work in progress.