Just like Bug 407431, it would be lovely to have a thumbnailer for .obj files. .obj is a common open, text-based, software-independent file format for 3D models. https://en.wikipedia.org/wiki/Wavefront_.obj_file
Since support for /usr/share/thumbnailers was added last year,[1] this can be accomplished by using an external thumbnailer, for example F3D which works with a few other 3D formats too.[2] [1] https://planet.kde.org/akseli-lahtinen-aks-2024-08-08-kio-thumbnailer-support/ [2] https://f3d.app/doc/user/DESKTOP_INTEGRATION.html