The other is Remix 3D library, similar to old Sketchup Warehouse, its a library of 3D models free to download (i think) and edit.
BUT there's a "gap" between these tools and the major software (games, Celestia tools to convert to formats the program reads, Celestia itself) which is 3D: the formats.
Paint 3D can read .3mf, .stl, .ply, .obj, .glb and .fbx, and can write to .3mf, .glb and .fbx. and Remix 3D seems to natively have .glb models.
My question is: can Celestia implement support for one of these formats (at least .obj due to versatility) natively for celestial bodies/spacecraft?
I think this would be far useful for newbie modders, the simple fact we can get ridden of Blender to convert (with some distortions depending of the format) the models to a more common format, then using some other convertor to .cmod, aside some interesting models like spacecrafts are available in remix 3d library, which could be used in celestia.
PS.: Other format interesting to implement is Collada. Mostly because Spore can export creatures and vehicles into this format
