Definitely the best result for low polygon creation I've seen. Great job!
Still triangles rather than polygons, but we are getting closer.
The end goal should be:
1) Polygons, mostly 4 sided, rather than triangles.
2) Edge smoothness/creases to separate hard coders from soft corners. (Which when combined with polygons enables SubD support: https://graphics.pixar.com/opensubdiv/docs/subdivision_surfa...)
3) UV for textures that are aligned with the natural flow of textures on those components.
4) Repeating textures (although sometimes not) that work with the UVs and combine to create PBR textures. (Getting closer all the time: https://gvecchio.com/stablematerials/)
After the above works, I think people should move on to inferring proper CAD models from an image. Basically infer all the constraints and the various construction steps.
why are polygons preferred over triangles?
It's much easier and cleaner to subdivide quads to refine shapes when modeling. For example, you can split the quads along an entire edge to get a new clean edge for manipulation (ex. to bevel it). If you try to do the same with triangles, you get a jagged mess.
This might be a naive/stupid question, but wouldn't it be relatively easy to merge triangles in the same plane into polygons automatically? (I suppose few triangles from this process would be in the same plane maybe?)
If they’re actually in the same plane, yes. But that’s rarely the case except in hard surface modeling.
Besides, merging them unintelligently still doesn’t necessarily form clean edge loops, which are required for good model topology.
I believe also quads also deform better during animation.
They are not. Polygons are a terrible representation since unlike triangles they do not cleanly represent a unique planar surface. With more than 3 points you will always have an ambiguity (or several) about which (numerical) plane corresponds to the actual face. For some graphics applications this may or may not matter much, but it is very important for anything using the mesh for physical computation.
Co-planar quads will always subdivide into two coplanar tris. That's the crux on why the modeling work flow works. The GPU is going to turn it into triangles anyway as long as a few fundamental rules with indices are up kept, so you're mostly getting the best of both worlds here.
I feel like maybe CAD would be easier? You only need represent form/edges, rather than meet all the requirements that you have for using a model for games/rendering.
Are you describing NURBs?