In games there is something called LOD´s ( levels of detail ) that is you can have many different versions of the model , one that is veryx detail one that is medium detail and one that is very low detail.
Have you got any experiences with wich is the best workflow ? to start with a low detail model and then add detail or the other way around ? there is also the trouble of UV maps getting messed up.
also do you know any good simplifier that keeps the topology of the mesh pretty much clean ? decimate makes the topology pretty much messed up.
For work flow, all I can suggest is “not the one I picked” :D. I had the same experience you did with Decimate (not too useful) and so was trying to remove detail by hand, easy enough except that my UVs get messed up.
If possible, you might try the other way around: model with low poly first, and then add subsurf modifiers for the higher detail models. If that will work for your modeling task, I think it might be easier than the other way around. Adding more detail seems to leave UVs in good shape, but taking it away damages them horribly.
I am no expert either. But Blender has interesting tool called Mulires. With it, you can go back and forth between low to high poly with just a push of a button! It is used mainly for Normal Mapping but it should work fine for what you want to do.
The best way to do LOD meshes (at least the ones that are required to be separately modeled - some engines do continuous LOD on the fly & do not require separate models) is to do them by hand starting with highest res version, already UV mapped & textured.
No algorithm is going to know where to keep edges and where to toss 'em… that takes a human brain.
Cull your edges/verts away from joint areas… you’ll still need some extra resolution at the joints for animation (another thing no algorithm is going to consider.) As you cull your verts, check your mesh often zoomed way out to the approx. distance that the LOD will pop in… make sure you’re not culling out geometry needed to maintain the objects profile/silhouette at a distance… you want the player to still be able to recognize the model, even from far away.
Also, avoid deleting edges that comprise UV boundaries. This will make it much easier to UV map the low res LOD’s since you can put the UV seams in the same places as on the hi-res version. It really doesn’t take very long to UV map a lo res LOD onto a pre-exist texture (the one from the hi-res version.) It doesn’t have to be perfect… these are LOD’s … they will only be seen from a distance and UV seams aren’t very noticeable on a model that is only a couple hundred pixels high
