Interesting convo I had with some industry experts at polycount about smoothing groups.
Quote: "<Stradigos> I'm trying to explain to someone that using different smoothing groups on your model is not a good idea. Doesn't it add more geometry somehow? Why exactly don't you want to?
<III_Demon> its not a huge deal
<III_Demon> you just dont wanna go nuts with it
<III_Demon> 'smoothing groups' are just an interface.. they're an obnoxious layer on top of the actual meat of the thing
<III_Demon> whats actually going on is separate vertex normals per face
<Stradigos> what happens to them when you bring it into a game engine
<III_Demon> maya handles it on a per edge basis
<Stradigos> so would that mean two normals per vertex?
<III_Demon> each sharp edged vertex becomes multiple verts, if the game engine doesnt handle it properly. depends on the format.
<III_Demon> best case, everything is handled properly, and you have multiple normals per vert.. face vertex normals or whatever they're called in your specific thing
<gcmp> meshes get seperated by angle so it becomes more complex but sometimes it's needed with some low poly stuff
<III_Demon> worst case, the format doesnt know how to handle it, so it splits the verts into separate ones, which can create wacky seams on your edges, and definitely creates more geometry
<III_Demon> its not the end of the world.. you just wanna avoid lots of 'hard edges' or whatever, if you're using a system that doesnt handle them properly
<Stradigos> alright, thanks for clearing that up
<Stradigos> one more question
<Stradigos> if you baking, you definitely want to have one smoothing group though right?
<III_Demon> it figures into normal mapping, and thats another layer of complexity
<Stradigos> so then short answer yes?
<gcmp> well I had that when exporting and reimporting a mesh from a popular game engine, every face that had different smoothing on was an element to be able to handle the supplemental game engine lighting
<III_Demon> eh... there we go with the complexity. =] generally, yes, if you can get away with it, you just wanna leave smoothing groups alone entirely. put everything in one smoothing group and leave it that way
<III_Demon> some engines kinda require the opposite, for normal mapping.. but they handle that in the engine, and i have no idea wtf i'm talking about if i go any deeper than that.
<Stradigos> lol, thanks
Stradigos> I think using smoothing groups is fugly
<Stradigos> I hate it
<Stradigos> I'd rather texture it and normal map it
<III_Demon> at this point its just left over from obsolete days
<Stradigos> yeah
<III_Demon> yeah. normal mapping is the better solution
<III_Demon> and/or higher poly counts
<III_Demon> if you can jack the poly count high enough, theres never any need for sharp edges at all"
"If I have seen a little further it is by standing on the shoulders of Giants" - Isaac Newton
-Computer Animation Major @Baker.edu-
