Questions regarding 3D characters for game engines: animation, weightpaint, topology, texturing
Hello,
Please help me with these questions.
(Or is there a tutorial for performance / animation questions for game characters?)
Software in use: Zbrush, Substance Painter, Blender and Unity (VR Game)
Task:
So
I am asked to create characters. This includes a
variety of clothes, adional assets (Ex. a book, a gun, etc.) , face
animation (blendshapes), and additional animations (cheering, sleeping
etc.).
So
far I only did assets for games, like "items you can hold in your hand
and furniture", so most of the questions did not come up anyway (and the
game developers I worked for, simply had no idea about 3d assets
anyway).
Regarding Topology and Triangulation:
Now
this is an interesting question for me, because everyone keeps telling
"Quads only" for characters (or mostly quads) because it messes up
animations.
But I will export it to unity:
I will use normal maps, baked in Substance painter - so I will need a
pretriangulated asset. Do I use the triangulated mesh for: rigging, weightpainting, creating blendshapes, animation and importing into unity?
Blendshapes:
I should detach the head, because blendshapes take a lot of performance (and they count all verts for calculation).
This is problematic for me. The character might have very different clothes: underwear, a shirt, a jacket.
Where would i detach the head? Just right at the neck? Necks can bend, I am afraid it could break the mesh, leaving open space, or look somehow bad with normal maps / AO.
Clothes vs Topology:
How should i deal with topology? Do
i have to keep the whole body (or most of it) below the clothes?
Because I never can tell, which top will be combined to which bottom (as
players can choose clothes as they wish), I cannot tell if it is a
short skirt or long jeans. I am afraid, that...
a) it would be bad for performance and file size to keep unnecesarry polygons. Example: Unity would have to bend the arm, and my jacket on top of that.
b) The polygons of the nude body could intersect with the polygons of the clothes. Especially troublesome for a VR game.
How to deal with this?
Clothes vs UV space:
Is there anything to be said against putting several items of clothing (for example 4 tops together) on one UV? As long as I keep a reasonable texel density...
I also plan to mirror some clothes (for example, a shirt), to 1/2 the UV space it will use, by 1:1 overlapping. But I am afraid it will interfere with the normal and ambient occlusion maps... Would it be useful, to only import 1/2 of the mesh into substance painter and only bake this half?
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