normal map workflow question

sir-knight

I'm sort of on the brink of jumping into normal mapping... really need to get a new pc and play with ut3 ... but I could be months away from that looking at my budget. Anyways, digressing...

I see a lot of talk about base meshes and how you should always model them in quads because when you sculpt them, they will map properly. I've done some reading on the subject, but not a whole lot, as right now I am working on another project in my spare time.


So just to make sure I understand the workflow process, this is how I should set myself up?

Model some nice base meshes to give myself an easy starting point in the future for sculpts

Do I need to unwrap these?

Go into mudbox or zbrush and sculpt to my heart's delight

Here's what I'm most unclear about.

Judging by what I see in some base meshes, would/should I use the base mesh to apply the normal map to, or should I model a brand new optimized mesh with proper edge/face looping for good deformations?

unwrap new low poly mesh.

bake it all together

do some delicious texturing

rig it.

bring it into game of choice?

MoP

Yes, sounds like you're on the right track.

Your basemesh should be 100% quads, and try to avoid "poles" of 5+ edges running into each other since that can lead to "pinching" in the model when sculpting. Keep the quads a fairly uniform density over the body, and be clever about adding more detail where it will be necessary (eyes, ears, nose etc), since otherwise you will end up subdividing your mesh far more than necessary just to get enough polys to sculpt detail into some areas.

I would probably unwrap my base mesh, since while you won't necessarily need it, if you want to do polypainting in zbrush and bake that down to a texture for the highpoly, that will need UV coordinates, so it's probably better to get it done early (since it doesn't have to be an awesome / optimised unwrap, it can be pretty quick and sloppy, just minimum seams and distortion), then you won't have to worry about trying to uv-map your basemesh later and trying to morph it or merge it with your sculpt.

With regards to making a new optimised mesh with good optimisation and loops for deforming in animation, I find the easiest way to start is with the 2nd subdivision level of your sculpt (or in some cases, the base mesh itself is a fine starting point). Then you can just collapse edge loops or cut in new edges to add/remove detail as necessary.

Then uv-map that new mesh (again, if you unwrapped the basemesh, then half of this work will already be done for you) and bake your sculpt and any highpoly texture work down to your new lowpoly mesh.

East

Very good suggestions from MoP. Personally I don't care too much about avoiding tris. You don't want to cover your entire basemesh in them, but a few here and there aren't going to totally ruin your model. You do get pinching artifacts, but there are ways to fix that -- both while sculpting, and in post by editing your normal map by hand (which you probably will end up doing anyway).

Also, when doing your basemesh, look ahead and see how many polygons your computer can comfortably handle in ZBrush. If your sweet spot is 9 million polygons, you don't want to end up at 12 million when going to your final subdivision level. Sure, you can hide parts of your model, but I find that inconvenient, so I try to keep each subtool in the scene inside my computer's comfort zone.

For exporting polypainted textures I normally use the automatic UVs in ZBrush, but doing it as MoP does it, by hand, is probably the prefered way. Although I don't notice any real difference when doing either way on my meshes/textures.

Again, I do some things differently than MoP, but it doesn't mean I think my way is better, just different. He's the more experienced/talented one of the two of us anyway, so if I were you I'd heed his advice first

MoP

I just UV the basemesh 'cos it takes no time at all, and means that you don't just have to polypaint the sculpt, you can actually work on the texture for the sculpt in Photoshop if you want, since the layout isn't unworkable manually (as auto UVs in zbrush would be).

Plus it saves a step later when you build your lowpoly using either the initial basemesh or the lower sub-d levels of the sculpt, since you don't really have to UV anything, just relax a bit where necessary and move chunks around.

Regarding triangles in basemeshes - I really would avoid them where possible, I am pretty sure there are some commands/procedures/tools in ZBrush and Mudbox which really hate triangles (ie. they may make it more likely that the program will crash, or that it will do something unexpected).

That's just from my experience though, I'm sure it's perfectly feasible to work fine with tris in your basemesh, I just like to play it safe to avoid possible pain later

East

As for tris in your basemesh, I never have that in ZBrush. It's not optimal, but I always subdivide my basemesh once before bringing it into ZBrush, removing all the triangles. This isn't perfect since the resulting 3-pole can and usually does cause pinching, but it is acceptable in areas where it matters less (armpits, top of head that's going to be covered with hair anyway, etc).

Again, take MoP's advice, since it's hard to get rid of bad habits once you pick them up.

Just for the record, and why I never UV my basemeshes, I always retopologise. That is, I never go back and use the basemesh to create my low polygon model when it is a sculpt model. Instead I create a new mesh on top of the high polygon one, following as closely as possible, which is going to be the in-game mesh asset. This mesh I lay out UVs for, of course

This is very subjective, though, and there are instances when your basemesh is going to be so detailed and alike your high poly, that it would just be a waste to retopologise.

sir-knight

thanks guys, that will quell the overwhelming desire I have to move on in 3d for the time being :P


Got to get through my storyboarding project first... maybe by then I'll have cleared the credit cards and be able to get a new setup to jump back in.

So many fun things to do... so little time...