Game Modeling Asset Questions

Ken Bock

I have a few questions for game modeling processes that I just never could clarify, partially because I've heard different things for each question from different tutorials.

1) I've heard from different people and different tutorials that when modeling for games you put your low poly mesh on the outside, conferencing the high poly mesh and others say to have it opposite with the high on the outside and low underneath because the rays (when baking NM and AO etc) will go through the high and then bake onto the low. So any idea which is it and which gives the best maps or is it another preference thing?

2) Another thing I've wondered is do you smooth both the high and low poly? or just the high? Like when you have edges that you want to be sharp you add additional edges on either side of it so when it smooths its stays sharp and doesn't smooth out. I never really knew so I've always done both the high and the low like that.

3) One last quick one. Is it if your High Poly mesh has holes in it or could that lead to issues such as artifacts in you NM, AO etc?



I'm just really trying to wrap my head around the whole game modeling process. I do know a lot of things come down to preference but if you know of any tips or videos that really explain and inform about game modeling processes etc(particularly with Modo for modeling) I would greatly appreciated.

Thanks

CheeseOnToast

1. Both wrong. Your low poly can have parts which are inside the high poly or outside, or both. The normal map baker is looking for differences in direction, not height. Simply put, model your low poly to be close to the the high poly, but don't worry about intersections.

2. Just the high poly. And smoothing is a means to an end ie. getting a smooth-looking source mesh. You don't always have to subdivide to achieve this.

3. Your highpoly can have holes in it but it's best to put some kind of backing behind it, or just make "fake" holes. Check out some of the normal mapping threads for a better explanation.

Visceral

2: however you need to assign smoothing groups to your low poly to make a bake as good as possible.

Ken Bock

So the low poly wont effect the baking in anyway since some parts are in and out of the high poly? Would it be because you have your high poly designated as the source mesh?

CheeseOnToast

It's pretty simple. When a ray is cast from the low poly it's looking for the nearest surface of the highpoly to compare normals with, whether that's inside or outside the lowpoly mesh. There's usually options to tweak this behaviour if you want the ray to grab info from the last surface it hits, for example. Generally the default is what you'll need though. I haven't used Modo for baking, but I reckon it'll be similar to Maya/Max/Xnormal.