Correspondance with Aren Voorhees

Aren Voorhees, aka Artistic Vendetta, is a professional 3d game character artist who's currently working as the Lead Character Artist at 'Day 1 Studios' on F.E.A.R. 3 for Xbox, PS3 and PC. Be sure to check out his website!

Below you'll see my questions and the answers he provided on character development.

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Simon Chuptys wrote:

Greetings,

We are students at the KULeuven (Belgium) and in our free time, we're working on our own game. We're reaching the stage where we are in need of a character (finally) :) but since it's the first time I have to model/scuplt one, i'm having some questions about the process:

What workflow is used? From what i found around the internet, it looks something like this:

  1. low poly model with uv-layout
  2. sculpting and exctraction of displacement/diffuse/specular/… maps
  3. retopology and re-unwrap uv-coordinates
  4. add it all together and start rigging

Now the question i had about this is, why is it necessary to do the retopology? Can't i use the basic mesh from the sculpting and add the maps there? And if retopology is necessary, how do i ensure the UV-coordinates remain the same?

A big thanks in advance,

Simon Chuptys


Aren Voorhees wrote:

Hey Simon,

The workflow below mostly sounds good. One thing to note however, is that you don't really want to make any changes to your geometry after you have already created a normal map. If you alter the geometry too much after the texture maps have been created, the maps won't look correct on the geometry anymore.

As far as retopologizing, it is not always necessary. It sort of depends on what sort of character you are working on. In some cases your starting low poly model can end up being your final geometry as well if you can plan it all out well enough at the beginning.

In other cases, the base geometry that you sculpt on might not be suitable for putting into a game, in which case you might model a whole new low poly geometry. In that case, you would probably generate your normal map as one of the last steps, by importing your high poly (from zbrush/mudbox) into Maya and creating the maps there.

Let me know if you have more questions!

Aren

That comes in handy: it looks like i shouldn't do the map extraction in mudbox. That explains!



Simon Chuptys wrote:

Hello there again!

Included image

First of all, i want to let you know that i appreciated your previous answer. It really cleared things up.

To get familiar with the whole process of modelling, sculpting and map extraction, i made some shinprotectors as a test. It all went good… until the map extraction. When i only extract a displacement map, a lot of details aren't present and the whole geometry looks blurry. Even after several extractions with different search distances and with minimal filtering or smoothing of the map (i followed the steps in this tutorial). After the displacement map, the normal map followed. This one on the other hand looked really good. But the problem with normal maps is, that when looked from aside, everything remains flat. The most satisfying result i get for the moment is to apply both a displacement and normal map. But is this a common way of working? And is it a problem that both maps represent the same geometry and thus (since the displacement map only does some 'raw' geometry) amplify parts of the geometry? (On the shinprotectors, this effect was minimal, but on other things, this might become a problem?) I've included some renders, to clarify what i mean. Maybe i just expect too much from a displacement map and will the 'blurry' effect be unnoticed once the shinprotecters are painted?

Another question is on the subject of sculpting. The characters armor consists of different parts (like the shinprotectors, chest, bracers, …). These parts are pretty thin, so when i try to sculpt near the edges, problems start to occur (i guess because mudbox has troubles to know on which side i want to sculpt). On the awesome wraith you created, there doesn't seem to occur any problems. Any tips on this?

Looking forward to an answer!

Simon


Aren Voorhees wrote:

Hey Simon,

Most game engines don't actually support displacement maps (at least not for characters anyway). So depending on what purposes you have planned for the character, you may only want to be rendering the normal maps. And yes, geometry tends to look flat when only using a normal map, but there are some ways around that. For example, in your low poly model (the one that would go into the game engine), you can add some additional edges on the areas you want to be less flat (on the shinguard thing, it would maybe be an additional bevel around the edge, and some extra edged on the detail around the knees). Then, once you apply the normal map, it can fake the dimension/shape of your high poly model pretty well. If you went this route, you would probably generate your normal map in 3dsMax or Maya, whichever one you're using. In Max, if you press the 0 key it brings up a window called “Render to Texture” which can be used to create normal maps and other types of maps. To use it, you just import your high poly model and the low poly one, then you can render out the maps (I can explain this in more detail, if you need).

As far as the sculpting on thin geo…hmm, I don't use Mudbox a lot for modeling, but I opened it up just for you :) I think the best way to avoid the problem you mentioned would be use the “Freeze brush” on the backside of the geometry that you don't want to affect. That should keep it in place while you work on the rest of it. Another way might be to do your sculpting on it's own layer, then use the erase brush on the part of the geo that you wanted to remain unaffected.

Hope that helps! Let me know if you have more…

Aren

Well, since The Wizards doesn't support displacement yet, i think normals maps and some basemodel tweaking will do for now.

Some topics for a next mail:

Pending...