Working with very high poly meshes in max (8.0)

KevinCoyle

What is the best way to generate normal maps from very dense meshes? I know of many ways to do it, but there are problems with those approaches.

My current workflow is the following.

1) Model the low poly character
2) Model high detail model, focusing on main forms, hard details and other inorganic details.

3) Bring high detail model into zbrush. the high detail model is still fairly low poly, much higher than I'd want for a game character model but still a lower poly cage mesh, as I would do all the subdivision in zbrush.

4) subdivde the model and flesh out the forms and add organic details in zbrush and other finer details.

5) unwrap low poly game model

6) Bring high poly model into max.

This is where the problem arises. I can't use zbrush to create the normal maps because I need normal maps generated from comparing the low poly game model with the high poly model, not the base level mesh I brought into zbrush, which means I have to use max's render to texture to get my normal maps. The problem is the scene just becomes unworkable with such a high poly mesh. trying to tweak the projection cage is almost impossible because the viewport moves so slowly but I can't hide the high poly because I need it there to make sure it's not penetrating the projection cage at all.

I've read somewhere I think that Epic and maybe others broke models up into several parts to work on so the rest could be hidden to make the scene more managable while working. Wouldn't this cause seams to show up in the normal maps between the parts? And even if I could hide the parts I'm not working on to improve performace, I'm not sure my computer could handle the memory requirements of having the entire model loaded, even if only parts are being rendered. Would you bring each part in one at a time and make a normal map for each part, then composite them together in photoshop?

A little clarification on an efficient system for obtaining normal maps from very dense meshes would be greatly appreciated. Thanks

dnorth

Well, you can bake your normal maps in Zbrush. Zmapper allows you to create normal maps from arbitrary meshes. The interface is a little clunky but it works. Just check the Zmapper documentation.

Or, you could use xNormal, which works great:
xNormal. Again, let's you bake normals for arbitrary meshes.

If you definitely have to or want to use Max for some reason, I'm pretty useless since I use Maya. But I think poop has a tutorial where you make a new layer and then hide it before you import to make it workable?

KevinCoyle

The problem using Zmapper is it only works between subdivision levels of the same mesh. The mesh I bring into zbrush originally is not the same mesh I want to use ingame with the normal maps.

I haven't tried Normalx, I may look into that if It can do what I'm trying to do resonably fast

Thanks for the reply

Husch

Why don´t you model and unwrap your lowpoly model, optimize this model for subdivision, model your high poly model with keeping the UVs and import this model into Zbrush and finally use Zmapper?

Entity

xnormal is your solution, just make sure everything's aligned properly to avoid complications

dnorth

[ QUOTE ]
The problem using Zmapper is it only works between subdivision levels of the same mesh.

[/ QUOTE ]
Actually that's not true. If you look at the .pdf that comes with Zmapper, go to section 3 "Projecting Normal Maps Onto New Topology". You use the "projections" tab in Zmapper to "capture" the hi-res mesh, then close ZMapper, then open your game-res mesh, open Zmapper again, and bake the normal map. Again, pretty clunky but it works.

That being said, I've been much happier with results from xNormal.

thomasp

yep, zmapper does have no problem to use very different meshes for the baking process. however in my tests using the max-profile i could not figure out how to improve normalmap output. it seemed to have lots of problems picking up accurate fine detail on hard surface meshes. the same things baked just fine in max (and in the rather old open render bump tool as well).
a certain zbrush-competitor had similar problems to bake the normals correctly and just like zbrush did not provide obvious, useful controls to enhance the accuracy. i wonder how people deal with this.

J O T

Try the plugin Polycruncher. It can reduce your mesh by 90% and keep the outline/borders of your mesh. It will make a mess of the surface, but you should use it just so you can model around the high res mesh and make the scene managable.
Keeping the imported mesh as a editable mesh, not a editable poly, is also quicker in the viewport.
Yeah, compositing them in photoshop is the go, with the unwrap all laid out, its a simple case of deleting unwanted areas.

Palleschi

What I used to do for this is:
Slice your Zbrush HiRes mesh up and export chunks out.. Cast for each chunk.. Then assmeble in photshop. I still tend to do this because I use Kaldera in Max 6. I think it generates the best Normal Maps. Another Solution that most of us now use is XSI. I handles a lot of poly's no problem.

peace
-mike

PS havent tried xNormal but everyone seems to like it.. might give that as shot as others have posted

Joao Sapiro

i usually export chunkcs to 3ds max , lets say a har and some glasses ehe , i generate the maps separately, fix them up in photoshop , etc , and then join everything in photoshop , its really good because you can use everysingle texture space !