zBrush: High Poly to Low Poly Techniques

Devon M

Just as the title states. I'm fairly new to zBrush, and I'm trying to find a good workflow for taking my high poly mesh and breaking it down to a low poly mesh (as a video game model).

I was using Decimation inside zBrush, but I had a friend tell me that was "archaic" and that there are better, more optimized ways of getting a low poly mesh. He suggested zRemesher. I tried it out, but it doesn't retain the details of my mesh too well (my high poly mesh has lots of curves and sharp divots. It's a rock formation) I tried decimation again, and it retains details pretty well, but the mesh looks very messy.

Any suggestions from you seasoned veterans? Like I said, I'm fairly new to zBrush, and I'm trying to find a good, solid workflow for getting a low poly mesh from a high poly mesh. Thank you all who leave advice and tips!

pior

I'm fairly new to zBrush, and I'm trying to find a good workflow for taking my high poly mesh and breaking it down to a low poly mesh (as a video game model).

Then first and foremost you need to know the ins and outs of building solid topology by hand (either in a regular 3d program like Maya/Max, or a dedicated retopo environment like Topogun) before attempting any seemingly time saving shortcut.

Now I am not saying that zremesher and decimation master don't have their uses for lowpoly asset creation (heck, I just used them on parts of a deformable game character just now and they did the job for the particular need I had) but there is no way around it, you'll have to know how to build tightly controlled geometry first. 

I understand that this might not really answer your question, but I thought I'd mention it anyways since the way you phrased it somehow suggested that building things by hand wasn't an option, while it certainly always is

musashidan

I'm with @pior on this. All too often artists new to the 3D pipeline post things like: 'UV unwrapping is so boring, is there a button I can press that will do it for me?' or 'My sculpt look terrible, how can I make it look better?' or 'Why do the out-of-the-box Substances not make my asset look AAA' 

An understanding of the fundamentals, and the WHY we do things, as well as hard work and practice, is so important. It seems like all those on the 3D learning path just don't have the patience to want to put in the work on the less glamorous aspects of asset creation. Now I'm not pointing the finger specifically at you, OP, as you have been advised by a friend and are following up on the advice here. But the question of auto-topo is a good one to ponder. Whilst it certainly has its uses, no doubt, understanding the process by way of manual re-topo is crucial: it affects UVing and animation(if applicable). Understanding how triangulation affects the surface normals, knowing what verts to remove or edges to turn without disrupting the silhouette, etc. All these fundamentals can be experienced by doing the work. The rock example is perfect in that it is probably the most forgiving asset you'll have to retop. Decimation master does work well for rocks, but if your next asset is a multi-part, animated machine-gun for an AAA FPS.........then you're in trouble.

Taking the easy way out every time will eventually catch you out. Having a wide base of knowledge and the practical experience to tackle any potential job will not.

Devon M

Sorry for the late replies, but thank you so much @musashidan and @pior

Guess it's time to get my hands dirty on my next project. My latest workflow has been to create a base geometry in Maya, bring it to zBrush to get the high poly, and then bring that down to a nice low poly within zBrush. 

So, you both suggest I do the low poly by hand to understand the core fundamentals, which is very sound advice. Whereas I'm sort of new to zBrush, I'm well experienced in Maya (I'd say between intermediate and expert level.) Would a suggested workflow be something like bringing the high poly into Maya and quad draw a low poly? 

PS. Didn't mean to make it sound like making the low poly manually wasn't an option. I was simply looking for solid workflows for going HP to LP to get a good understanding where to start (and what to avoid, like the "auto" topology stuff.)

Once again, thank you both so much for the advice!

Sean_P

Hey Devon,

What kind of things are you modelling? If I knew I might be able to help.  For instance if your modelling a bust and your base mesh has good topology then keep your subdivision levels in zbrush and export sub division level 1 or 2 then bake the high poly and that might work for you. But If your using dynamesh that changes everything.

Sean_P

I apologize, just re-read your post and it looks like your modelling a rock formation, decimation master with cleanup in maya (merge verts etc) might do the trick or decimate so it retains detail and doesn't slow maya and use quad draw.

Devon M

@Sean_P Hey man, thank you so much for the advice. I've been real busy, so sorry for the late response. 

Devon M

But yea, I don't normally do character models. In fact, I'm an environment artist. I do prefer the more natural environments (trees, rocks, vegetation, etc.)