ZBrushCentral

Retopology and topology tools

ZBrush Usage Questions
#1

I was talking to some people the other day who basically were trying to tell me that you still needed a polygon modeler, especially for games, to work in zbrush. Some of them use zbrush and I was wondering how they came to their conclusions. So I decided that I would post here and try to give some love to zbrush’s polygonal modeling tools, that seem to be looked over, even feared or hated by many artists.

I know that you can box model from the ground up in zbrush but that doesn’t really take advantage of the programs strengths I think. But the topology tools offer a really cool way to combine the two experiences of digital sculpting and poly manipulation. Being one of those people who really grew up modeling with polys and subdivisional meshes—although I never want to go back after sculpting in zbrush—I still love to work with them and like to keep them a part of the workflow.

So I thought that I would try to get an idea about how other people are using these tools by starting with a workflow question. I was wondering if it would be worth retopologizing your model as you sculpt it? For instance; after you do the zspheres, adaptive skin, convert your mesh and block out the shapes to about 2-3 million polys. Can there be any advantages to retopologizing before you finish or would you just always want to save that for the last step?

#2

i like to spend a very small amount of time sculpting the zsphere, and retopologizing pretty early on. spending lots of time sculpting a box mesh like zspheres is limiting and makes it harder for me. zspheres is still probably my favorite way to start a mesh, or box modeling with symmetry in lightwave

#3

This issues go deeper than simple topology manipulation. Zspheres and ZB’s retopo tools are a good, basic approach, but they lack sophistication of more mature polygon modelers, such as Modo or Silo. For example, simply splitting loops of polygons is a much bigger chore in ZB with re-topo tools than a much simpler option in other modelers. Moreover, ZB’s re-topo tools depend on adaptive-skin generation; this makes low-poly models with branches, such as a hand problematic. For example, ZB’s adaptive sklin algolrithm can get confused on branches with only four sides (a common cage topology for a finger, for example.)

The next reason that for games work you need a seperate modeller is that ZB’s UV management and editing is considerably limited compared to a polygon-modeller. UVs are critical to efficient, editable maps. (A PUV or GUV map is sadly uneditable in an artisitc way with an image manipulatiuon progam like Photoshop.)

Don’t get me wrong, for my personal work, I usually start with a Zsphere model, quickly tossed together. I will often use ZB’s retopo tools to adjust geometry density along the way. However, when it comes time to use the model for games or animation, I inevitably need to construct an animatable base mesh, with an efficient UV structure before taking the model out of ZB as displacement, texture and normal maps.

Fortunately, ZB makes this relative easy with its reprojection tools. A little reprojection, a little tweaking, and an efficient animatable mesh with maps can be then be exported for next stage of development.

In my work, I retopo in ZB when I need to. In general this will often become apparent to me around level 4 or 5 as I have a pretty detailed block-out.

-K

#4

Besides topogun. Is there any software that allows me to import a high res sculpt from ZBrush and retopo inside of that application? So I can utilize better retopo tools?

I use Maya, but I’ve never tried to retopo a high resolution zbrush mesh. I have a feeling the viewport would spaz out with such a high polycount.

#5

there is a retopo plugin for maya, but as far as i know it was only for maya 8.5 it was called nex. it worked pretty good. if you get version 1.5 i guess its for maya 7 or newer

#6

Some people may not feel comfortable use zbrush’s retopology tools so they have the option of exporting the mesh and retopologising it in their native 3d program. You can either reduce the subdivision to a sane poly count and export or you can export the hi-res mesh in chunks so it becomes easier to retopologise. People have their own ways of doing things but it can be done at any level you feel comfortable with.

Cheers,
Revanto :stuck_out_tongue:

#7

also after learning the retopo tools in zbrush i’ve loved it. i’ve used zbrush to retop a bunch of my models. i like the option of polypainting the new topology on a model and then retopping it. it’s helped me become tons better at just having better topology as i model in maya

#8

I know its a competitor, but 3d coat -www.3dcoat.com has very nice retopology tools, compared to actual ZB 3.1 ones. maybe ZB 4.0 will add more options. it does UVs also, but dunno about quality of the toolset for them - could be bit basic for now.

about workflow, however, you can retopo when you want, but i think the best is to do it when you have all the basic features of your character quite nailed. since you reproject sculpting onto a new - good topology, you’ll take advantage from this when you’ll sculpt finer details, because you’ll have the right pilys in the right place yet.