Join Ryan Kittleson for an in-depth discussion in this video Setting up your model for retopology, part of Managing Edge Flow in ZBrush.
- Re-topology will completely remove details from a model and get rid of any sub-division levels, so there are a few preparations that you'll want to make before using ZRemesher. In this video, I'll show you how to set up to make sure that you don't lose any detail in your final model. So I've got a new session of ZBrush just started up here. And let's get a model to work with. I'm going to go into the Lightbox and go to Tool, and let's double click Demo Head.
Now we just need to click and drag in the canvas to bring this in here. And we need to go to Edit mode and we can turn off Lightbox. Now let's take a little closer look here at this head. It's got sub-division levels so if you hit shift d a few times, you can go down and see the various sub-division levels and if you hit d you can go up in the sub-division levels and see we've got some detail in the model. Let's look in the sub-tools as well. You can see there's two different sub-tools, we've got the head and we've got the eyes and teeth.
Now let's hit shift f, so we can see the wireframe of this model and I want to zoom in a little bit because we can tell a few things about this stock model that comes with ZBrush. It already has a sense of edge flow going, you know, it's got loops going around the eyes, loops around the mouth, but there's a few things about this that I don't really like and we're going to be cleaning these up. For one, there's a really nasty six pointed star right here at the junction of the nasal labial fold and the nostrils and that's just really bad for animation.
Another thing I want to clean up is the sternal coletal mastoid, this muscle right here that runs from the collarbone up to just behind the ear. And you can see that the muscle flows in this direction, but the topology is criss-crossing very awkwardly over it. And this is also bad for animation and bad for sculpting. Now whenever I re-topologize what I want to do is make a duplicate of the model that I'm re-topologizing so that I can always come back to the original if I need to. So let's go in our sub-tool palette and click Duplicate.
Now let's go ahead and click on this duplicate. Now this next step is optional, but just to make sure that we're really seeing what ZRemesher is doing, I want to really mess up this topology so that it loses all of its edge flow and I'm going to use Decimation Master to do that. Let's go into ZPlugin, let's go to Decimation Master, and let's pre-process the current model. That should just take a few seconds, and then now that it's pre-processed let's go back to Decimation Master, and we'll set the decimation percentage to, I don't know, something around 70, and Decimate Current.
Okay, so we've got the two models on top of each other, let's just hide the original, and let's also hide the eyes and mouth. Okay, so you can see now our topology is pretty much ruined, but that's just fine for what we want to do to it right now. We just want to see the difference between this sort of a mess of a topology and the new ZRemesher. Even though this step is optional, you might actually want to use it, in certain cases when your model that you want to ZRemesh has a lot of polygons, I'm talking like over 300,000 polygons.
ZRemesher likes to work on models that aren't super heavy so it can take a long time to process if you've got like a million polygons in your model, so if you have a lot, go ahead and decimate. Okay, now we're all set up for the next video. We've got a sub-tool of the original model as a back up and we have a second head where we've reduced the polygon count for more efficient re-topology.