Hello … I’m quite new to Zbrush and 3D overall I can do really basic stuff. I tried to use Zremesher in various setups to remesh certain model (low poly, maybe 8k polygons)
imported from game. I stumbled on various problems like 1) remeshed object doesn’t look good. 2) remesher tends to round all my edges while I want to have them sharp 3) I wanted to have loops in certain places (tried using Zmodeler brush to mark them but it helps just a little) 4) Overall quality mesh is … rather medium and bad at places where I will be needing it the most. I don’t quite understand how mesh is created, because there are places where there’s no details at all, and mesh is sooo dense, and on others its quite oposite. : frowning: The problems occurs expecially on the edges … (marked on blue)
Orange mesh its orginal mesh.
I’d like to ask you for some tips, how to address those problems.
Hello @Kap ,
When subdividing low poly geometry with subdivision smoothing active in ZBrush, edges need Creasing in order to stay sharp through the smoothing process. OR, the geometry needs to be drawn in such a way that points are denser in that area–two edges very close together effectively equals a crease when subdividing.
What you have in that screenshot is unsmoothed, low poly geometry. If you attempt to smooth it either through the subdivision process with smoothing enabled, or with Dynamic Subdivision as a virtual preview, those edges will soften in every area where the resolution isn’t dense enough to reinforce the detail, which is going to be most places on geometry that low in polycount. You don’t have any creasing defined.
In order to crease an edge, it needs to be accurately drawn right along the edge of the polygons you weant to crease. There is no one-button automatic retopology solution that can look at a complicated mesh shape like that, and draw the edges as accurately as a human can. In some cases, manual retopology will always be required. But ZRemesher can do a pretty good job if you give it some help.
This is however a skillset in itself, and not one I can cover in a single forum post. Basics:
- For simple, clean shapes with very cleanly defined edges, for instance mostly planar geometric forms, ZRemesher can probably do a pretty good job only with the “Detect Edges” setting enabled. If the mesh is particularly low poly, it can sometimes give ZRemesher more information to work with if you subdivide the mesh first.
- For more complicated shapes and mixtures of soft curves, or if your edges are not well defined–for instance as the result of a high poly sculpt where the user has been sculpting in imperfect edges by hand, ZRemesher will need more help. You can:
- Pre-crease your edges, and enable the “Keep Creases” option. ZRemesher will attempt to draw edges along those creases in the process, providing accurate edges that can be re-creased in the resulting mesh and then subdivided.
- My preferred option: create well-defined Polygroups for your mesh in which every line you want to be creased is separated on each side by a well drawn Polygroup. With the “Keep Groups” option enabled, ZRemesher will attempt to retain all those Polygroups, and draw the geometry accurately along the edges of those groups. Those groups can then all be creased at once after ZRemeshing with the Geometry> Crease> CreasePG option.
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The reason I prefer this is because well-defined Polygroups are very useful at every stage of ZBrush work, and survive scenarios that creases won’t.
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In some situations, it may be beneficial to combine “Keep Creasing” with “Keep Polygroups”. In other situations, the settings may conflict.
- ZRemesh at a high target polycount first to give ZRemesher ample points to work with to define the form, then once it has worked it out, reduce the polycount as far as you can before ZRemesher can no longer maintain the form with a series of “half” target polycounts.
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Along the way errors might creep in certain locations where the edge or topology is ill defined. This is usually the result of tiny, sometimes invisible splinter polygroups created at the edges of polygroups that may only be visible if you smooth the mesh. An edge can also break down if ZRemesher is trying to connect the topology in an awkward way.
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My advice in these situations is to simply correct minor errors as they pop up with ZModeler functions like Point> Stitch and the Polygroup functions, rather than trying to chase perfection with ZRemesher. You typically lose more time to trial and error than if you just do a bit of touch up as you go.
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ZRemesher is not going to be able to do much with extremely subtle surface detail like micro-insets or very thin extrusions. This sort of fine surface detail should be modeled in after the form and topology of the mesh is stable.
Good luck! 