Whether extruding, bridging, collapsing… pretty much anything, it’s as if ZModeler is “Q-Meshing” to collapse faces/edges at tiny thresholds, making it VERY difficult to keep accurate control of topology. Is there some global welding setting now, or something along those lines, that needs to be changed to prevent this?
Hi @Sixus1
I’m not sure what you’re describing here, but here are a few tips:
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Q-Mesh will not extrude if you hold down-shift–this allows you to freely move a target surface inward or outward along its normals.
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If you would like to extrude without Q-Mesh’s snapping/welding characteristics, use the Extrude or Transpose functions instead.
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Many Zmodeler tools have a “memory”, and will repeat the increment of the last move over and over again unless you make a significant change. This is useful when you want to apply the same change to multiple elements, multiple times by just lightly tapping them. If you want to make a more subtle move, you will have to make a more significant change to the element before commiting it–for instance by maybe moving the target by a much larger degree at first, then slowly sliding it back to the intended location.
If none of these tips apply to your situation, you will need to elaborate, and illustrate the issue with Zbrush screenshots if possible.
Below is a more detailed explanation with video attached:
Create a mesh with some edge loops as “hold loops” around tight spaces for hard surface modeling; then, select a poly or group of polys nearby and use Zmodeler’s extrude (or inset… or just about any other command). The edge loops nearby that are close together will collapse into one another in a manner similar to Qmesh actions while dragging for the extrude (or other) command. To prevent this collapsing, the extrusion has to be dragged past what seems like some kind of internally defined threshold, at which point the collapsing behavior reverts back to the original topology. If releasing from the command action at a very small degree, for instance in the case of making a very tight, small extrusion, then this collapsing occurs, ruining the topology.
This appears to me to be some kind of internal threshold set for automatically trying to weld vertices, however I haven’t found a setting yet that changes this. Currently, I’m using a few different workarounds so as to continue my work, but it is an incredibly aggravating problem that is impacting my productivity and speed greatly.
Attached is a video taken in Zbrush to give a good example of what I’ve described above. Thanks!
hmmm… would seem attaching video from dropbox didn’t work…
Hi @Sixus1
I watched your video. It’s difficult to make out what is going on, but I can’t reproduce your issue under normal circumstances. You’ll see I’ve modeled something similar to your topology:
If I had to guess, I’d guess you have a combination of problems going on. I was able to start reproducing similar weird behavior by scaling the tool abnormally small in the worldspace, AND by using a brush radius that was too large for the areas I was trying to target.
I would suggest performing a unify on your model to make sure it is in the “sweet spot” for working in Zbrush. Some reasons you’d want to do this are shown in this video. Meshes that are abnormally small or large in the Zbrush worldspace can perform oddly.
And then by way of general tip, reduce your Zmodeler Brush radius so you aren’t involving unwanted elements in your operation. I notice also that your polygroup target is set to “polygroup all”. Polygroup island would be a more accurate target for that situation–if you have other polygons you arent aware of assigned to the same polygroup, it can cause unexplained behavior.
Also be sure to attempt the operation with a mouse to rule out any potential issues with a pressure sensitive device.
I am having this same problem (zmodeler is randomly welding points when trying to extrude or even when stitching 2 points together it’ll randomly stitch other points around the model). As I work with DAZ3D models, they are the exact same size models I have been using for the last 6 years. I have had no issues with extruding, stitching, bridging etc, even the smallest of distances.
I didn’t have this issue in ZB2019 or any prior releases. It has only started happening in ZB2020. Nothing else in my workflow has changed, so this is definitely a bug that needs to addressed.
I even tried importing the “base model” at 1000% scale, but had the exact same issue. The size of the zmodeler brush had no impact.
The only way I have been able to make it stop happening is by unifying the subtools. However this is not going to work as the “base models” must be exported/imported in the exact same position to and from DAZ Studio and Zbrush in order to build clothing around the body. By unifying the subtools they are then exported offset and in the incorrect position to enable rigging.
Please help!
Update - This is now doing it even when the subtools have been unified
I’m having this problem in ZB2021 - attempting to extrude an edge or face polyloop, trying to Qmesh - details will disappear all over the mesh from vertices merging. I’ve tried unifying and T-posing using transpose master to achieve the optimal size, masking, mask by polygroups at 100 & topological on, changing draw preferences dynamic size to make the influence smaller (I’ve returned everything to normal settings since nothing has worked) and I have always used a mouse in Zbrush because a medical condition that precludes using a tablet.
Do I just scale it up to avoid this? It feels like WeldPoints is permanently on.
Bridge edges: 2 holes or just edges give the same result.
Say no more I have the exact same problem, for example when you use "inset " the inset snaps at some point, doesnt start right away, it is super annoying, especially when inseting multiple polygons at once it welds random points to each other, that is infuriating. 2020 had everything in order, Im working on 2020 until they fix that.
You may need to reduce the “ZModeler Welding Tolerance” to a minimal value in Preferences> Geometry. You’ll need to store the config in Preferences> Config> Store Config in order for the program to keep that change at startup.
Mind, if your mesh is abnormally small in the worldspace, this may also create issues.
Take care! 
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Hi, thank you so much, that fixed the issue for me, I was not aware there is a setting for that in preferences, seems like the default must have been lower in previous versions of Zbrush.