ZBrushCentral

Transpose master exploding subtools

ZBrush Usage Questions
#1

Hi! I am trying to pose a rather complex tool (129 subtools, 169 million points) using transpose master and am running into the “exploding subtool” problem, ie. the resulting T-Pose has several meshes that explode into spikey masses of triangles, or “perforated” meshes that have spikes shooting off of them to other subtools. Alternately, zBrush simply crashes while reading the GoZ file. I have tried several remedies, including splitting the subtools that have been mirrored into left and right subtools as well as cloning the subtools into another file, but the problem still persists.

I’ve tried isolating which subtools might be the problem by doing transpose master with each subtool in isolation, each subtool pair (L & R) in isolation, gradually adding subtools, etc… and no individual subtool or subtool pair explodes in isolation, or even with a few other subtools turned on. Only at some random critical mass of subtools on do they start to interact and points start jetting between them creating the dreaded spikes. I’ve seen no consistency in terms of a point count or subtool count as to when that happens.

I have several subtools that are Umeshes, and I suspect they are the cause, though as mentioned above they do not explode in isolation or even in combination with a few other subtools, and I have been able to turn on quite a few subtools including a couple of Umeshes without anything exploding. I have also tried turning off all Umeshes and running Transpose Master, but zBrush just crashes. But with ALL subtools on, I get a “trouble loading one file” error message and it gives me the 6-pointed star instead.

Here’s how weird it gets: Turning on one particular group of subtools (including some Umeshes) works just fine. I experimented by turning on one additional subtool (A Umesh from another Subtool folder) and now a bunch of subtools that were previously fine (but mirrored) are spiking between them. Ironically though, the new subtool is NOT exploding. But then once I split the mirrored subtools into left and right subtools, zBrush crashes when running Transpose Master.

Anyway, I’m at a loss as to how to isolate the problem. I’m guessing that there is some vertex ID confusion happening between subtools, as high-poly subtools don’t just explode into a mass of triangles, but are pock-marked with points that shoot off to connect to other subtools. Is there any “clean up mesh” operation I can do that might help? Is this a problem you’ve seen before with Umeshes? Could it have anything to do with the use of folders? Any new avenues to pursue would be helpful.

Thanks,
Phil.

Zbrush 2021.6.2
Mac OSX Mojave
2017 iMac Pro

#2

Hi @PhilSaunders

There are a number of possibilities here, but it sounds as if your meshes may just be too high in resolution. Transpose Master gives the best results for multi-resolution meshes with a low poly base. The low poly base is posed, the changes are sent back to the multi-res mesh at the base level, and the higher subdivision levels are updated with the change.

Lower poly meshes will perform much better when being posed, will be less prone to surface distortion, and easier to fix in the event that distortion occurs. Additionally, there is just much more opportunity for meshes to sort of freak out in unanticipated ways the more points the surface has.

Other possibilities include:

  1. Something about your process is changing the topology or point order during the posing operations. The point order must remain unchanged. Please see the Transpose Master documentation for notes on functions that may change the point order:

http://docs.pixologic.com/user-guide/zbrush-plugins/transpose-master/

  1. One or more of the subtools involved has problematic geometry. Be sure to check each subtool with Tool> Geometry> Mesh Integrity> Check Mesh for issues.

  2. Problematic UVs. If UVs are present, try deleting these before sending to TM.

If you can’t sort it out and nothing that I mentioned above helps you figure out the problem, head on over to Pixologic Support and Start a Conversation. We’d be happy to examine your issue further.

:slight_smile:

#3

Thanks for the reply Spyndel,

Yeah, I was afraid that it simply might be the point count. I’ve been using Transpose Master for years without issues, this is the first time I’ve encountered anything, also the first time I’ve used Umeshes, which is why I suspected them as the problem. Normally when I boolean I’ve used dynamesh booleans, but I was enjoying maintaining lightweight clean polyflow with Live Booleans.

The majority of my subtools are traditional multi-subdivision-level meshes, particularly the underlying ones that will be “bending” at the joints. The high-poly ones are hard-surface armor plates that started out as really low poly surfaces made with the topology brush and zmodeler with dynamic subdivisions and live booleans, but that I ultimately “flattened” into Umeshes for the purpose of both posing and exporting to Keyshot. I’d love to have kept them lower poly, but posing with live booleans is impractical and Keyshot won’t recognize them anyway. And the duplicating/zremeshing at low poly/reprojecting pipeline won’t preserve my clean polygroups for material breakups in Keyshot. Not to mention losing the crisp edges and detail of the booleans.

I’d like to boolean at a lower subdivision level and keep lightweight surfaces, but the triangles created by the Umesh operation preclude clean subdivision and the results don’t turn out great.

So I tried out Mesh Integrity on the previous selection of subtools, and sure enough, a couple of the subtools (one Umesh and one that I had cut up with Curve Slice) had edges shared by more than two polys. Unfortunately once they were fixed, Transpose Master exploded ALL OF THE OTHER SUBTOOLS that were working before! The two “fixed” subtools naturally were totally clean. Go figure. So back to square one.

As to your other suggestions:

  1. I don’t even get to the posing part. T-Pose mesh is already exploded.
  2. No UVs

Not sure what the point limit per subtool is for transpose master, but the subtools I’m cloning into another tool to test add up to about 50 million polys and the heaviest one is about 16 million polys. I’ve seen so many super detailed hard surface models I never imagined mine would be pushing the limits.

My next option I guess is to dynamesh the heavier subtools but I hate to lose the clean poly flow. If that doesn’t work I’ll head over to Pixologic support per your suggestion.

Thanks again,

Phil.