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UV Master Unwrap is stuck on "cutting handle" - unable to proceed.

ZBrush Usage Questions
#1

Hi,

I’ve tried texturing several of my complex mandelbulb-derived objects using polypaint. I am now trying to unwrap them so that I can generate a UV map for export.
I’ve tried a few models so far, and when I run UV Master’s unwrap operation, the message at the top says “Unwrapping: polygroup x/x, cutting handle x/x …” in the top. It hangs for several minutes without changing, and then I get a crash message.

Another unusual thing about the progress message is that it reports a much larger number of polygroups than I actually have. Such as “unwrapping: polygroup 1/41” when I clearly don’t have that many polygroups (1-5 depending on attempt).

Stuff I’ve tried:
-I’ve run “mesh integrity” under the Geometry menu. It reported that it fixed all the errors in the mesh. I even did this BEFORE I painted on the texture.
-I’ve cut the mesh into multiple subtools before running UV master, just basic slices. It made no difference as far as I could tell.
-I’ve worked on a clone.

Basic system info:
-i7 CPU - 3.33 GHz
-24 GB RAM
-64-bit OS
-Windows 7

I’ve attached a screenshot of one of my models (a clone) with the progress message on the top left.

Newbie here - hopefully not something obvious. :\ Many thanks in advance for any help.

Edit: This model, as well as the others I’ve tried, has “holes” and “loops.” Could that be causing the issue? Here’s a sliced version with “double” turned on under Display Properties so you can see what I mean.

Attachments

2014-09-07_121955.jpg

2014-09-07_115411.jpg

#2

Sounds like there might be an error with the polygroups. Try clearing them out by putting everything into a single polygroup. You can then try creating brand new polygroups if you use the polygroup option in UV Master, or just try unwrapping as-is.

#3

Hi, thanks for the reply.

I just tried it – went into “group visible” under the polygroups menu, then selected the “polygroups” option in UV master.

Unfortunately, it’s still stuck on “cutting handle” though now it’s saying: “Unwrapping: polygroup 1/150, cutting handle 1/28 …” whereas before it was “Unwrapping: polygroup 1/41, cutting handle 1/30.”
(So somehow unifying the polygroups actually gave me more “polygroups” and less “handles” to cut? :confused:)

Currently I’m trying something new - which is to select “wait” instead of “close the program” when the “Zbrush has stopped responding” message pops up. Perhaps it just needs to take a long time to crunch or something. After all, Zbrush.exe is still taking up some of my CPU and RAM. But I’m guessing it wouldn’t work since “zbrush.exe” is labeled as “Not Responding” within my resource monitor.

Edit: simply waiting does not seem to work.

#4

Try decimating or Zremesh your model and run the UV process on the lower poly version. It might be too many polys for UV unwrapping to process and thus taking long and locking up. Don’t forget to save a copy of your model first in case you lose detail.

#5

Finally got it to work! I initially tried both approaches to reducing the mesh.

–When I use the Decimation Master plugin (at 20%) to reduce the model and then use UV master’s unwrap, I get the same “cutting handle” message in the progress bar. Only now there are many MORE handles. Probably not the way to go…

–When I use Zremesher to reduce the polycount and then run UV master’s unwrap, I get a pop-up error message this time, saying “An error occured during the process!” However, clicking “dynamesh” seemed to do the trick! I was able to save out my UV!

I still had to do a lot of trial and error with it, so to anyone weird voxel-derived meshes… try this:

  1. Fix mesh errors under Geometry > MeshIntegrity
  2. Close holes under Geometry > Modify Topology
  3. Make sure it’s only ONE polygroup - make sure this is done AFTER you close holes. Polygroups > GroupVisible
  4. Enable dynamesh.
  5. Run Zremesher, NOT Decimation master, to reduce the size of your mesh.
  6. UV master’s unwrap should now work. It might still take a couple minutes.

Thanks for the help.

#6

At a guess I would say there was a problem with your mesh that Dynameshing fixed. Well done on fixing it.

#7

The same thing happened to me, and I found a solution.

After cleaning the mesh, being a “complex” model, you must divide it into at least 2 polygroups.

Try it and you will see that it will let you do the unwrap without any problem

#8

I wish it would be possible to stop the process of unwrapping UVs via Esc (like with other ZBrush tools)