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About Decimation Master Performance

ZBrush Usage Questions ZBrush 2019.1 Usage Questions
#1

Hello Community.

I’ve been experiencing some problems with Zbrush 2019.1.2, specifically with Decimation Master. These are my PC Specs:

image

I’ve already tried changing the settings on the Preferences menu:

image

But no matter how many cores I set or if Turn on or Turn off -Uniform Mesh-, it still takes AGES to preprocess the meshes, I mean, ridiculously, like 20 minutes per subtool.

I wish there’s something else I could configure in order to fix this issue. Any help or advise you could give me is welcome and I’ll be really grateful about it.

All the best,
Pietro

#2

Hi Pietro.

Decimation master is performing more or less as expected for me here, so we need some more information.

  1. How many polygons do the “slow” subtools have? Decimation master can work with fairly dense meshes, but you will still run into a practical limit where it becomes too slow or fails altogether. Are the subtools in question of a polycount similar to what you’ve decimated in the past with no issues on your system?

  2. Does DM perform slowly on any subtool, regardless of polycount or topology, or only some specific subtools? As an experiment, does changing the topology, say with dynamesh, prior to decimating improve the performance? Certain types of topology can be more difficult for some of the processes in Zbrush to compute. For instance, ZRemesher tends to struggle more with overly “smashed” topology such as the type that can be generated by the Clip brush.

#3

Hello Spyndel,

This situation happens with anything above 1 Million polygons and only with Decimation Master. In my workflow, I always dynamesh my subtools before proceeding to decimation, so it doesn’t look as a complex mesh related problem.

Any other feature like ZRemesher works faster than it used to in my past PC which was far less powerful than my actual Workstation.

Decimation Master is the only Plug that seems to ignore the cores and only work with one (just me speculating); therefore, working even slower than in my past computer. The thing is I use this feature on every project, so, lots of time are being lost on my side.

#4

Well, on my end pre-processing a 1 .5 million poly sphere takes under a minute. Obviously this will vary with system, but if that is taking anywhere near 20 minutes like you said in your original post, something is wrong.

I would make one last check that it is a behavior that repeats itself across any mesh, and not just a specific series of subtools that might have an issue specific to them. If you’re confident DM is not performing as it should, there may be something wrong with your installation, or DM may not be functioning properly on your hardware configuration. In either event you may have to contact Support to have them help sort it out.

Good Luck!

#5

hi @piedro023

For reference:
My system runs on a 1950x, x399 pro carbon AC motherboard from MSI and 32 gigs of 3200MHz ram in quad channel.

Decimation Master Options: Number of threads 30 of 32. I’m guessing this is not a hard limit as I saw between 29 and 32 threads used, albeit at around 20-30%.
deci-dyna

Decimating a mesh of around 2.2 million points takes between 30 and 50 seconds depending on geometry:

  • simple smooth blob: 30s
  • same blob with some brush strokes and surface noise applied for more complex geometry: 50s
  • and dynameshed at around the same point count: 50s

I’d imagine pre-processing time will vary from mesh to mesh - the more details the longer the time.
It’s possible that there’s something wrong with the mesh. For example it happened to me a few times that a low res mesh, already decimated and to which I added some details using Sculptris Pro, didn’t want to pre-process at all. So I figure it’s something connected to some wonky geometry.
I never waited 20 minutes for it to finish though, neither did I check how many threads were being used at those particular problematic moments.

It’s the one thread being used that would worry me; I’d say reach out to support, maybe provide them the mesh in question, unless it doesn’t matter what mesh you try to pre-process.

cheers and good luck
Rafal

#6

Hello Rafal,

Yep, it happens with any subtool I preprocess, no matter it is a Torso, a gun or a simple sphere.

Thanks, I’ll investigate how to contact Support in order to get more intel on this.

All the best,
Pietro

#7

Hi Pietro,
no problem, you submit a ticket here:
https://support.pixologic.com/Tickets/Submit

Don’t hesitate to update this thread once you find the solution or the source of the problem.

I might be looking to upgrade to a newer threadripper and this kind of information is kind of crucial and not very common at the same time.

cheers
Rafal