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Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Fri 10. Nov 2017, 11:22
by dwindleflip
There is an odd bug with Zbrush 4R8 P2 and Wacom Intuos Pro Drivers where the intensity of the pressure sensitivity decreases significantly. You can test this by taking a dynamesh_sphere_128 project and sculpt on the sphere. Mask parts of the sphere. Notice how dark the mask is. Now continue to sculpt and after a short period of time, the pressure fedelity will drop, meaning your brush strokes and mask intensity will be significantly lower compared to when you first loaded up the project and tried to mask and sculpt.

I tried the latest drivers and the previous driver. This bug exists in both.

Note, this problem with Pressure sensitivity does not happen in photoshop. After extensive testing I could not find any pressure sensitivity issues in photoshop. Zbrush however will lose its range of sensitivity after a very short period of time sculpting.

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Fri 10. Nov 2017, 13:17
by wacom1
Does it work again when you restart ZBrush ? That would point to a problem in ZBrush (and should be reported to Pixologic).

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Fri 10. Nov 2017, 19:29
by dwindleflip
Here is a video of the bug. https://streamable.com/dolln

In this video you can see that if you repetitively draw a mask and undo, the bug will trigger. You will notice that the mask becomes lower in intensity and the brush size smaller, despite not having changed the brush size or intensity values of the brush.

Yes it works again when you restart Zbrush but only for a very short time. I've made a video that shows the issue. You can see exactly when the pressure range changes. The effect is as if you suddenly switched the wacom driver's pressure sensitivity slider to hard. A work around is to set the wacom driver to a softer setting for Zbrush, so that when Zbrush bugs out, the pressure curve is more normal (although its not quite normal).

I dont know if its wacom or Zbrush's bug but I do not remember having this issue with my intuos 3 large a few days ago. I have it with the intuos Pro 2017 large though.

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Sat 11. Nov 2017, 12:22
by dwindleflip
This is on a Windows 10 machine btw.

I just did a test to confirm that the intuos 3 does NOT have this issue with zbrush. It appears to be only related to my intuos Pro 2017 model and Zbrush.

I have a recorded video of the both tablets performing this test, and it has something to do with "undo" after drawing a stroke. At some point, when you undo, pressure sensitivity becomes "half" of the full range (for the lack of a better explanation). So brush size suddenly does not reach full size in relation to pen pressure, and intensity is also halved.

I think this is a driver bug not a zbrush bug because it happens only on the intuos pro and not the intuos 3. Please look into this to confirm these findings yourself because it makes my new Intuos Pro 2017 model virtually useless in Zbrush.

I've tried the latest intuos pro driver, the previous, and version 6.3.23-1. They all have this problem. Intuos 3 does not. I cant seem to cause a similar behavior in photoshop. So it does not seem like its a hardware issue.

It does not happen in Mudbox either.

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Sun 19. Nov 2017, 06:37
by dwindleflip
Any chance of you looking into this?

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Wed 13. Feb 2019, 14:55
by chrisf
I'm having the same bug with the latest version of ZBrush as well as with the Wacom Cintiq 16 (6.3.32-4)
I also had this before with my Intuos 3.
Win 10 Pro - German Language

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Thu 14. Feb 2019, 09:17
by wacom5
You probably need to install the latest version of Wintab:
  • Go to https://www.microsoft.com/en-us/downloa ... x?id=49497
  • Click on Download
  • From the list, select the correct Wintab driver for your system (64 or 32 bits; most used nowadays is 64)
  • Download and Install
  • Restart the computer
  • From the Wacom Tablet properties, make sure that Windows Ink is disabled.

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Thu 14. Feb 2019, 09:52
by chrisf
Thanks for the reply, wacom5.
Unfortunately this didn't help.

Is there a way to completely uninstall every setting and all data from wacom so that I can do a fresh reinstall?
Like remove everything from the registry and all Windows folders

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Fri 15. Feb 2019, 08:29
by chrisf
Alright .. I think I found the solution.

I switched from german to english Windows system language and since then the bug didn't appear again.

Hopefully this helps anyone with the same problem :)

Re: Zbrush 4R8 P2 Pressure Sensitivity Bug. It loses Pressure fidelity.

Posted: Fri 15. Feb 2019, 12:07
by wacom5
Interesting. I would not have thought of that. Thank you for sharing this with us.