GPencil – Unwanted Dots In Strokes #80906

System Information
Operating system: Linux-5.4.0-47-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 1660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.100

Blender Version
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-09-17 12:10, hash: 82bd1287dd
Worked: (newest version of Blender that worked as expected)

Short description of error
When rendering thick lines the lines will have some unwanted transparent dots. Especially if you turn the percentage of the render resolution up to 200%. Take a look at the attached images (in full size) wehre I marked the dots with red circles:

100% of the standard render resolution (less unwanted dots)

200% of the standard render resolution (more unwanted dots)

This issue might occur on NVIDIA graphics cards only (see comment from @JSM).

Exact steps for others to reproduce the error
GPencil_Unwanted_Dots_r0.blend

Render the attached .blend file, or:

Open Blender and select 2D Animation on the Splash Screen
Draw some thick lines
Turn the percentage of the standard render resolution up to 200%
Render the image and inspect the lines

––––––––––––––––––––--

Have fun in the sun! 😁

Added subscriber: @ronsn

Added subscriber: @JSM

Can confirm; I have this issue as well.
Tested Blender versions all the way back to 2.80 and the issue persists.

System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 452.06

Blender Versions tested
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-09-16 21:05, hash: 27660b3cd9
Broken: version: 2.90.0, branch: master, commit date: 2020-08-31 11:26, hash: 0330d1af29
Broken: version: 2.83.6, branch: master, commit date: 2020-09-09 07:32, hash: 8610c69777
Broken: version: 2.80 (sub 75), branch: master, commit date: 2019-07-29 14:47, hash: f6cb5f5449

Added subscriber: @mano-wii

Changed status from 'Needs Triage' to: 'Needs User Info'

Here is my resulting file.

Am I looking at the wrong place? Because I'm not finding any dot.

Please try the latest daily build: https://builder.blender.org/download/

Go to File → Defaults → Load Factory Settings and then load your file to see if you still can reproduce this issue.

Operating system: Windows-10-10.0.18941 64 Bits
Graphics card: Radeon (TM) RX 480 Graphics ATI Technologies Inc. 4.5.13596 Core Profile Context 20.10.19.02 27.20.1019.2002

@mano-wii When I wrote this issue I already used the latest version from buildbot. But okay, I tested again with the latest available version and the issue still exists. This time I made a screen capture where you can see, that the dots are like quantum fluctuation. They appear and disappear 😅

This was done with Factory Settings but I increased the contrast afterwards:
gpencil_unwanted_dots_r0.mp4

Maybe it's an issue with NVIDIA cards 🤷‍♂️

–––––––––––––––––

System Information
Operating system: Linux-5.4.0-47-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 1660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 440.100

Blender Version
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-09-20 18:23, hash: e14894aad2

Changed status from 'Needs User Info' to: 'Needs Triage'

So is the step 4 (render the image and inspect the lines) optional?
I still can't reproduce the problem :\

@mano-wii: Yes step 4 seems to be optional. I discovered the fluctuation just today. But if I render the image again and again the dots stay at the same spot. I can't see any dot in your rendered image.
@JSM has a NVIDIA card as well but newer driver than me and he has the same issue. So maybe it's an NVIDIA related issue and some Blender developer with an NVIDIA card can reproduce this behavior.

This definitely might be a bug specific to nvidia gpus.
tested with latest buildbot build on my other system (which has an amd gpu):
System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: Radeon RX 580 Series ATI Technologies Inc. 4.5.13559 Core Profile Context 26.20.12028.2
No issues/dots

⠀
But on my my system with a nvidia gpu the issue persists
System Information
Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.38
has dots:

Blender Version
version: 2.91.0 Alpha, branch: master, commit date: 2020-09-20 18:23, hash: e14894aad2

Also my old: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 442.19 has issues as well.

Added subscribers: @lichtwerk, @iss

No issue here either - AMD card. @lichtwerk can you check?

Changed status from 'Needs Triage' to: 'Confirmed'

Can confirm

**System Information**
Operating system: Linux-5.8.4-200.fc32.x86_64-x86_64-with-fedora-32-Thirty_Two 64 Bits
Graphics card: GeForce GTX 970M/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 450.66
version: 2.91.0 Alpha, branch: master, commit date: 2020-09-28 10:06, hash: `rBf7655dd322dd`

Added subscriber: @antoniov

I have tested on Windows with NVIDIA RTX2080TI and sometimes get dots. I have used 2D template a draw a simple stroke.

Can you reproduce the bug with the latest versions? I have not had these points for weeks.

Using the file from the report, I still see the dots

Issues are still here too (also with new drawings):

System Information
Operating system: Linux-5.4.0-52-generic-x86_64-with-debian-bullseye-sid 64 Bits
Graphics card: GeForce GTX 1660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 450.80.02

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-11-11 22:08, hash: 2ef2b3e0fd

Still have issues as well
(with supplied file and new drawings)

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30

Blender Version
Broken: version: 2.92.0 Alpha, branch: master, commit date: 2020-11-11 22:08, hash: 2ef2b3e0fd

So I found a way to make the dots even more severe and the underlying case perhaps.

If you take any stroke, even a smaller radius like 25 px, subdivide it; the dots show up and get worse.
This makes me think it has to do with the draw code(?) and spacing between Grease pencil vertexes.
see attached video.

Desktop 2022.04.15 - 04.28.45.02.mp4

Heavily subdivided stroke example image:

So the work around until this gets fixed is simplify modifier or simplify operator on affected strokes.

Tested on
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 2070 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 512.15

Blender Version
3.1.2, branch: master, commit date: 2022-03-31 17:40, hash: cc66d1020c
3.2.0 Alpha, branch: master, commit date: 2022-04-14 19:51, hash: 48ff456a4b

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

GPencil – Unwanted Dots In Strokes #80906