Hello,

I spend a few hours searching for a solution without success, maybe someone of you recognize this problem:
Large brush strokes requires a lot of time to render. On a 4k image a few strokes can take up to 5+ minutes to complete (I can still paint during this time). But the CPU usage is about 15-30% on a 6-core processor (AMD FX 6300). I'm using Krita 4.0.3, the problem happens since 3.0.0, the multithreading updates made no difference. I tried using the new brushes too, no difference.

8 GB RAM
GPU: GT 640

In the Performance tab I checked if all 6 cores are selected (they are), disabled vector optimization and switched between direct3D and openGL without any results.
The performance logging did not output a file. If it is important I will try again.

Thanks in advance!

What kind of canvas are you running these operations on? (Pixel size, bit depth, color model, and maybe the kind of layers you're typically using)

TheraHedwig wrote:What kind of canvas are you running these operations on? (Pixel size, bit depth, color model, and maybe the kind of layers you're typically using)

Usually on the A3 300ppi template (3508*4960), or 4k in 16:9 format with 16-bit float channel, default profile (sRGB-elle-V2-g10), but the performance keeps the same on a 1000px 8bit canvas if the affected area is the same (brush size).
Layers reach from 1 to over 20, it is not affecting the performance. I think that drawing on the non alpha background layer is a little but faster. The layers properties are the same as the document.

Only brushes which transforms existing pixels like the wet brush appears to be slow.

Thanks for the fast reply!

The wet brush, or rather, the color smudge brush in general is indeed the slowest brush engine in Krita. This is because it draws a dab twice: once for the smearing and once for the color. It is also not multithreaded. There's not much you can do to speed it up. Some options:

1. f5->brush tip->lower the precision.
2. f5->brush tip->increase the spacing.
3. Don't use the color smudge brush for big canvases, instead use the pixel brush, which is multithreaded, and use a glossing workflow to mix colors. You can then switch to the color smudge brush when polishing, where it will be useful to even out gradients from the glossing.

TheraHedwig wrote:The wet brush, or rather, the color smudge brush in general is indeed the slowest brush engine in Krita. This is because it draws a dab twice: once for the smearing and once for the color. It is also not multithreaded. There's not much you can do to speed it up.

1. f5->brush tip->lower the precision.
2. f5->brush tip->increase the spacing.
3. Don't use the color smudge brush for big canvases, instead use the pixel brush, which is multithreaded, and use a glossing workflow to mix colors. You can then switch to the color smudge brush when polishing, where it will be useful to even out gradients from the glossing.

Oh, I did not know that this one isn't threaded. I found spacing, but precision can not be changed. How can I edit the value?
Thank you for the link!