Getting weird black lines on custom brush and Track Direction

[simon2]

Hi,

I'm trying to make a custom brush with a gradient and then use the paintbrush tool with the "Track Direction" dynamics to give the gradient to a line that I'm drawing. The brush works fine without dynamics, but when I apply the "Track Direction" dynamics, I get these weird artefacts. Per the image below:



I attach my brush, in case it's something I've done wrong making the brush.

[rich2005]

I do not think you have done anything wrong, look like it is associated with this post https://www.gimp-forum.net/Thread-Brush-problem--5967 and this bug https://gitlab.gnome.org/GNOME/gimp/-/issues/5509

What you can try is trim the brush into a circular shape so that edge rotation is negated. your trimmed brush attached. Use a small brush spacing, you still get boundary change edges but not the black pixels. Try working at a higher precision than 8bit - might help.

   

[simon2]

Thanks very much rich2005!

[simon2]

Still getting artefacts my end with your updated brush.

Is there something else I'm doing wrong?

[rich2005]

I honestly do not know. There is an issue with rotating a brush and generating those edge pixels. AFAIK not fixed.

This an animation of the default settings using that round brush, which has a transparent border.

https://i.imgur.com/AdszRVu.mp4

When you post a screenshot of a problem, always best to show the whole Gimp interface.

Maybe someone will come up with better advice.

[PixLab]

You are doing nothing wrong, it's just unusable, if you can report it over there https://gitlab.gnome.org/GNOME/gimp/-/issues > maybe, they will try to fix it.

30-second video > https://imgur.com/q0lnQ8e

The "only" thing I came across is to shrink the selection before Ctrl+C, but even though, it's far from perfect as you can see below

   

I also noticed changing the original/default size will worsen the black dirt