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Blocky texture paint stroke interpolation
Closed, InvalidPublicTO DO


System Information
Custom build linux OS
Win 8.1 64 bit
GTX 980

Blender Version
Broken: ALL
Working: When this is fixed

Short description of error
on fast painting strokes, lines are blocky

Exact steps for others to reproduce the error

just paint fast strokes, either long or short, stroke will be blocky
Update rate just too slow, reminded me of old PC mouse back in the days

Event Timeline

WK Bong (lightbwk) raised the priority of this task from to 90.
WK Bong (lightbwk) updated the task description. (Show Details)
WK Bong (lightbwk) added a project: BF Blender.
WK Bong (lightbwk) edited a custom field.
Julian Eisel (Severin) changed the task status from Unknown Status to Invalid.Feb 5 2015, 3:24 PM
Julian Eisel (Severin) claimed this task.

Hey @WK Bong (lightbwk),
AFICS this is no bug, you can make this better by using the "Input Samples" value in the Stroke Panel.

So thanks for the report, but everything should work as expected :)

WK Bong (lightbwk) added a comment.EditedFeb 5 2015, 6:11 PM

It is still blocky even at high samples.
At sample of >10, the smoothing is causing too much lag for comfortable painting.
The line only smooth at 30 input samples with too much lag.

left to right, 10 samples (blocky), 20 samples (still blocky with noticeable lag), 30 samples (too lag, cannot paint)

Yeah, but I'm afraid we're touching the borders of our old OpenGL code there. Am I right @Antonis Ryakiotakis (psy-fi)?

It's actually an old issue that has to do with threading and small brush sizes:

If you use small brushes you might want to disable threading altogether by going to the performance panel and set threads to custom and 1.

See if that helps. I'll try to see if I can do something more for this issue.

Antonis Ryakiotakis (psy-fi) changed the task status from Invalid to Unknown Status.Feb 5 2015, 7:19 PM
Antonis Ryakiotakis (psy-fi) claimed this task.

Performance: 1 thread only
Input Samples at 10
Pressure is off

Thin strokes, can see the blocky part. Similar on larger brush.

Similar results when done with mouse, not graphic tablet problem.

Can you attach your test file here?

Blank file ready for painting.

I am not sure if this is a bug either. Very fast strokes usually means we don't sample the mouse very often. As far as I've seen Krita and Gimp also have the issue but they hide it with some line smoothing.

I'll wait for the file and if I can't see anything extremely laggy I'll close. Better interpolation is nice to have but I wouldn't count it as a bug but a feature request.

We also have the smooth stroke system but personally I don't find it very comfortable to work with.

Antonis Ryakiotakis (psy-fi) changed the task status from Unknown Status to Unknown Status.Feb 5 2015, 8:22 PM

Yep, can't see anything weird here, closing as TODO.

All the blocky grass part is caused by the same problem.

Smooth stroke cannot solve it. Start and end tapering by pen pressure are smooth out into dull ends.

Firealpaca has very nice way to taper line with smooth stroke.
Mypaint also has very nice tapering, without smoothing. Very natural. (deevad/artpen is a good one)
Krita has the same problem as Blender texpaint (smoothing off). With "weighted smoothing," it becomes a joy to use. With nice tapering as well.

note: Fast strokes are useful to get nice smooth arc, slow strokes will get jaggy lines.