Reposting this from phabricator to get some feedback from artists. I posted it in russian vk group but didn't get much. Maybe I bother developers too much.

So, here is mockup:
http://i.imgur.com/MIc2BJv.jpg
http://i.imgur.com/tQc8qsC.jpg

Concept made from other Krita UI parts, just to show idea.
Logic similar to layers docker, I think it will make it more intuitive.
I don’t think preset icons will be useful (and easy to change) so I replaced it with brush engines icons (which is also discussable).

Points:
1. This is how mask looks like. Similar to layer group but with preset instead of folder itself. In this case, "texture brush" and "smudge texture" limited by "hard round" preset.
2. Preset control buttons. From left to right: copy preset (why not), move down, move up, add to mask (set preset above as mask), open preset settings (the whole settings – brush tips, curves, engine specific functions, etc.) and, on the right, delete preset from stack.
3. Fast access to most useful (in context of stacked brush) settings of the selected preset. Maybe sensors list is too problematic, but everything else would be very handy.
4. Some icons. First is "block iteration with canvas". It's for the case if you want smudge brush blend only the stroke itself. Or don't want multiply brush to darken your panting. Or erase brush to erase canvas and etc.
Second icon is inherit alpha, works analogically to layer inherit alpha - don't let the brush to paint outside of all brushes below.
And last icon. It's my crazy idea to set color for each preset in the stack. Let artist choose between foreground color (normal mode), background color, or choose "static" color, independent of current color. In the example "rake" brush in static mode and it always will be light pink color. Useful with different color modes.

This is concept. It's made to cover all possibilities and even more but I doubt it's good idea to implement all in once. Probably it's easier to add this only for pixel brush engine and maybe add support for other engines and some other functions later.

I also have idea for one or two brush settings that would be super useful in context of stacked brushes (and just useful with regular brushes). Not sure where I should describe it. Create another topic or do it here?

Hm... That would make stacked brushes a bit like texture -- which is probably not the easiest thing. Currently, the implementation is done as a separate brush engine where you can stack presets on top of each other. That works...

The alternative would be a separate tip tab in the brush tips, where you can stack predefined brush tips. Though that makes it harder to use the auto brush tips in a brush stack. This isn't something that already has been coded.

boudewijn wrote:Hm... That would make stacked brushes a bit like texture -- which is probably not the easiest thing. Currently, the implementation is done as a separate brush engine where you can stack presets on top of each other. That works...

Yes, it's sort of alternative (or addition) to texture. Imo, stacked brushes will be better than texture in most cases even with only a small part of this will be done.
As I understand phabricator discussion it'll be another brush engine but looks like brush option for user.

boudewijn wrote:The alternative would be a separate tip tab in the brush tips, where you can stack predefined brush tips. Though that makes it harder to use the auto brush tips in a brush stack. This isn't something that already has been coded.

This is very similar to PS double brushes (PS doesn't have auto generated tips). It still would be very useful but less flexible. I'd like to use most brush settings and curves for some of them which is not possible(?) with that system. Also PS have a dozen blending modes for double brushes and textures that krita doesn't have. So, this alternative will be more limited.

I think stacked brush mostly will be used with two\three pixel brushes with mask mode, so implementing like this concept only for pixel brush should cover about 80% of user cases. Though I'd like to have pixel\smudge brush hybrid but rather because I cannot disable blending without problems (it's reported on bugtracker as complicated issue).

Which photoshop blending modes doesn't Krita have? I thought we had all of them covered...

Note that I mean blending modes for textures or dual brush. Krita have only Multiply and Substract, my PS CC 2015 also have Darken, Overlay, Color dodge, Color burn, Linear burn, Hard mix and Linear height. Some of them looks very similar though.

Hi There,

After looking through the threads to see if there was anything similar to what I was going to post. I found this one so seemed ok to post this here as an addition to the original. I can move it to a separate post if needed.

I too have a similar idea for another head on a brush to create more realistic brushes. Here is the post I was going to create, sorry I didn't have time to mock anything up but I tried to explain it.

Puropse:
Have the ability to have a main head to a brush and a secondary one if desired that is editable also.

Reason:
Curently I use 2 different brushes to achieve more detailed/realistic brush types i.e spray paint, thick paint, splats etc. If we had this as an option some more realistic/experimental brushes could be achieved in one brush.

Example:
For example if we had a brush set up as a spray, as in we set up a brush to generate a lot of random dots that scatter as desired to simulate a 'spray' of dots. Then as the second brush head select a basic airbrush with it that would do the fade effect. Together they would be more like a spraycan paint effect.

Options:
- To be able to turn on and off a secondary brush head option to any brush if desired. Possibly a checkbox.
- To be able to toggle the settings for the secondary brush head so it shares the same settings as the main brush head. Possibly a checkbox.
- To be able to alter the settings for each brush head independantly

Ideas for toggle and independant settings:
If a user wanted to use the same settings for both brushes but only wanted to tweak a couple of those settings for the secondary brush head. Then have an option to 'use main settings' but so they do not toggle with the main brush head settings.
So there could be a:-
- 'toggle settings' one change on any of the brush heads does the same on both brush heads)
or
- 'use settings' which when selected uses the main Brush head settings but they are independatly editable per brush head.