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Pressure Sensitivity Opacity Brush Connections

Posted: 31 Oct 2024, 15:23
by kelanhordos
I realize this is a very old thread, but I cannot find more recent discussion about this issue, and with the release of v12, I am wondering if there is hope for this issue to be addressed?
(If it would be better to continue the thread in the original topic, please let me know and I can repost this there, I'm not sure about resurrecting a 9 year old thread.)

https://forum.tvpaint.com/viewtopic.php ... ow+opacity

When I first started using TVpaint, looking into remaking PS brushes and understanding the similarities, I read things on the forum to understand better and came across this kind of information and just took it at face value that opacity in TVpaint is actually Flow in other software, which I've always found less useful to have a pressure control on personally. In that thread above you can find the following quote from Elodie talking about the issue
In other software, Opacity is named "Flow" and Power is named "Opacity".

So as primarily an animator and not needed to paint a ton I moved on and got used to Tvpaint's brush system, which for drawing IS fantastic, so I never really thought of it until more recently. In the last year and a bit I needed to use painting more, and having gotten so used to my TVpaint workflow, going back to other programs was a chore. I tried using TVpaint for painting and again dived into understanding the engine and trying to mimic what I'm used to getting in other programs. I think now after doing a lot of testing of it's capabilities one of the reasons it feels a bit less intuitive at times and feels perhaps less "capable" to paint in TVpaint coming from other programs(setting aside the 8 bit color limit) is the lack of Opacity control linked to Pen pressure. (Also for the record im not saying it's terrible or anything, but I think if this could change it would be a massive addition)

Maybe other people could chime in, and I'm very open to be corrected, but I think the above quote is wrong regarding comparing Tvpaint's Opacity and Power, and other programs Opacity and Flow/Density etc. In my testing in other programs, Power in TVPaint definitely behaves as flow does in those programs, and having a pressure control with opacity is very noteworthy. One reason, is having opacity set to Pen Pressure(as opposed to flow) allows you to build up gradients in a single continuous brush stroke with increased pressure in a way that is very useful and intuitive in these other programs. The only comparable thing I've found in Tvpaint is using a custom brush set to Alpha Max, but this seems to have a less fine tuned pressure curve and the build up on say a hard round brush is harder to control in my testing.

I also mainly worked with custom brushes as I thought after a while due to less parameters/customization that the other brush categories were only simpler versions of what you could do with Custom brushes. However, after coming across a thread that talked about the limit of 8 bit software and rounding errors and why the other brush modes (air brush, water etc.) exist, I took another look at what they can do. After using them more, it's most evident with the Air Brush, but I've also been pleasantly surprised at the water brush. It is quite capable once you really play with the settings and adjust them as you work, one of which is in adjusting opacity with it and the way the Power interacts with the build up of the edge/profile, and I feel like if you could adjust the Opacity with pressure on this it would be fantastic.

So in short my question related to the testing in that other thread: is it a limit that unless there is major rework to the brush engine in TVpaint, having an Opacity Pressure connection is impossible? Or is it just buggy the way Opacity and Power interact, which seemed to be what that thread was saying, and there could potentially be a solution?

Edit:

Here are some visual aids to the point.

A good video from CTRL+PAINT with the difference between OPACITY and FLOW in photoshop.


A video I made hopefully demonstrating, that while there are some workarounds that approximate an Opacity/Pressure control, they still leave something to be desired as in the original post. Also that the explanation given in the past that Power in TVpaint is Opacity in other programs, I believe is incorrect(again glad to be corrected). To sum up again the point of the original post is simply asking if this is something that can be added or not in the current engine. If not, hopefully in the future as I think it would be a great addition.


Re: Pressure Sensitivity Opacity Brush Connections

Posted: 04 Nov 2024, 16:26
by Peter Wassink
i made a custombrush with an opacity responding to pressure for you.

But i am still struggling with floating panels that disappear...now the panel to export custom panels is hidden somewhere.
tvpaint gets greyed out and i cannot find the exportpanel anywhere i have to press escape .. so now i cannot export the panel for you, because of this floating panels bug.... a bit ironic....

Re: Pressure Sensitivity Opacity Brush Connections

Posted: 04 Nov 2024, 16:42
by kelanhordos
Thanks Peter, I would be interested to look at it when you get that working, I posted in the other thread where those options are located.

I thought of this for animation brushes, and made one myself as well before posting with 100, and then 1000 levels going from 0-100%, and I still found it didn't function like opacity in other programs and built up too quickly? But again, would appreciate any input.

Edit...I realize maybe you meant the custom brush Opacity connection, that was something else entirely that I am a bit confused about, as it seems to still be Power. I think the easiest way to demonstrate the difference is when you have an opacity/pressure connection in another program, if you double back in the same brush stroke, there is no build up, whereas there is even with a opacity/pressure connection in Tvpaint on the custom brush. I will record some screen grabs to maybe help my original post when I have a minute.

Re: Pressure Sensitivity Opacity Brush Connections

Posted: 04 Nov 2024, 16:59
by Peter Wassink
i went back to v11 (still prefer that version!)

i made an animated brush of 256 steps and connected the animation to pressure
an important option is the alpha diff blendmode which neatly blends the opacitys together...
That drawing mode was custom made to fit the painterly animation style of Hisko Hulsing
opacity brush.jpg
opacity brush.jpg (42.25 KiB) Viewed 72 times
opacity brushes panel.tvpx
(1.26 MiB) Downloaded 8 times

Re: Pressure Sensitivity Opacity Brush Connections

Posted: 04 Nov 2024, 17:14
by kelanhordos
Thanks Peter. Ya, I forgot in the original post to mention alpha diff, and only mentioned alpha max. It does works better for a single stroke build up, but then there is a problem with building up multi strokes over top of each other, especially of different colors. For lack of a better term, the strokes "eat" into one another and the way faint falloff works, and your original strokes are kind of absorbed into the original instead of painted over. I should have waited until I had time to post visual tests to support my original post, but have been strapped for time, I will try to do so asap. So, I still feel like the opacity connection would be ideal, but appreciate the help.

Re: Pressure Sensitivity Opacity Brush Connections

Posted: 05 Nov 2024, 19:10
by kelanhordos
I've updated the original post with a video, hopefully demonstrating the point and clarifying where some of the difference lies with using animated brushes etc. as workarounds.