View Full Version : Feature Request: BRUSH CONTACT options for Custom Brush

11-24-2019, 07:41 AM
I think this feature request would be a game changer. It would be for me anyway. I don't think any other popular digital media software does this yet... but I could be mistaken.

Feature Request:

Brush Contact Controls for the Custom Brush

A user set range of stylus pressure starting at zero up to some usually small percentage is devoted to brush contact features. Above this range of pressures the brush has "full" contact, in this range some portions of the brush are deemed not yet to touch the canvas (as explained in a few variations below) i.e. some pixels within the custom brush head are simply ignored (zeroed out). This zeroing should be applied after the custom grain effects are taken into account but before the interaction with canvas grain effects are applied (and prior to opacity and size setting which vary with pressure are applied).

The following picture illustrates the pressure curve (for illustrative purposes, not in the interface), and how a custom range could be set by the user. The illustrated range 0-35 is probably much larger than would be realistic, but it is arbitrary.


Note this feature would be separate from other pressure set options such as opacity, size, etc. It's purpose is to provide a new zone at the very low end, which simply nulls, or zeros, or otherwise attenuates or removes portions of the brush from the computations at that pressure...i.e. sets a range simulating a brush coming into contact with the canvas to simulate different shapes or textures caused by the brush contact surface.


Bit Map Brush Contact

This setting would impose a zeroing thresholding on the pixels of the brush whose percentage "value" falls below the relative pressure percentage (within the brush contact range) being applied. E.G. For 0 pressure all bits of the brush would be zeroed out. At the max contact pressure of the brush contact range, none of the pixels of the brush would be zeroed out. In between 0 and the max contact pressure of the brush, only pixels of the brush with percentage "values" above the pressure expressed as a percentage of the max level would be deemed in contact (used in the brush computation) while all pixels of the brush with percentage "values" below the pressure expressed as a percentage of the max pressure would not be deemed in contact and would be completely ignored or zeroed out.

For example, if the brush contact range was set to 0-10%, then when the stylus applies 5% absolute pressure (50% of the max contact pressure of the range), then only those parts of the brush with a brush head value of >50% would be in contact.

The following illustrates this. Note, other options like size and opacity can be applied on top of these changes.



As the following shows this causes a brush head to simulate bristle length as shown here:


I realize this is crazy brush head shape but I hope it serves to illustrate.

This option could include a "gamma adjustment" tweak so that the trend varies in a hard or soft or linear manner as a function of pressure. Another "softness" option could take it from a simple thresholding to a softer opacity type calculation... i.e. its not simply binary contact or no contact but varies from full contact through partial contact to no contact.

Tilt Brush Contact

Taking the simulated brush head as having an angle this could be used with the above or as its own separate option.

The idea is that stylus tilt direction magnitude are known and a flat brush head would contact first at the closest point to the tilt direction and sweep directly in line until the whole brush was in contact as shown here:


The most efficient algorithm would be hard thresholding in a swept line in the opposite direction of the tilt, but options could include a spatially soft linear opacity rather than a hard spatial thresholding... and gamma adjustment to adjust how the sweep occurs as a function of pressure could be included as well (concave, linear, convex).

As noted above this could be done in tandem with the bit map brush thresholding...

I forgot to mention for the tilt options, at max tilt the entire brush contact range is used, but as the tilt reduces the tilt aspect shrinks ie the faster the threaholding sweeps (smaller pressure range) and at zero tilt of course one expects simultaneous contact rather than a sweep.

BIG REQUEST... I know it ....

but if it could be done it would be a game changer for me !! and it would keep ArtRage ahead of the competition!!




12-12-2019, 11:31 PM
It's in another software, I don't know if I can tell the name here, but on my videos on youtube you can find it.
I'm agree this would be a great feature, I thought about it since artrage 5, and it would be a game changer for mee too.
The question is, is it something that can be done or no, and what would be the performances of the pc requests afterthat for the software to be able to work with it. But I dream of it too^^