GIMP Version: 2.7.4
Operating System: Windows
OS Version: Windows 7 64-bit
GIMP Experience: Intermediate Level

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Hello. I was wondering if anyone can tell me or guide me to a source with information about using the Brush Dynamics and Layer Groups in GIMP 2.7.4 (the unofficial release from Partha)? I'm confused on what they do.

Thanks for that link. As for brush dynamics, I believe it is for tablet use, but I don't know what it does or why it's important. And how it differs from the previous settings they had for GIMP.

I don't think it's added anything new, It's just setout differently.

I read up on a few things there i also didn't know.
For instance - Last, but not least a Web-page plug-in was added to render any web page into an image using Webkit. Developer: Mukund Sivaraman

Open any home page in Gimp, convert to an image slice it up and code it.
Gimp needs a better default image slicer though.One that works with selections, and not guides.

Not only... of course there is no pressure in a mouse, but distance, direction, velocity and randomness still apply.

On the contrary, there's loads of new settings in the new version.

Here is a grab of the two key ideas in the dynamics.



You first set up a matrix in which "inputs" (pressure for tablets, velocity, angle, random, etc...) get mapped to which paint dynamic attributes (size, hardness, colour, jitter, etc).

The default relationship is 1:1 for each input:attribute, but can be changed in a little curve editor (right hand size) to get a vast array of effects, each which can be named and saved as a specific dynamic. These dynamics can also get attached to tool presets...

-Rob A>

Thanks for the attachment, but I have no clue what any of that means lol Can you explain it a little more? What does adjusting those curves do?

@Iacertile

This is relevant both for tablet and mouse users, but in the example of having a pressure sensitible tablet, adjusting the curve for "Pressure" determines how brush properties chances when you apply more pressure and in what way. If you, say, define opacity with a straight line and tie it to pressure, the harder you press, the more opaque the brush will be, and vice versa. If you tie the input "velocity" to the brush "radius" using some sort of curve, moving your mouse/pen with various speed will dynamically change the radius of the brush depending on the speed your currently moving it at. And so on. A real pencil features all these properties naturally, which is why it's very important for a brush engine to emulate it in order to achieve optimal flexibility.

This is a very powerful functionality for painters and everyone else who do brushwork. It's a long awaited feature of GIMP (in the interim, programs like MyPaint, which specializes in offering even more brush dynamic functionality has come along to fill the void though).
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Griatch

@Griatch So you mean that if you were to link velocity with brush radius slow movement would produce a small line and fast movement would automatically produce a bigger line without needing to adjust the maximum brush size?

i.e. If you set up a velocity to size relationship, the default curve is small velocity -> large size, large velocity -> small size. if you reverse the curve it will be small velocity->small size, large velocity->large size. If you make it a curve the relationship between the two will become non linear. If for example you mane the curve look like an upside down V, your size would be large for slow, getting smaller as you speed up, then getting larger as you get even faster.

-Rob A>

Yes, for example, exactly what the high/low speed does would depend on how you relate the two (the curve in the brush dynamics window) So if velocity is on the X-axis, and brush radius on the Y-axis, a curve going upwards to the right would mean that the faster you go, the larger the brush radius. If the curve slopes downwards to the right instead, it means the brush get smaller the faster you move your mouse (this is a more common mapping since it is part of mimicing an ink pen).

Edit: I.e. just what RobA just explained but in other words.
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Griatch

@Griatch - you ninja'd me there and I didnt see your post "above the fold" (or on the previous page... technically).

Good explanation!

-Rob A>