Ever since I bought my tablet, I've been looking at ways to use it to its full potential. But it seems that brushes in GIMP are pretty basic and I can't quite find the information needed to make better ones for myself. I looked on the web for brushes, and most of those I find don't use x/y tilt or pressure (and GIMP itself doesn't seem to be able to use rotation, which some of the newer pens and tablets out there support). The great majority are just “stamps”.
I'm really surprised that most of the brushes are not vectorial but images. To me, it made a lot more sense to be able to use, say, an SVG format brush, complete with gradient and colours support rather then the static images. This means that, if I want a custom brush, a star, as seen by Hubble, with that “cross” light and the X light and the actual star, I have to create several images of the same kind and depending on the way I draw each image for pressure control, I may end up with a poor quality (sharpness) brush.

So far, so good, I am able to create a few layers and save the files as a GIH brush. But the question that I did not see answered anywhere is “How many pressure levels do I have to draw?”

If I draw a round brush, similar to the “Circle” brushes, with pressure control, I would like it to have bigger sizes the harder I press my pen. If I want to have a continuous look, I would have to make a 10px wide brush, then an 11px brush, then 12px, etc. otherwise the brush would look choppy. I could not find anywhere in the manual or the web how to create pressure sensitive brushes and what is the biggest number of layers that you can have? My tablet has 1024 pressure levels, does that mean that the biggest number of layers I could draw is 1024, if I wanted to make a very fine brush?
The tablet I bought comes with a Flash tutorial explaining how the X/Y tilt comes in handy when using the airbrush tool, for example, with a round brush. If you hold it perfectly vertical (0 degrees X and Y axis) the form of the brush is a round. If you tilt it, it becomes an eliptoid which emulates the airbrush tilt. I read the GIMP help files in regards to creating a three-dimensional GIH brush, but again, the amount of layers possible is not specified and the whole section does not seem too clear for me. It talks about a 3D matrix and shows you some numbers, but forgets to specify the corresponding settings in the Save as GIH dialogue.

What if you want to create a brush that has both X/Y tilt and pressure? What does velocity mean? How do I correctly create a brush with X/Y tilt that is cursive (the help section explains with a brush drawing the numbers 1234, but in practise I can never see the number 3, just 1 for 0 degrees, 2 for 90 degrees then 4 for 180 and 270 degrees). Most importantly, how can I create these brushes without losing the quality of the image through cubic scaling, sheering and perspective transformations? How can I reduce the work I have to put in when dealing with a fine brush that may end up with hundreds of layers?

If anyone knows the answer to these questions, it would be greatly appreciated. Right now, I feel like I can't use the tablet I brought at its fullest potential.

I also wonder why gimp could not just use SVG file as brush., with or withouth "parasities" as gradient pattern and colour

But gimp has a system to create resizable brush and there is a tutorial from Griatch t hat explain how to use them at best with graphic tablet

they could change not only size but they could also be rotated, tilted and blurred on the fly...
what i find a weird limitation is in the shape...seems as is not possible create them with "holes" inside (as for any sort of ring shapes...) as i didn't saw how to create vectorial "spiral" brush... (i don't even know if this in theory will be possible if so i could not guess how to do it in pratice...at least that seems impossible from the brush editor

And even more then vectorial brushes i miss any kind of "fractal" brush...(a example of fractal brush is "optipiscus" included in PD pro that is a commercial(not too expensive for the quality but commercial and ... sure not open source) painting program for win (well not only painting it could be used to edit image too but its basic streght is for painting).

Are very useful to recreate shapes or pattern that are sort of natural fractals as could be grass, brushes, tree brunches and spiral shapes just to give few examples

I know about GIMP's resizable brushes and have read Griatch's tutorial (it's how I started looking at the brushes and what you could do), but as you well noticed, you cannot create non-symmetrical shapes with it.

In your grass leaves example, you could easily use a few different leaf shapes and then use the tilt capability to change their orientation. I promise that, if I find out clearly how to make pipes, I will create a tutorial on it, because frankly, the possibilities it opens are huge.

Maybe you can still find a my old topic about animated brush

My problem was that i could NOT see a way to avoid them too change in a too random way

(you can go only "ahead" along a stack but not go "back"to previos one neither you can "freeze" the brush to use the same several times...neither skip one or more brushes)

That make me thing of a very advanced car with futuristic feautures but with few thing missed as steering wheel, brake, and reverse gear, few things but absolutly needed to drive somewhere.

If i create a Gif brush that could progessivly scaled up or blurred, then i can't see any way to use it in a "reverse direction",going backward from the big to the little or from blurred to sharpened)

And that seems to me a big limitation as for fancy dream car with no steering wheel and no brake ...how the heck to "drive" it ?

I suppose this is the reason why this powerful tool is not so used, it miss the most basic controls (it go ahead on a y, x or z direction but could never turn back or stop at the right point)

In more simple words possibilities of animated brush are almost endlessy.

But withouth the simple option to invert direction or tempoarary stop the progression ...or skip a few brushes without using them...

well withouth that the endless possibilities are multiplied for 0 chances of pratical use

And when you multiplied something for 0 result never change will be allways[highlight] 0 [/highlight]... as 0 for usability

I don't have the time to try this out right now, so I don't know if it would work in practise, but "forward/rewind" control could be obtained with directional + incremental brushes. For example, moving from left to right uses an incremental brush with layers 1, 2, 3, 4 and moving from right to left uses an incremental brush with copies of layers 4 3 2 1.


---------->
1 2 3 4


<---------
1 2 3 4

Based on the help file, there seems to be a way of naming the layers (according to http://docs.gimp.org/en/gimp-using-anim ... ushes.html ) and arranging them so that what I wrote above should be possible.

Now, the amount of work needed to accomplish such simplistic control is a different story, but GIMP seems to be very little concerned with simplifying work, which is probably why Photoshop is still preferred by a lot of people. It's the first time I am deceived by it and it "hurts" all the more because I want to use it.

That come to my mind too but is a lot of extra works to be done for each set

more it doesn't really solve. the 2 other very basic problems

A) suppose i have the right brush that i want use for 4 strokes ...how to? Seems no way to do something so simple!

(i refuse to think that

1)stroke it on a new layer created for the task
b)saving the output as new gbr ,
c)switch to new gbr brush ,
d)give 4 stroke with it
e ) then switch back to the Gih brush
f )repeat all this anytime is needed any extra stroke with same brush

could be a pratical soluction...not in real life)

2 Suppose i want use some very little and some very big brush, but skip everything in between, also this seems almost impossible

(well, impossible in a reasonable amount of time...in theory it could be done creating a "waste bin layer" where to stroke 1 by 1 all unneeded "in between" brushes...but in pratice that doesn't look as a pratical and logic solution )

I also fear that similar solutions( if heard )will become legendary in the little word of the "usabilty expert" making them laught for years, and with a good reason

To quote House in one of the episodes where he's in a plane and asks the help of a few travellers:

"OK, you will be the 'No' person, you keep opposing everything I say. You will be the 'Yes' person, you keep agreeing with everything I say. And you... you question everything I say."

I am willing to investigate the usability of these brushes some more and your negative input only makes me more curious, so it's good. What we need now is the person questioning everything we say

Actually, this is an invitation to everyone to provide their input and suggestions to how you can create animated brushes, and hopefully we will come up with:
1) as few and simple steps to create an animated brush that uses:
a) vector of the brush (the "angular" option)
b) pressure
c) x/y tilt
d) speed (? I am not even sure any tablet could use this)
e) all of the above (well, 4 at a time, since it doesn't seem possible to have more than 4 ranks)
2) The possibility to automate this task through a script.

The upside would be that this could be integrated into the help files and help others.

To use again the analogy with a car

it seems as to say that there is a solution to allow car's driver to turn to left

and that just with the simple addition of a new steering wheel, dedicated to to turn left,
then could be needed another one for right turn in case drivers are so esigent to pretend to be able also to turn to the right and not only to the left

As for go backward like for parking that could be easy fixed just by unscrewing the engine ,put it upside down , fix again in the new positions....and then parking (of course only going backward, since to go forward even for few inches will be needed to turn again all the engine upside down )

I hope somebody could find a more pratical way.... luckily this not happen to cars but only to gih brushes

PS Punkie we post toghther feel free to add again your request to the end where could be more visible

I really hope that could bring something...my previous search bring me only to the name of the main developer involved with the gih brushes but then i give up

let me now if something useful pop up

[highlight]Animated Brushes[/highlight]

This tutorial is a work in progress, this is the reason for its presence in the General Help section. Help with explaining the various options would be very welcome, don't hesitate to participate if you can or spot a mistake. It is also an advanced topic that requires you knowing more than GIMP's basics, so the tutorial may be hard to follow for beginners. This guide was written based on observations with version 2.2.14 for Windows.

The first thing you should read is the manual. The section “The GIH dialog box” deals with all the options that you have when creating animated brushes. Hopefully, the manual will improve in that regards, but before this happens, here are a few more tips and instructions.

To create an animated brush, start with a new file of the needed dimensions and save it right away in XCF format. Animated brushes can take the colours picked by you if you save the file as a grayscale image, or have the same colours you used to create your brush if you save them as an RGB image, so take your pick now. If you create a greyscale image, it seems you have to make your brush's background white and not transparent. The white will be interpreted as the transparent colour and black will be the picked colour at full opacity when you use your new brush. In the case of coloured brushes (such as the Pepper brush that comes with GIMP's default brushes), transparency is transparent.

[highlight]Random Brush[/highlight]

A good example of a random brush would be confetti. GIMP already comes with an animated brush called confetti, but we'll create our own.
First, decide how many different confetti you need. Let's say you're happy with 10 different shapes. Start by creating the first shape in a new layer, “First shape”.

Next, you have few choices: you can create the subsequent layers as new empty layers in which you draw again a new shape or you can duplicate and transform the first shape (rotate, scale, shear, perspective). Depending on the subject of your brush (in our case confetti paper bits), it may be faster to hand draw them if you'll just use small lines like the GIMP's confetti brush, but for more complicated shapes, duplicating and transforming may be better.
Once you have your 10 layers, save your work in the XCF format then save a copy in GIH format. You can save it in your brushes directory directly if you want to preview it in another file.

The GIH dialogue box comes up after you have specified the name of the file.


The spacing is how often the brush will repeat. I put mine to 1000 just to test this new brush. The description is what appears in the brushes dialogue; you can use the same name as the file to make it less confusing.

The cell size has interesting properties, but we'll go back to them later. For now, change the dimensions to reflect your image size.

Number of cells will reflect the layers that can be used, starting from the top of the list, so you can use only 5 of the 10 created layers if you wanted. The first cell will also be used to create the preview for the brush, the image that appears in the Brushes dialogue. The size of the first cell is what influences the the spacing, for example, if your first cell is 100x100, the second is 300x300 and the spacing is 150, the space in between the two shapes will be 150 pixels (that's the length of the line you draw using this brush, so if you circle in place for 150 pixels, the shapes will overlap, as expected).

The “Display as” information will be revisited a bit later.

Dimension determine the number of different effects you can create with the brush, maximum of 4.

Ranks has to reflect how many cells are to be used by the Random effect in our case. You need to make this number equal to the number of cells for the new confetti brush, but if you want, you can further reduce the number to say, 3 cells used randomly, which leaves 2 more to play with another effect (dimension).

Once you press OK, the file will actually be saved. Don't forget to press the “Refresh” button in your Brushes dialogue so you can start using it.

The same brush could be done in a different way: create a new image, test.xcf, of 150x60 pixels and “Add Alpha Channel” to the Background layer. Using the “Show Grid” option from “View” menu, imagine the file is split in 2 vertically and 5 horizontally:


Now save it as a .GIH file and watch the GIH dialogue:


You can see I modified the cell size to read 30x30; this has created a table of 2 rows and 5 columns, as indicated in the “Display as” information. The number of cells is still 2 * 5 = 10, out of which I am going to use 10 cells to create my random effect. This way of creating your cells can come in handy later on when dealing with multiple ranks, when having tens of layers would get messy really fast.
The cells are numbered from left to right and top to bottom, so the first cell is “a”, the second is “b”, the fifth is “e” and the sixth is “f”.

[highlight]Incremental Brush[/highlight]

To create an incremental brush, you would follow the same steps as above, except selecting an “Incremental” rank, obviously. The peculiar thing is that, the first time you use the brush, the count starts from the second cell instead of the first cell, as would be logical. If you interrupt the stroke when you reach cell 5, for example, the next stroke you do with this brush (even if you change tools or brushes in between) starts with the cell 6.

[highlight]Angular Brush[/highlight]

The manual says the first cell in use is the 0 degrees angle (from middle of the image to top-middle of the image) and the others just follow the formula 360 / number_of_angular_ranks. That's not entirely true, at least not in Windows (I have read about this being a bug in Windows, if someone using Linux can confirm it works properly for them, I'll update this). It seems to be more like 15 degrees (from middle of the image toward top-right). The last cell is used for the 345 degrees angle (from middle toward top-left) and 0 degrees.

Let's try to create a brush that has an arrow in the direction of your stroke and it changes based on the angle you draw at. If using few cells for this, you would end up having a pretty ugly, choppy result. The finest brush would have 360 (is that possible?) cells, but who's crazy to do that many? Besides, the computer resources used by such a brush would probably require way too many computer resources.

So I'll test with 24 cells, which should give me a smooth-ish (360 / 24 = 15 degrees angle for each cell) brush.

First, let's start with a layer of 15x15 in a 90x60 image. Inside the little layer, I will draw my brush, an arrow. If I knew how to code filters/scripts for GIMP, the next steps would be very easy! If you can, please help!

Once I have my first arrow, going from the bottom middle of the layer to top middle of the layer, I move it into position 1. It would be so much easier to perform the next steps through code: duplicate this first layer 5 times into position 2 through 6, and rotate it by current rotation + 15 degrees for each layer (so cell 2 = 15 degrees, cell 3 = 30 degrees, etc.). Once you have the 6 layers, you duplicate layer 2 through 6 in reverse position from 8 to 12, flipping each layer vertically: cell 2 becomes cell 12, cell 3 becomes 11, etc.

We're almost there!

For cell 13, you need to duplicate cell 24 and flip it vertically. Duplicate cell 2 through 12, flipping them horizontally, into cell 24 through 14: cell 2 becomes cell 24, cell 3 becomes cell 23, cell 7 becomes cell 19, cell 12 becomes cell 14.

That's it! Save your XCF so you can come back and modify if needed, then flatten the image, add an Alpha channel to the Background layer and save as GIH. Choose the 24 ranks to be angular and a spacing of 50 if you want to test it properly.

As I said, on my Windows computer, the angle 0 (first cell) rarely appears and I have no idea what exactly influences it (not even holding down Ctrl+Shift helps); instead, the cell 24 (angle 345) appears when drawing perfectly vertical lines. But the rest of the angles appear correctly and I'm quite happy with the (albeit ugly-looking) brush. Since I don't think many people will have the patience to do this, I'm uploading the resulting brush, called “Test Angular” for those Linux people to tell me if it works better on their machines.

http://www.cyberpunksnation.org/Test-angular-brush.gih - The angular brush.

This is an interesting discussion. Nice to see a tutorial on this, Punkie. I'd say it needs even more images though, maybe even some theorethical illustrations of the concepts. It's not easy to understand how GIMP treats the ranks and cels and how it feeds it into the queue.

I'm swamped with research work for the moment, so I don't have time for a lengthy answer; but I think what's needed is a proper animbrush editor (could it be scripted?) that can take a brush template and apply a preset range of useful transformation to it depending on what sensitivity parameter you want to apply. Minute control should also me possible (like putting a few key cels and letting gimp create the matrix for you, filling in the matrix between the keycels for you with the precision you desire). In other words, something to hide away the boring and error-prone work of manually placing these ranks and cels in the grid.

By the way, the "speed" rank is the velocity at which you move your brush. You can have an ink brush appear thick if you move it slow and thin if you move fast for example. This works nicely also with a mouse and has nothing to do with the tablet.
.
Griatch

You might possibly be able to do some of that sort of thing with GAP. I have experimented a bit with GAP to make animated brushes, but haven't gone into any great depth with it.

There is also a plugin (linux only) that will take an image and cut it up into user specified sections and make a new multilayered image out of those sections. And another plugin that does the reverse that could possibly have application here. I have used the first plugin to make brushes with.

Home page for the above plugins.

Thanks guys, I was beginning to lose hope here

I'll add more images then, for now consider this as a draft copy, but sure, I'll add more stuff.

I'll also have a look in the next few days at that plug-in, and continue the tutorial. If one of you can tell me if that angular brush works fine in your Linux version of GIMP, that'd be great, you don't need a tablet for it.

That angular brush worked like a champ, the arrow points whatever direction I was painting. I am running Xubuntu Dapper and Gimp 2.2.14 compiled from source.

Thanks! Good to know.

I suspect I will have to finish my Linux From Scratch (http://www.linuxfromscratch.org/) installation to test the rest of the options though, since I tried the x/y-tilt and velocity and they weren't working properly (it did work a bit, but not as good as I expected). I had started a while ago, but it's not all that fun It takes a bit of time to compile X and the needed libraries for GIMP.

Okay...using your brush as a guideline, I used GAP to make a brush with 100 cells (which appears to be the maximum), so each arrow rotates by 3.6 degrees. I am not seeing a whole lot of difference in the rotation of this brush in comparison to yours, but then right now I am on my windows box at work and not on my home comp.

http://www.box.net/shared/r50pj3eo23