Forums > Jitter

help plz with particles ?

February 28, 2010 | 6:52 pm

Hey!

so im new to max msp and this forum, what got me interested was watching this video :

http://www.youtube.com/watch?v=plw3jNcaqjU

and wondering how they did it! so i already have a tracking system using my webcam that outputs co-ordinates..
but how can i make a plane (matrix?) with all the "images" ? ( in this case all the tiny umbrellas)
is it some sort of particle system? if so then how can i generate particles of a certain image on jitter?

thnx for ur time and help!


February 28, 2010 | 8:52 pm

You should have a look at [jit.gl.mesh] and search how to make textured quads. Then you need to set the position of the quads and [cv.jit.HSflow] will give you the movement direction of the user.


March 1, 2010 | 6:47 pm

thnx for the reply..ive taken a look at the objects.. still not too sure about how jit.gl.mesh ..do u know of any further readings/help into it?

thnx again :)


March 1, 2010 | 11:47 pm

The Jitter Recipe "Shatter" could be retrofitted to take an image mask instead of a scalar velocity value to do image-controlled particle motion. Below is an example using frame differencing, to give you an idea.

Andrew

– Pasted Max Patch, click to expand. –

March 3, 2010 | 10:12 pm

WOW…thnx alot for ur help and time …im still having a deeper look into that and checking out how i can edit it for my project..

p.s. i was actually JUST reading ur Jitter recipes :)..thnx for all the help and info ur presenting to us newbies :)


March 12, 2010 | 10:52 am

hey again mr. Andrew ..

so i did some adjustments to the patch (added a tracking system, import image instead of using live input and so on)..

the only thing i dont know how to adjust in your patch is how the "shattered" pieces act..i think its through the pieces_parts subpatch ..but cant be sure..

how can i control the distance they move away from the imported picture? and also the size of the shatterd pieces?

thnx alot for ur help and time :)


March 15, 2010 | 5:38 pm

The movement of the particles is happening on the upper right of the pieces_parts subpatch, and is really super basic force integration physics. The idea is, you provide a matrix of velocities (here jit.noise), and then add the velocity values to the position matrix and store the result (hence the named matrix). By multiplying the velocity matrix by a scalar value, you can alter the overall motion in the system. This particle motion setup is used a lot in the Jitter Recipes as a basic ingredient.

Andrew


March 15, 2010 | 7:16 pm

thank you =) works much better now!


March 18, 2010 | 4:59 pm

Very nice example, Andrew. Could your above example be easily incorporated into the effects chain of your VPS recipes? I haven’t quite cracked the code of using these more intensive opengl examples in a video filter chain. My chain goes something like this:

Video-> CPU effects (about 5)-> opengl effects (about 20..switchable on or off obviously) -> split into 4 seperate quad warp meshes (for cornerpinning) -> out to videoplane

Thanks


March 18, 2010 | 10:44 pm

@laserpilot – The trick here is to capture the OpenGL object to a GL texture that is then sent through the slab chain. You can use the @capture attribute for this. This is similar to how slab works internally.

AB

– Pasted Max Patch, click to expand. –

March 19, 2010 | 3:44 pm

Definitely an ah-ha moment. I remember seeing stuff like this recently with your Scene Processing recipe, but didn’t spend enough time with it. Additionally, i usually use the very helpful "clue" window to help me decode the multitude of messages that I can send these opengl objects and there is no clue for the capture attribute for some reason, although all of the others have one. I’ll give this a shot, thanks!


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