help plz with particles ?


    Feb 28 2010 | 6:52 pm
    Hey!
    so im new to max msp and this forum, what got me interested was watching this video :
    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!

    • Feb 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.
    • Mar 01 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 :)
    • Mar 01 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
    • Mar 03 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 :)
    • Mar 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 :)
    • Mar 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
    • Mar 15 2010 | 7:16 pm
      thank you =) works much better now!
    • Mar 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
    • Mar 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
    • Mar 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!