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Forums Boris FX Particle Illusion Too many variables at once?

  • Too many variables at once?

  • Jeff Bellune

    June 9, 2006 at 12:46 pm

    I have had good success animating an emitter to follow an object that is moving across a frame while the camera pans. Layer Offset has been my best friend.

    In one of my clips the cameraman (me) performed a significant zoom while panning. Once the zoom begins, layer offset and emitter position can’t keep up. The particle trail appears to freeze until most of the zoom is finished.

    I’ve added a force object to keep the appearance of the particle trail moving along, but there is still a noticeable bump in the animation when the force object becomes active. This is because of the magnitude of the strength parameter that is needed to overcome the effect of the camera zoom (about 1000 – 1200). The camera zoom occurs early enough in the clip that when I try to animate the force object’s strength from the beginning of the clip, the particle trail gets spread out so far, so fast that the effect is ruined. I increased the Number parameter to 800% and beyone, but I could not bring the particle trail effect back to normal.

    In AE7 Pro, I tried tracking position and scale of the object that the emitter will follow, but I couldn’t translate the 2D track into 3D position data. The 3D position data would have been converted to 2D position-only data for use back in pIllusion. I couldn’t figure out how to combine the tracker’s position and scale data to position-only data, either.

    I’ve tried animating the size and position of the force object, and I can smooth out the animation bump to some degree by keyframing those parameters. But the bump is still too noticeable.

    Does anyone have any hints or tips on how best to handle this situation, or have I done all I can at this point?


    The Focal Easy Guide to Adobe Encore DVD 2.0

  • Alan Lorence

    June 9, 2006 at 2:06 pm

    This is by far the most complex post here in quite a while! I’ve read it a couple of times, but I think seeing the problem would help most. Can you post a small movie of the problem? Feel free to email to support at wondertouch dot com if it’s something you don’t want to post publically.

  • Jeff Bellune

    June 9, 2006 at 6:21 pm

    I posted 2 clips. The first one is the animated emitter with no force object applied. The second clip is the animated emitter with a force object that has been tweaked to the best of my ability. Each clip is about 250KB.

    The clips are a WIP, so nice finishes like masking are yet to be done in AE.

    First Clip

    Second Clip


    The Focal Easy Guide to Adobe Encore DVD 2.0

  • Alan Lorence

    June 15, 2006 at 12:04 pm

    Sorry — looked at these and forgot to reply. It’s a very complex example, that I’m not sure you’ll be able to pull off without a fully 3D particle system. That camera zoom is a big problem.

    If this were my project, I probably wouldn’t use a force to fake the zoom — I’d probably add a second emitter with a bigger “zoom” property value and start it where the force kicks in. It would be based on the original emitter, but with the glow and possibly some other parts removed.


  • Jeff Bellune

    June 15, 2006 at 12:33 pm

    Thanks, Alan.

    I’ll experiment with a second emitter. I need to be clear on something before I do, though. Are you suggesting that both emitters will be active during the zoom and only one active before and after? Or should I turn one off when the zoom starts and turn the other one on?

    Also, will the “Active” property of the emitters/particles be a good place to start for turning off one and then turning on the other?

    (Sorry for the barrage of questions)


    The Focal Easy Guide to Adobe Encore DVD 2.0

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