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moving edge collision

236 Views 3 Replies Latest reply: Mar 1, 2013 12:28 AM by fox_m RSS
sbonsell Level 1 Level 1 (0 points)
Currently Being Moderated
Feb 25, 2013 2:07 AM



I have an edge collision behaviour that I need to move around to follow the movement of the shape inside which the particles collide. The trouble is I don't want the particle generator to move with it - I want the particle generator to 'fire' particles into the shape from a distance.

I've always assumed an edge collision has to be attached to the particle emitter - when I try to move the edge collision it fights the move with all its might.



Motion 5, Mac OS X (10.7.4)
  • fox_m Level 4 Level 4 (3,325 points)
    Currently Being Moderated
    Feb 25, 2013 12:55 PM (in response to sbonsell)

    Your emitter belongs inside a group at some level... Add the Edge Collision simulation behavior to the Group the emitter is in. Make sure Affect Subobjects is checked in the behavior. Your emitter can then be moved around and the edge collision will stay in it's place (more or less -- it will actually vibrate some since the group dimensions change when a particle starts to leave the canvas -- the edge collision bounces it back into play though... You'll see what I mean. [If the Group is 2D, you can go into the Group inspector and turn on the Fixed Resolution property to stop that edge "vibration" if you want.])



  • fox_m Level 4 Level 4 (3,325 points)
    Currently Being Moderated
    Mar 1, 2013 12:28 AM (in response to sbonsell)

    It's actually not possible to shoot objects from an emitter *into* an Edge Collision zone. The emitter will always be "inside".  You can attach the Edge Collision to a parent group, and move the emitter outside its bounds (the canvas + Z space), but as *soon* as an object is emitted, it appears INSIDE the edge collision zone.  (Actually kind of cool really seeing all those objects line up one side of the EC space!)


    Your only option is to create an optical illusion.  One way is to set the Depth of the Edge Collision to a very large number (2500+) and position your emitter into the back (deepest) corner of the EC "space" (you'll need to be careful of the XYZ - easiest way is to set up with Perspective camera angle) -- angle the shot to the front opposite corner (for this you will need the emitter's Emission Longitude, Latitude and Range controls).  You will also need to use a Camera with the Angle of View set to 100+ (objects further away will appear noticeably smaller; closer objects will appear noticeably larger.) [Edit: you can have the emitter inside the EC space and still be off-canvas by increasing the Width of the EC, placing the emitter off canvas at the 0 Z-plane, but still within the bounds of the EC and shooting the emitter slightly back into Z-space. If the depth is great enough, you will still see the perspective bounces and depending on the angle, it could take quite a long time for any particles to reach the back end of the space (which you could elect to leave open so that the particles eventually leave the canvas...  if you see where I'm going with this.)]


    You will also need to make other adjustments as well (Speed of the emitter to overcome the distances, Longitude, Latitude, and Range should be "narrower".) You can actually obtain a good effect by doubling the width and height of the EC behavior as the "walls" deeper in space will be more spread out (you will not see closer objects actually "bounce"; but medium range to long range items you will -- with the perspective effect.)


    You can also set up your camera to "look at" a specific segment of the effect (so you can make adjustments to fit the bounds, but one side will always be out of the camera's view, unfortunately. Go with the Top. It's the one most people will accept as being missing... Left, Right, and "Floor" would be the ones to take preference.)


    Edge collision is very limited in Motion and those limitations can't be gotten around with the behavior itself... so **cheat!!!**


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