• Adobe After Effects

  Pasting mask shapes into z-space

  Posted by Rob Wolf on June 30, 2007 at 8:41 pm

  Hello,

  I posted a similar question a few weeks back, but the one answer I got was a bit off the mark. Let’s try again.

  I’m tring to make a object move around z-space in a spiral shape (imagine a butterfly flying around a flower).

  I have a spiral mask shape that I created in Illustrator. I can paste that mask shape as positional keyframes on the emitter, put that only gets the particle to travel in X and Y, not Z.

  I know that masks are always 2D, but is there a way to make the Z property take its value from the Y? I’ve tried pasting the keyframes into a 3D Null, parenting the object, then rotating the null 90 degrees. That didn’t do the trick. Any other suggestions?

  Also, the camera in this move should be stationary. It’s the object I want doing the moving.

  Thanks,
  Rob

  Darby Edelen replied 18 years, 10 months ago 3 Members · 3 Replies
• 3 Replies

• 

  Mike Clasby

  June 30, 2007 at 9:41 pm

  When you said, “I can paste that mask shape as positional keyframes on the emitter”, were you meaning an emitter for Particular?

  If so you can Alt click the “Position Z” stopwatch, then pickwhip to the Y of the “position XY” (just drag the pickwhip to the Y value only) to get a Position Z expression like this:

  effect(“Particular”)(“Position XY”)[1]

  Then if you want the Position XY to use it’s own X but ignore it’s own Y, try this expression on Position XY:

  value + [0, – effect(“Particular”)(“Position XY”)[1] + 240]

  I hacked it with the pickwhip so I’m sure it can be done cleaner. It just tells the Position XY to use it’s original value, then add zero for the X and subtract it’s own Y from itself. The +240 on the end just makes that the new Y, centering it on a frame 480 high. Change the 240 to whatever you want.

  If your not talking a Particular Emitter, be a little more spacific, por favor.
• 

  Rob Wolf

  June 30, 2007 at 10:02 pm

  Yes, I was referring to particul. Will give that a shot. Thanks!
• 

  Darby Edelen

  June 30, 2007 at 10:36 pm

  When I answered your previous question I was not told that it was Particular you were dealing with. Particular works differently with 3D coordinates than AE normally does. You can still use the Null and parent and rotate if you use a Light as the emitter and parent it to the Null.

  Basically, Particular doesn’t use a motion path the same way that Lights, Cameras and Layers do, it uses a 2D array for X & Y positions and a separate Z value while AE generally uses a 3D array for X, Y and Z positions.

  I wouldn’t recommend using an expression in this case because it can get confusing if you start moving the keyframes around.

  Darby Edelen
  DVD Menu Artist
  Left Coast Digital
  Aptos, CA

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