• Adobe After Effects Expressions

  [SOLVED] Animate character opacity with xRotation

  Posted by Grégory Fauchille on August 18, 2015 at 6:45 pm

  Hi,
  I’m using Amortype to animate some text.
  I’m animating a text on x rotation but he is multiline, so if I set the rotation to 90°, the text is visible even if the animation didn’t start, because of the perspective.
  I wanted to hide the inanimate characters until they start to move. My idea was to synchronise the opacity to the xRotation : if(character.xRotation >= 90 )character.opacity = 0 else{character.opacity = 100};
  But everything I tried failed.
  I just begin to use expressions, I know javascript, but I don’t know the vocabulary of After Effect and the Adobe codex is really poor :/

  Thanks a lot,
  Greg

  Grégory Fauchille replied 11 years ago 3 Members · 4 Replies
• 4 Replies

• 

  Kalleheikki Kannisto

  August 18, 2015 at 7:26 pm

  Don’t know about Amortype, but if you were using the xRotation value of the type layer itself, the expression for opacity would be

  if(transform.xRotation>90){0}else{100}

  That assumes at least two things, one being that positive 90 degrees is the correct number, not negative, as well as that the camera is perfectly aligned to the same 90 degrees angle from the text rotation point.

  If the camera position is not correct for this to work, another option is to just keyframe the opacity at the point where it needs to appear.

  Third option would be to come up with an expression that takes the camera position in relation to the text into account to calculate the cutoff angle. That’s definitely more involved, and not knowing how Amortype deals with transformations, futile for me to try.
• 

  Grégory Fauchille

  August 18, 2015 at 7:37 pm

  Hi,
  thanks for reply, but it doesn’t work. I guess, if you don’t know Amortype, you can’t understand the problem. Amortype is a text effect to do some animation. I have to retrieve the xRotation of each character along the time in a text animation.
  With your script, I think it retrieve the xRotation of the entire text object.
• 

  Dan Ebberts

  August 18, 2015 at 7:52 pm

  You can’t get at the per-character rotation like that. You probably need to know what’s driving the rotation and use that same mechanism to drive an opacity animator (possibly with an expression selector).

  Dan
• 

  Grégory Fauchille

  August 18, 2015 at 8:21 pm

  Hi,
  thanks, that was a great idea, I have duplicated the animator and duplicated the Duration “effect” (just a cursor), so I can change the second expression to link to second duration and keep the link to the other shared “effects” (offset, frequency, etc).
  That work perfectly.

  Thanks a lot 😉
  Greg

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