• Adobe After Effects Expressions

  Clock Hand Rotate Expression

  Posted by Chris Holland on February 15, 2008 at 7:44 pm

  Hi,

  I am still learning expressions and am not that great at doing stuff without pickwhipping yet at all.

  I am trying to rotate a clock hand but I want it stop motion. So basically I want it to Rotate 5 degrees every 20 Frames without the interpolation so it cuts there.

  Is there a way to do this with the built in phrases or is it kind of like a custom expression and what wouild it be ?

  I am going to manually keyframe it now but as I think of things like this it is better if i can learn how to make stuff easier with expressions. for later.

  Thanks.

  Dan Ebberts replied 18 years, 3 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Dan Ebberts

  February 16, 2008 at 10:50 pm

  A rotation expression like this should do the trick:

  degreesPerTick = 5;
  framesPerTick = 20;
  value + Math.floor(timeToFrames(time)/framesPerTick)*degreesPerTick

  Dan
• 

  Chris Holland

  February 18, 2008 at 1:37 am

  Dan,

  Thanks for the response. Just a couple questions. Degree per tick and Frames per tick. Are they just random names you gave to those two things or are they Expression sprecific? Do they have to be written like that or could you have just put x & y but used those to be more descriptive?

  I would have had no idea to do what you wrote. Are there any books or documentation soley about expressions ?

  Thanks

  Chris Holland
  Editor
  Icarus Communications
  icaruscommunications.com
• 

  Dan Ebberts

  February 18, 2008 at 2:18 am

  Yes, those are just variable names I created. If I was doing it just for myself I probably would have used shorter names, but I wanted it to be clear what they represented.

  Chris and Trish Meyer’s Creating Motion Graphics with After Effects has a very thorough section on expressions. As of yet, no books dedicated to expressions.

  Dan

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