• Adobe After Effects Expressions

  Basics expressions (Scale and color)

  Posted by Florian Schneider on November 8, 2015 at 6:45 am

  Hello people,

  It’s the first time that I add a post on this website. Hopefully won’t be a boring issue and that I’m in the right place !
  I just began to work on motion design projects and I always been deeply interest by the expressions, I don’t really know the basics so sorry if I’m a little bit lost.

  What I want to do is really simple.
  I want to use the expressions to change the color of an object and also change his scale.

  Clearly what I want to do is :
  – Create a new solide, let’s say a square.
  – With the expressions, change the rotation of it via the index. So add the expression “index”. Then if I duplicate my square, the next one would have +1 in rotation than the first one. I want to duplicate this square a lot of time.

  But before to duplicate the first one, I need two expressions in more.
  – The first one would be on the scale, I want my squares to be smaller one after one until 0%. Like that, the first square will have 100% of scale, the next one 99%, the third one 98% (…).
  – Finally, I want them to change color as well : The first one would be white, the second a little bit darker, the third one more darker until that the final one would be really dark.

  Can you see which effect I want to have ?

  I’m really beginning, I can do that on myself, by hand. But… I’m so interest to win some time with the experessions that for the first time I want to understand how it works.

  Thanks a lot, if you have some recommendations, links, books “How to start with the expression” I’m totally interest !

  Thanks a lot !

  P.S.: Sorry for my English

  Kalleheikki Kannisto replied 10 years, 10 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Kalleheikki Kannisto

  November 8, 2015 at 10:05 am

  Hi Florian and welcome to the world of expressions!

  For scale expression you could use

  Math.max(0,101-index)

  For color it is easier to put the expression in an effect value like brightness. I have AE rendering at the moment so I can’t verify the values, but if brightness values that you need go from 0 down to -100 it would be

  Math.max(-100,1-index)

  These would work for 100 layers. All subsequent ones would be 0 in scale.

  The first place I would check for expression basics is Adobe TV.

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