Controlling 3D Layer Y rotation with Ramp

Adobe After Effects Expressions

Controlling 3D Layer Y rotation with Ramp

Posted by Scott Smith on April 22, 2015 at 1:50 pm

I lifted this code from ECAbrams on Youtube:

sourceLayer = thisComp.layer("Transition Control 2"); sampleSize = [1,1]; samplePoint = transform.position; colour = sourceLayer.sampleImage(samplePoint,sampleSize); x=colour[0]*100; [x,x]

What it does is use the source layer Transition Control 2’s color, evaluates the color, and picks a scale size to match that color. Here’s the video: https://www.youtube.com/watch?v=4OQN2mHQuD0

So I modified it a bit but I’ve run into a problem. Here’s the code first:

sourceLayer = thisComp.layer("control"); sampleSize = [1,1];
colour = sourceLayer.sampleImage(sampleSize); x=colour[0]*360; [x]

This had to be modified otherwise I run into errors. I’m applying it to a 3D layer to control Y rotation so I can do a card flip animation with a gradient ramp.

The Y does rotate but I can’t use the variable samplePoint = transform.position because I run into an error at colour = sourceLayer.sampleImage(sampleSize,samplePoint)

Now I imagine this is because I’m using a 3D layer and sampling a 2D image and that’s the reason I can’t sample the transform.position.

Anyone see a good way around this? Right now all I can think is to duplicate each layer, hide them, and then pick whip the Y rotation of the visible objects to the duplicates’ scale, and use the above code so that the ramp controls the scale which in turn will control the visible Y rotation. But I was hoping just a few lines of code would be easier :).

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Joshua Russell replied 11 years ago 3 Members · 2 Replies
2 Replies

Dan Ebberts
April 22, 2015 at 3:40 pm

What is it that you’re trying to do exactly?

Dan
Joshua Russell
April 27, 2015 at 9:52 pm

I needed to replicate this in a project I was working on today. The issue is that you are pulling your 3d layer’s position, which is an array containing 3 numbers, and putting it into a function that can only accept 2 numbers. Check out the attached expression code for a workaround.

Notice we are filling “samplePoint” with the x and y position values. This may not be the best way to do it but it works.

sourceLayer = thisComp.layer("control") sampleSize = [1,1]; samplePoint = [transform.position[0], transform.position[1]]; colour= sourceLayer.sampleImage(samplePoint, sampleSize); x=colour[0]*360; [x]

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