How to Retime Camera with Baked Keyframes

[Mark Walczak]

Hi everyone,

I have a camera with about fifty frames of baked animation from a 3D program. I need to find a way to take those baked keyframes and retime them. I know in Cinema 4D, there’s something called the time track that allows you to retime pre-animated elements in a given scene. Is there anything similar in AE?

Thanks a bunch!

https://vimeo.com/explosivegraffix

[mathew fuller]

Precomp it and then time remap the precomp.

My Work:
https://www.morecompletefx.com

[Conrad Olson]

Create an expression control that lets you control the retime.

Create a duplicate camera, with no animation

Hook it up to the animated camera with an expression that references the position of the original camera, from the frame specified by the expression control.

Keyframe the expression control to do the retime.

The new camera will be able to get values from in between whole frames from the original camera based on the animation curve.

I don’t have After Effects in front of me and haven’t used expression in it for a while so can’t give you an example but this is how I would set it up.

—

conradolson.com

[Greg Burrus]

Old thread but I thought I would post my solution based on Conrad’s response since it helped me. It took me a bit but I figured out at least one way to do it.

Duplicating or creating a new camera as he said with no animation.

Then link the values together of what has the baked animation:
thisComp.layer(“Camera Name”).transform.position (or whatever you are trying to control)

Then add .valueAtTime():
thisComp.layer(“Camera Name”).transform.position.valueAtTime()

Inside the valueAtTime function link it to a slider on a null:
valueAtTime(thisComp.layer(“Camera Control”).effect(“Slider Control”)(“Slider”))

Next make sure to divided it by your comps Frames per second or the timing will be off : valueAtTime(thisComp.layer(“Camera Control”).effect(“Slider Control”)(“Slider”)/24)

Final will be:
thisComp.layer(“Camera Name”).transform.position.valueAtTime(thisComp.layer(“Camera Control”).effect(“Slider Control”)(“Slider”)/24)

After this, you need to connect your footage from your render. I have all of my composite layers in one precomp. Turn on time remap and link that to the slider that is Controlling your camera.
thisComp.layer(“Camera Control”).effect(“Slider Control”)(“Slider”)

Also divide it by your frames per second:
thisComp.layer(“Camera Control”).effect(“Slider Control”)(“Slider”)/24

Now it all should be linked up together and one slider should control your camera and your animation.

My case was needing to have simple text animation pop up over the animation at times where I added an extra frame to hold the 3D render cause it would be silly to render out multiple frames for holding on screen.

Though I could of done this with precomping as another poster suggested but that would require multiple comps with the camera duplicated(instances would work if I didn’t need to retime) or modifying the bake camera keyframes (I’ve done this before) but I always fear I may select one I don’t need.

This way allowed me to keep all of my controls and animations in one comp so I could see things at once. Though I could split it up easily as well and just link controls in another master comp if I wanted.

Hope this may help someone in the future.

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