[Simon Björk]

Thanks for your reply Dan, I will try to do some more research on the subject. Out of curiosity, how come you don’t think it’s possible with expressions?

[Simon Björk]

Hi Dan, thanks for your reply. After thinking about it a bit more I understand that it might not even be possible (the corner pin not being a rectangle for example).

However, there might be other ways to get to the effect I’m looking for. I’m having a shot with a ballon wobbling in the air and I need to attach graphics to it. I can just track the tracking marks on the ballon and attach the graphics, but that doesn’t rotate correctly as the ballon rotates. A corner pin is close, but not perfect.

Take a look at the “Comparing Transform to Rotation and starting our track” (free video) at https://www.digitaltutors.com/11/training.php?cid=203&vid=15417.

It shows the difference between having a simple 2d transform track to having 3d rotation. Note that no 3d tracking is used.

I’m pretty sure you can create the same setup in AE (no spheres, but with a couple of layers rotated you would have pretty much the same thing). I guess it works by converting the 2d position data to camera rotation and then using that somehow.

A script that converts 2d tracking data to a rotating camera can be found at: https://www.3dmation.com.

Do you think this could be done? Hard, but possible?

[Simon Björk]

Yeah, it can be a lot of layers and will take a lot of time to do manually. I have made a script that moves each layer 50 frames back. I guess I would loop through the time of each layer to find out which one that starts first so I can move that only 25 frames. Any idea how this would be done? My scripting skills are still pretty poor…

[Simon Björk]

Hi Dan,

I’m in this aswell. We’re trying to move each layer in the timeline back 50 frames. Except the first layer that appear in the timeline, that I only want to move 25 frames back. I thought I could find somehow what the first layer was by some kind of “time index”. Any ideas?

[Simon Björk]

Hi Dan, thanks for your reply.

I don’t get your expression to work either.

It does change the nulls position correctly if I change your “position + [0,0,thisComp.layer(“Camera 1″).transform.position.valueAtTime(-1)[2]]” to position + “[0,0,thisComp.layer(“Camera 1″).transform.position.valueAtTime(-1)[2]*-1]”.

However, I I want to animate my camera, I can’t. If I use the z-slider, it just moves the null and snap back to position 0.

Any ideas?

[Simon Björk]

Thank you for your reply Chris, but nothing happens with that expression, even if I add a slider to the null. Am I supposed to change any values?