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N
Noah5CDE
Inspiring
October 20, 2021
Question

Precomposing a null object and its orbiting layer changes its position.

  • October 20, 2021
  • 2 replies
  • 2094 views

I have an atom orbiting an earth which is parented to a null object. I'm trying to precompose this animation so that I can duplicate it and flip it to the opposite side creating two orbiting atoms. But when I precompose the layer and the null, it changes position on the screen. All these layers are 3d including the new precomp. I've tried so many different ways that I feel I'm missing something more important.

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2 replies

R
Community Expert
Rick GerardCommunity Expert
Community Expert
October 21, 2021

The basic workflow is flawed. I would use two nulls, tie the X, Y, and Z rotation of the slave null to the rotation null with an expression. Here's the expression for Y rotation on the Slave null:

 

value - thisComp.layer("Orbit Null").transform.yRotation

 

 Then all you have to do is arrange your comp like this:

It is going to be a lot easier to adjust both the position and orientation of each orbit. The trick is changing the orientation of the Slave null.

 

The problem using a duplicate pre-comp is that the 3D space for the nested comps and the animation is going to be identical when you turn on collapse transformations. You are way overcomplicating the problem.

 

I've uploaded my comp for you to take a look at. Took me all of 10 minutes to set it up.

 

In the future please embed your images by copying and pasting them to the reply field, or use the toolbar, or just drag them into the reply field instead of the buggy and difficult to see "Drag & Drop files here..." area. You should also reveal the modified properties of the problem layer by selecting them and pressing the "u" key twice as I did so we can see exactly what you did to the layers. It makes answering questions easier.

    N
    Noah5CDEAuthor
    Inspiring
    October 21, 2021

    Ok gotchya I appreciate the tips a lot. In the future I'll use the U key to solo the modified properties and stop using that drag and drop box for screenshots. I'm going to give this another try- the correct way. I appreciate you taking the time to build that example as it's very helpful. I'll update soon.

    R
    Community Expert
    Rick GerardCommunity Expert
    Community Expert
    October 20, 2021

    If you collapse transformations on a nested comp that contains 3D layers, the active camera in the main comp will be used to render the 3D layer positions in the nested comp (pre-comp). If you do not collapse transformations and you pre-compose 3D layers and the active camera view has been modified at all, the apparent position of the pre-composed layers will appear to change because they are now 2D taking their position from the default camera in the nested comp.

     

    Generally, when you pre-compose 3D layers you do not also make the nested comp 3D in the main comp. All that is necessary is to collapse transformations to get the main comp camera and lights to interact properly with the nested comp.

     

    I hope that helps. 

      N
      Noah5CDEAuthor
      Inspiring
      October 20, 2021

      It sounds like it made sense to me but I tried creating the precomp with tranformations collapsed and it still happens. I'm attaching screen shots that should be linear order of my operations. The second screenshot is the same frame so you can see the difference in position.

      Andrew Yoole
      Andrew Yoole
      Inspiring
      October 20, 2021

      In image 6, if you change the Precomp 1 layer to 3D what happens?

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