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Forums Adobe After Effects Expressions Negating the offset of a parent of 3D null

  • Negating the offset of a parent of 3D null

  • Navarro Parker

    November 18, 2015 at 6:01 pm

    I have a scene with a tracked 3D nulls. I’ve pickwhipped Particular’s emitter to a specific null using their x/y point control and separate Z parameter. However I’ve offset and scaled the whole scene (camera & 3D nulls) with a parent 3D null.

    Now the coordinates Particular is reading from the null is not the correct position.

    How can I subtract the offset the parent is introducing?

  • Kalleheikki Kannisto

    November 18, 2015 at 8:30 pm

    Did you link the nulls to the parent null when the parent null was still at default coordinates (center of comp)?

    If so, you can do the following to get the nulls back to their original positions:

    Unlink the nulls from their current parent (“Null 1”).

    Create a new 3D null (“Null 2”) at default position. Link the nulls to it.

    Add the following expressions to your “Null 2”.

    Scale:

    100*transform.scale/thisComp.layer("Null 1").transform.scale[0]

    Position:

    transform.position+transform.scale[0]/100*(transform.position-thisComp.layer("Null 1").transform.position)

    (If you linked the nulls when the parent null was somewhere else, I don’t think there’s anything you can do, as you need to know where it was when you did the linking.)

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