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Inspiring
October 13, 2022
Question

The behavior logic of the toWorld() and fromWorld() methods in Expression

  • October 13, 2022
  • 2 replies
  • 537 views

Hi all...

 

Can anyone explain the behavior logic of the toWorld() and fromWorld() methods in the provided scene.

https://drive.google.com/file/d/1VkAHg3bGehuDQlTyQpphz63yhwYpn6-0/view?usp=sharing

 

When the "Yellow Solid" layer does not have an ancestor, the behavior of the expression written for the Position property of the "Red Solid" layer is clear. 

----------------------------------------------------------------

var targetLayer = thisComp.layer(2);
targetLayer.fromWorld(targetLayer.toWorld(targetLayer.position));

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The position of the "Red Solid" layer is equal to the position of the "Yellow Solid" layer.

 

But when the layer "Camera 1" is assigned as the ancestor of the "Yellow Solid" layer, the algorithm for calculating the position of the "Red Solid" layer is not clear. The toWorld() method, as far as I understand, is designed to calculate the position of the child layer, which is the "Yellow Solid" layer???

 

And what should be the expression for the Position property of the "Red Solid" layer, when the ancestor of the "Yellow Solid" layer is the "Camera 1" layer, so that the position of the "Red Solid" layer matches the position of the "Yellow Solid" layer?

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2 replies

Mylenium
Legend
October 13, 2022

Correct. The camera and solid need to be children of the Null.

 

Mylenium

AnyONAuthor
Inspiring
October 13, 2022

It was obvious... lazy mind. Thank you Mylenium

Mylenium
Legend
October 13, 2022

They are generic matrix methods not specifically tied to parents or children. the camera is a special use case, since it's assumed as the world projection. What you have in your project therefore won't work. The proper way to do it would be to parent the camera and solid to a Null.

 

Mylenium

AnyONAuthor
Inspiring
October 13, 2022

What does "it would be to parent the camera and solid to a Null." ??? The ancestor of the created Null Object will be the "Camera 1" layer????