Converting to Global Space Without being Part of the World

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Converting to Global Space Without being Part of the World

Ommi

OK. Consider a cube. It is centred at P1(x,y,z). This is a position in global (world) space. Now the cube has a corner, (a,b,c), which is a point relative to P1. (Which is to say, I have a Spatial with a child Spatial.) I need to know the global position of P2 as I rotate the cube. To maintain my sanity, I'm only rotating the cube around its Y axis.

The cube is NOT part of a World, so I can not use the built-in GlobalTransform, as much as I'd love to.

I feel I could probably make it happen with some trigonometry, but I can't help but believe that there is some better way.

And for clarification, (x,y,z) is the position the cube would be in, were it to be added to the scene tree. (And I really hope I'm explaining this well!)

So to ask it another way, how do I get the equivalent of GlobalTransform, without actually adding it to the world?

pkowal1982

Try the test project.

Ommi

Hi! Thanks, but in the test project, all three Spatials are in the scene tree.

I don't have that, so GlobalTransform, ToGlobal, and GetWorld are all unavailable to me (and, indeed, throw errors if I try to use them.)

I need the equivalent of to_global, without having a World.

Edit:

But! I note that "Outside" in your test project doesn't touch the scene tree. I will try it!

cybereality

You would use the Transform class and the functions xform or xform_inv (depending on which way you are going). https://docs.godotengine.org/en/stable/classes/class_transform.html

Ommi

First, an apology to @pkowal1982 -- I did not look closely enough at the GDScript before my original reply yesterday. The parent_pos function provided bloody well does, in fact, do just what I was looking for. Thank you.

Second, I guess it is time for me to go through https://docs.godotengine.org/en/stable/tutorials/math/matrices_and_transforms.html yet again. While the replies certainly answer the question, the 'how it works' is obviously not sinking in.

pkowal1982

@Ommi No problem, could have add some brief description so you knew where to look. :)