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Rotation around an arbitrari Point
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@germangda

Posts: 7

NGLNewbie

Sun, Jan 6 2013


Hi, I'm trying to achieve rotation of meshes around an arbitrari point for example 0,0,0. The thing is that mesh rotation happens on it's own coordinate axis. So in oder In order to do that I need to

  1. Translate rotation axis to coordinate axis
  2. Perform rotation
  3. Do inverse translation

This is what I've got

[object translateToX:0.0 toY:0.0 toZ:0.0];
[object setRotateX:rotateX];
[object translateToX:?? toY:?? toZ:??];

So the questions are. How to I calculate the inverse translation? Is there an easiest way to achieve this kind of rotation? Below an image of what I am trying to achieve.

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@dineybomfim

Posts: 571

NGLAdmin

Tue, Jan 8 2013


In response to: @germangda

Hi buddy,

Seems you're doing a large path to do a short thing.
The question is very simple. You must use the pivot. Just it.

But remember that pivot affects not only the rotation, the position and scale are also affected.
So, for example, let's say that you want to rotate the mesh about the point x = 1,0, y = 0.5, z = 0.25.
Set its pivot to 1.0, 0.5, 0.25 and then move the mesh position to -1.0, -0.5, -0.25. This will make rotation, scale and position works around the specified pivot (1.0, 0.5, 0.25) however the mesh will stay in the original position (0.0, 0.0, 0.0).

That's it.
100% like this - 1/1

@germangda

Posts: 7

NGLNewbie

Tue, Jan 8 2013


In response to: @dineybomfim

Woo! I thought that pivot was not working but I see that I was using it wrong, I will try it, thanks man!
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