Convert global coordinates to local coordinates

[binyan]

Given a vector expressed in global space and a mesh, how can I get the position of this vector within a mesh local space?

Or, alternatively, how can I get a parent position within a child local space?

 

Update:

Just figured it out... It is simply vector.subtract(Mesh.getAbsolutePosition()), right? 

 

Update2:

Ok it's not... Because it doesn't take in account the mesh rotation. 

[binyan]

Think I came up with a solution:

 var m = new BABYLON.Matrix(); mesh.getWorldMatrix().invertToRef(m); var v = BABYLON.Vector3.TransformCoordinates(vector, m);

Is that right? What I did is simply an inverse of local->world transformation process.

[GameMonetize]

Absolutely!

[getzel]

Hello !

This is very useful for those who want to transform a vector into a mesh's space.  But I don't know why you use Matrix.InvertToRef.

I understand better this function :

       var vector = new BABYLON.Vector3(100,0,0);
        var m = mesh1.getWorldMatrix();
        var v = BABYLON.Vector3.TransformCoordinates(vector, m);
       mesh2.position = v;

 

 

[adam]

17 hours ago, getzel said:

But I don't know why you use Matrix.InvertToRef.

Your example seems to be getting the global position given the local coordinates.

Binyan was getting the local coordinates given the global coordinates.

[KamranK]

this fixed my problem but I do not understand how it worked. How is the inverted matrix able to give back local coordinates