## Posted By

mattkenefick on 04/20/10

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# Get angle from object in 3D space

/ Published in: ActionScript 3

If you have multiple objects orbiting a 3D object and you want to determine the angle of a specific object, this will help you determine what rotationX you need to set your camera to if you want to be directly behind it.

Note: It works completely in 3d space. So if your Y, Z, X are not inversed or directly related to your comparison object, the angle will be a little off.

`var tempMatrix:Matrix3D = Matrix3D.inverse( new Matrix3D([0,0,0]) ); var vectorA:Number3D 	= new Number3D( 0,0,1 );Matrix3D.multiplyVector( *OBJECT*.getPlane().transform, vectorA );vectorA.normalize(); var vectorB:Number3D = new Number3D( 0,0,1 );tempMatrix = Matrix3D.clone( *CLICKED-OBJECT*.transform );Matrix3D.multiplyVector( tempMatrix, vectorB );vectorB.normalize(); var angle:Number = Math.acos( Number3D.dot(vectorB, vectorA) / (vectorA.modulo*vectorB.modulo) )*180/Math.PI; trace( angle );`