   3D math question: Mouse X Y pointer to 3d space
  I have a 3D math question, to hard to solve by my self so any help would be much appreciated.I have thisMy camera transform, position and rotation.Mouse X and Y coordinates.What I want is the position of the mouse pointer in 3D space if the pointer has Y value 0.So, any pointers how to solve this?Thanks!   
  Hmm.. i think you should multiply your mouse vector (in the range -1.0 to 1.0) with the inverse projection matrix and you will get the mouse coordinates in world coordinates. But you will have to set Z to something, zero maybe, because your mouse pointer is more like a ray along the Z vector.   ;Quote:Original post by gardinHmm.. i think you should multiply your mouse vector (in the range -1.0 to 1.0) with the inverse projection matrix and you will get the mouse coordinates in world coordinates. But you will have to set Z to something, zero maybe, because your mouse pointer is more like a ray along the Z vector.Actually, multiply with the inverse of the view * projection matrix to get the coordinates in world space. And this can be done for (x,y,0) and (x,y,1) to get a ray from the near to far clip plane. Then you can do whatever intersection you need to do to determine whether you hit something.   