How to compute Rot matrix so box is always perp to camera, like an avatar?

When I move around in simplegame, I would like a box to always be in front of me (like I'm carrying it, or in this case shooting it).  How would I compute the rotation matrix for the box given the camera direction?  In many ways I guess this is an avatar, but I need the rotation matrix for jbullet's sake.  Any advice appreciated.

The following seems to work:



Matrix3f m =…

m.setColumn(0, cam.getLeft())

m.setColumn(1,cam.getUp())

m.setColumn(2,cam.getDirection(())

m.invert();



In my several posts I have found my answers but I'm usually worried they're hackish in nature and a solution already exists.  Any clarity - on any of my posts - greatly appreiciated.

Maybe an Billboard Node is what you are searchin for. Haven't used it yet, but it is supposed to be pointing to the camera direction automatically, so you always see the front.