translation data from ARtoolkit marker

Question

How would you obtain the translational data from a marker using ARToolKit?

I know that ARToolkit can give you the transformation matrix, but I'm having difficulty getting the translational movement.

For example, when I move the marker to the right, the object that I draw on the screen will also move to the right. However, I don't want to draw the object on the marker, since it will be rendered in a scene using OpenSceneGraph. The purpose is to try to create a virtual environment, and interact with it without using too much keyboard interaction. Of course, the marker data would be obtained through a webcam.

Answer 1

Well, if ARToolkit gives you an osg::Matrix (or something that can be turned into one) you can try to decompose it: http://www.openscenegraph.org/documentation/OpenSceneGraphReferenceDocs/a00403.html#b4a03cf47d938467121d0560d8284c6e

and get the translation you want out of that.