octree in gpu raycasting (volume rendering)

Hello,
i want to implement an octree in my volume renderer for empty
space leaping. i know how to build that octree and in the most
books about volume rendering thats the recommended data
structure. my question is, how to use this octree then for rendering? the volume is uploaded to the gpu in a 3d texture.
what to do next ? i have absolutely no clue. Someone there
who can help me please ?

regards,
lobbel

Nice paper from the last Siggraph Asia over here…

http://www.voreen.org/files/sa08-coursenotes_1.pdf

I’m not up on all the techniques but this seems to cover a lot of them.

Thank you, but i miss some details. To color code the sub bounding volumes came up also in my mind. but what to do. the octree has to be traveres, i know. but when the starts at a beginnging point
it needs to know where it is and if the ray has to jump in the sub volume. i dont have any idea.

regards
lobbel