octomap, velodyne and clustering

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I would like to know if it would be possible to process velodyne data with an octomap.

I am not interested in building a huge map of the environment, i.e. for SLAM. But I need to know my surrounding for immediate planning and obstacle avoidance, let say about 70m around the robot. That means the octomap would be a rolling map in a way. I would need a resolution of about 10-20cm if possible and an update rate close to real time (i.e 10Hz).

In particular I am really interested in the ray tracing ability of the octomap.

Besides, I want to be able to retrieve the obstacles from the map, so that I can track them and classify them (cars, pedestrians, bicycles, etc). This would require some sort of clustering technique, i.e. connected component analysis...

Also, my planner requires a list of obstacles coordinates, so I was wondering if I could query the map to return me all the voxels (at a certain resolution) that are occupied. I saw that the search function was taking a x,y,z coordinates, does it mean that I'd have to do a triple loop search on a volume of voxels and test for occupancy? I feel there could be a better approach...

If velodyne data is too much data, I guess I can consider downsampling (spatially and temporally)... So I'd like to know what others people here have tried before I get started.