how to i feed the octomap into navigatio

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hello everyone, i have working on a navigation project i have a kinect camere i can able to create a point cloud with that and i convert that to laser scan and used for the navigation which is working fine . but sometime there comes a problem like ,if it is a chair the robot sometimes get hit with the chair beacuse the chair have thin leg. so i planned to give voxel grid as a costmap. but i didn't know how to create a voxel grid map and to feed that with the costmap . please help me out