# quaternion problem

Hey guys,

I'm detecting cylindrical objects in a point cloud and want to use a service to save all the data of the cylinders and make them accessible to other nodes. What i'm having trouble with is that i want to visualize the cylinders in rviz and therefor i need the center point and the quaternion, but the segmentation function of pcl gives me two vectors, bottom point and a direction vector. I already managed to compensate the offset from the bottom point to center point by simple vector calculations and to get the quaternion from the two vectors but i need the bottom point and don't want to save all of this information.

Is there a way to save just the bottom point and the quaternion and "slide" the bottom point along the quaternion up for half the cylinder hight, whenever i want to visualize it in rviz? Or do you think that the data size wouldn't be problematic if i have to save up to 1000 cylinder datasets containing two 3Dvectors and quaternion?

cheers

Alex

Edit: To sum it up: Is it possible to calculate the center point with just the bottom point and the quaternion?