Determining the 3D coordinates on a polygon's surface
 

Hello everyone,

I'm after a way to find the 3D coordinates of random points on a cube polygon.

I've created a cube polygon and dragged it somewhere in the scene. Now I obviously have its centre's coordinates, and mathmetically, should be able to determine the coordinate of any point of its surface but that would be troublesome.

Is there a way that I can find the coordinates of any arbitary point on the surface by clicking on it?

Any help would be appreciated - M

follow up
 

I was thinking maybe i can create another small polygon (1x1x1) and attach it somehow (automatically) to one of the surface of the main cube polygon - does that make any sense by any chance! :)
Thanks.
M