Add objects on a Frustum

When I try to move a cylinder on frustum along the z axis, it is not on the surface at the frustum( but small distance apart from the frustum) towards the tapered end of the frustum. How can I do this ?

A useful Trelis command is “measure between”. This can be used to determine distances between entities. For example, how far to move a cylinder so that it will be exactly on top of a frustum:

reset
create Frustum height 10 radius 5 top 2
create Cylinder height 2 radius 2

#measure distance between the top of the frustum and the bottom of the cylinder
measure between surf 3 surf 5
#in this case the distance is 6

move Volume 2 z 6