what does the cyclic sym constranit actaully do?

[ozzkoz]

I'm having trouble with the cyclic symmetry constraint. I've got an axis symmetric part which I have created a quarter slice of and defined a cylidrical csys with z along the axis of revolution. The model has a cyclic constraint on the two plar faces of the 1/4 slice faces, a constraint which prevent translation along the z axis, and a constraint along the OD which prevents radial displacement. When I run the model I am told it is insufficiently constrainted. I would have thought that the cyclic sym constraint would prevent the 1/4 slice faces to displace normal to the constraint, which should constrain my theta direction.

Can anyone help me with what seems to be a very basic condition?