Simple 2D Problem

I've been getting used to doing 3D analysis (Linear elastic) but could not get results to converge. As the part has rotational symmetry, I thought I could do a simple axis-symmetric analysis of a 2D face (slice through the part). I've meshed it, but keep getting an error box in Code_Aster, when selecting a mesh in the wizard: "at least a group without nodes need to be defined on the selected object".

This is probably an extremely rookie error, but I can't for the life of me figure out how to resolve it. Any suggestions would be extremely well received!

Also, around which axis does Code_Aster assume symmetry? Does it assume 360-degree symmetry or 180-degrees? Any pointers to examples/tutorials would also be appreciated as I haven't come across any for this problem case (axis-symmetric)

Cheers

try searching on AXIS in the documentation there is info there.
If memory servex correctly its about the Y axis with quantities defined on a per radian basis & of course its equivalent to 360 degrees.
about the group thing not too sure, have you got groups of elements defined ?

I've the same problem with the message... in last version of salome seems you've to create group before gointo to aster