[enghamed]

I want to model a cylinder in ICEM and use O-Grid to mesh it. since it is symmetry I want to cut it in half and only export half of it to cfx and use symmetry Boundary condition.
I don't model the half from the begging becuase o-grid works better with a full circle rather than half.

Thanks for your help.

[PSYMN]

You should model it as a half OGrid... (or quarter ogrid for quarter symmetry) You just put a face on the symmetry plane. The 3DPipe tutorial (the first 3D hexa tutorial) covers this exact situation.

[PSYMN]

Although it is not the best way to handle your problem, if you did want to send a portion of a model, you should know that the output is based on the mesh in the *.uns file.

You should delete the elements you don't want to send (half in your case). But this would cause an uncovered faces (or Null pointer) error. So you also need to run the "Edit mesh (tab) => Check Mesh => Uncovered faces" (just run all the checks). It will find uncovered faces where your symmetry plane(s) should be. It will offer you the option to "fix". Choose that option and it will ask you what part you want the new shells to be in. Choose "New" and type in "SYMMETRY" (if you already have a Symmetry part, you can just pick that). This will face all those uncovered elements with shells in the SYMMETRY part.

Always run the diagnostics one more time to make sure you are good to go... Then output to solver. Since the output doesn't care about geometry, it only cares about elements, the shells provide the bocos and you won't have any problems. However, smoothing and interactive mesh editing does move nodes on the geometry, so if you want to use any of those operations, you should also create the "SYMMETRY" surface. You can do that before or after you delete and cover the mesh, but certainly before any smoothing or mesh edit operations on those SYMMETRY shells.

[enghamed]

thanks for your tips.
it helped a lot.