Hi, Im attempting to analyse the flow through a diffuser which is symmetric about the midplane. So i have modeled a 180 degree sector to be analysed. But when running the case the solver always exits with the following error message. "The symmetry boundary condition requires that the boundary patch mesh faces form a plane or axis. However, face set 2 in the symmetry boundary patch 'symmetry' is not in a strict plane, which means that at least one of its faces is not parallel to the others."

I have checked the face and edge projections for the mesh but still encounter this problem..

Anybody have any suggestions Thank you

you can change in expert parameter to increase tolerance to say "10" degree. But you'd better double check your model to make sure you don't make any serious mistake that leads to your issue.