While trying to convert a complex surface to close/thick surface we often end up with an error "non planar geometry". how do you close or thick surface in such cases? any alternate approach or options available? please suggest. Thanks in advance.
If you have an open surface, the requirement by the close command is that the open end must be planar. You are probably getting the error because the opening is not planar. As Eric mentioned, you can get the boundary of the opening and fill the boundary, then join it to the other surfaces. This may not be the results you are looking for...so you may need to develop the closed surface in Generative Shape Design, etc.
