Topic: Truncated Cone

I made Truncated Cone using 3D Engineering. When I want to assign the surface of the top circle, it said Error "The surface lines are crossing each other". And  I made two half circle and same Error.

Thanks!

Re: Truncated Cone

Please see Troubleshooting, 3.3.8 Problems with nonplanar surfaces, joints not inside macroelements, etc. and maybe also 3.3.2 Problem creating an opening (More than two surfaces are connected to the edge n.XX!).
If you still can not solve the problem, you can follow Troubleshooting, 2.1.1 to send us your model, sketches+description explaining what you like to analyze, and the exact steps leading to the error message.