CNODES are used to connect or associate Degrees-of-Freedom, for the stiffness matrix. CNODES are also used to connect items graphically. There are two opposing situations in the "graphic space":
1) You connect a pipe nozzle to a vessel, using computed stiffnesses. In this case, you also want the CNODE to also connect the graphics (geometry) so the model looks right. Here you want CONNECT_GEOMETRY_THRU_CNODES turned on.
2) You associate two DOFs that are not at the same location (like you did with your hanger). In this case you want CONNECT_GEOMETRY_THRU_CNODES turned off, otherwise you foul up the geometry of the model.
You cannot satisfy both #1 and #2 in the same model. You have to turn off CONNECT_GEOMETRY_THRU_CNODES othewise the geometry is wrong. This may result in (graphically) disconnected pipe segements. You can usually address this with dummy rigid elements.
For example, in your case with the hanger, from the top pipe drop down with a dummy rigid element of the proper length, to reach the hanger location on the bottom pipe. Then when you specify the hanger on the bottom pipe, the CNODE will be the lower node of the dummy, not the node on the upper pipe. If you model this way, you can then keep CONNECT_GEOMETRY_THRU_CNODES turned on.
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Regards,
Richard Ay - Consultant