It is not possible to design a SHAPE‑THIN cross-section due to invalid symmetry. What is the cause and how can I fix it?

Answer

RF-/ALUMINUM checks the symmetry of general cross-sections and compares them with the SHAPE-THIN evaluation if activating the "Determine symmetry by module and compare with SHAPE‑THIN definition" check box (Figure 01).

Figure 01 - Dialog Box Details, Check Box Symmetry

If both methods provide different results, the corresponding error message appears (Figure 02).

Figure 02 - Error message

Usually, there are small inaccuracies in the SHAPE‑THIN cross-section. Thus, the cross-section Sec‑1.du9 shown in Figure 03 is not absolutely symmetrical to the Z‑axis: The Z‑coordinates of Node 1 and Node 4 as well as Node 55 and Node 60 do not match in the second decimal place.

Figure 03 - Different Z-Coordinates of Cross-Section

SHAPE‑THIN classifies the cross-section as asymmetrical, but RF‑/ALUMINUM as monosymmetric to the z‑axis, so the error message shown in Figure 02 appears.

The SHAPE‑THIN cross-section should be checked for symmetry. When modeling in SHAPE‑THIN, it is useful to only display one side of the cross-section and to create the other half by mirroring. This is also shown in the video.

Keywords

Failed design Symmetry

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