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The optimisation starts with the modified geometry as the first iteration. At the end of the optimisation the strut is removed and the rest of the structure completely integrated into the design. The algorithm might increase material elsewhere to compensate for the loss of the strut.
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You can check the status of the optimisation in the GD Status and get more information on Warning and Error messages. This can be done directly in the Post-Processing as well as in the Studies tab for an optimisation that has already run.
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