I got an error when I run optimization.
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A fatal error has occurred during computations:
*** ERROR # 312 ***
In static load case 1
the compliance is negative or large -5.62632e+013.
Optimization/buckling analysis cannot be performed.
due to possible rigid body mode.
INFEASIBLE DESIGN (AT LEAST ONE CONSTRAINT VIOLATED).
*** SOME ERRORS WERE REPORTED DURING THE RUN,
*** PLEASE VERIFY RESULTS AS THEY MAY BE INVALID.
...
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But it didn't have rigids.
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