Hi I have modelled a ladder deck steel bridge for incremental launch analysis. I am trying to run geometric non linearity using “TH3, CTRL ITER 3 V2 1” but it shows negative determinants. the model runs well in static analysis and it runs without error in “NONL”. I changed V3, V4, V2 quite many times but I am unable to resolve this error. Any guidance on how can I investigate this error?Grantham_49m_truss_master003_Launch_recover.sofistik (1.5 MB)