Seismosoft | Earthquake Engineering Solutions

dear sir !
it took alot of time to analyze a 3D model in seismo-struct ,
Can you explain the changes that will happened when i analyze a 3D model in 2D in seismo-struct .

Dear sir ! i am asking a question irrelevant but i need it's answer , i have design a 3D model in etab , which i want to analyse in seismo-struct . my question is can i analyse a 3D model in 2D in seismo-struct , Is there any changes in result will be occur or not , need an explained answer , Thank ...

dear z.gronti ,
Thank you very much , if you explain it , why it happens ?

what does it means during analysis and whats the solution for it ?
" Unable to apply the next load step. Analysis terminated
Total Analysis Time: 0h:3min:14sec "