The optimization calculates the von Mises stress and also the results inside the postprocessing show the von Mises stress.
The optimization works with different resolution levels. The first itertions are calculated on a coarse resoluton. With rising number of iterations the resolution gets finer. This means that the first iterations calculates much faster than the last iterations. As well as the size from the output data and the surface quality increases with rising resoultion levels.
Furthermore stress goal …
How does our optimization work: first few iterations coarse resolution with low stress goal …
Von Mises Stress