OptoDesigner photonic simulation modules support both waveguide cross-sections (mode solvers, multi-physics solvers) and full top-view layouts (propagation simulations). Mask layout and simulations are tightly integrated; for example, a slice through a mask can be passed to a process flow visualizer and from there to a mode solver on the calculated local cross-section. In addition, propagation simulations can be done on a part of a mask layout. Different propagation algorithms can be mixed and matched in one single simulation run for optimal simulation speed and accuracy.