You don't. This is why i was not so sure we should have this feature. But all the other slicers had it and at some point we also had to participate. Because if we don't, people keep using the lack of a "realistic" rendering as an argument why Cura is falling behind.
If you want a perfectly right layerview, it's going to take a loong time to build. You would need to take a whole lot of physics, material flow, deformation, etc into account.