Why does DOTS use have OnUpdate but not OnFixedUpdate?

Hey everyone, I just have a quick question on why DOTS has OnUpdate and not OnFixedUpdate? I was wondering why they wouldn’t do this for calculations that you don’t want to run on Update as performance-wise, doesn’t it waste processing if you don’t need to check something thousands of times a second instead of 50 times a second? I heard you can make physics a dependency to force it to run after physics. Would this be the reason for this? Thanks for helping as I had this bouncing around in my head for a couple of days now.

Because a system cannot belong to two different system groups - it must choose one. Either SimulationSystemGroup, PresentationSystemGroup or some other group using [UpdateInGroup(typeof(SimulationSystemGroup))] attribute.

SimulationSystemGroup is by default. So your code was probably running in “fixed” update already