Treat simulation differently than other layers because it is different. There's only one per model, so don't need registry, it doesn't have user supplied fields so it doesn't need meta class, all it has are arguments, so give users a place in model to pass arguments
Treat simulation differently than other layers because it is different. There's only one per model, so don't need registry, it doesn't have user supplied fields so it doesn't need meta class, all it has are arguments, so give users a place in model to pass arguments