Sims 3:0x073FAA07

Signed assemblies, encrypted .NET assemblies. They function as the game scripts.

These are the scripts that run when a Sim interacts with an object, or another Sim, or just performs its own inner metabolic processes.

Currently no way is known to get the game to accept piecemeal overrides, so global hacks for a particular assembly as of 6 / 6 / 2009 are having to replace the entire set - meaning that you can only have global hacks for a particular assembly from one creator at a time.

It is probably possible to create new scripts for new custom objects, however. Technical details coming later.