A Study of Chemistry in The Sims 2

Previously I had empirical information here because the real attraction code is buried at a level below normal mod code. I finally braved the LUA which calculates attraction and figured out the full attraction system.

The first thing to understand is attraction is both balanced and unbalanced. If Sim A has 50 attraction to Sim B, but Sim B has 20 attraction to Sim A, the game will average these two values and report it as 35. Because of this I'm not specifically reporting unbalanced attractions, but rather reporting the averaged values. I'm not sure one-sided attraction affects anything other than a one time check for very low chemistry.

The numbers I obtained are useful only if they can be translated to bolts. Per the game constants, bolts correspond to the following attraction levels:

  • -1 bolts.....-25 or less
  • 0 bolts.....-24 to 0
  • 1 bolt.....1 to 34
  • 2 bolts.....35 to 89
  • 3 bolts.....90+

Note that the actual chemistry numbers such as those reported by Cyjon's Debugger don't always correspond and sometimes chemistry bolts change even when raw chemistry hasn't. My guess is this has something to do with "attraction markers" which I haven't investigated yet.

Note that in the following pages I call the Fortune aspiration Wealth since I abbreviate aspirations to one letter in my own notes.

With that, let's look at how each factor affects chemistry.