I'm playing around a bit with the genetics and wanted my breed to have their home where the light is. So I changed Stimulus to 'Reached Smell 1'. I thought it was that easy but I found the following problems:
- What to do with the instinct gene for the home? The light emitters classify as nothing but invisible. My solution now was to change them to 'weather' and set the instict to weather, too. Would changing of the emitters cause problems (with other agents maybe)?
Is there maybe another, easier way to tell the instinct that they get their comfort when following the light 'smell'?
- How does 'Reach Smell X' work anyway? Is it triggered when a certain amount of CA is reached or the maximum of the room or the total worlds? (Like, if I install a new room that has a new light maximum would their home location change?)
- Would there be a way to 'invert' it? To set 'darkness' as their home?
The way Creatures detect and interact with smells is a bit funky. I know what you're going through, because I've tried to do similar things in the past.
I'm not sure exactly how "reached smell X" works on its own, but I can tell you that if you want your Norns to approach something, the smell in question needs to be associated with an agent type. Norn brains are set up to run primarily on interactions with physical agents. For the most part, a smell is essentially just a "billboard" that tells the Norn where to find an agent of a given type.
One way in which you can see this limitation in action is what I call "oblivious Norn syndrome" (or ONS for short). If you create an object that smells like food, but is either invisible or just some other type of agent, Norns will pace around that agent but completely ignore it. Even if the agent is some other edible object, like a piece of fruit, they will still ignore it! Their brains connect "food smell" to "food agents", so they will keep doggedly looking for a piece of food until they are either sufficiently distracted by something else, or until they die.
This kind of behavior (expecting an agent to be associated with a smell) extends to Norn Home Smell too: there is a specific, visible agent called "Norn Home" which Norns approach when homesick, and this agent is what produces Norn Home Smell. If Norns can't see the Norn Home agent, or if the smell emitter is a different agent type, they will fall right into ONS: pacing back and forth helplessly as they look for something they either can't see or don't recognize.
Now here's something that might be able to help you: Norns only know that the "Norn Home" agent is what produces Norn Home Smell because the game stores associations between smells and the agents that emit them. In Docking Station at least, you can change or create new associations using the CACL command. The structure of the command, as depicted in the CAOS Documentation, looks like this:
CACL (command) family (integer) genus (integer) species (integer) ca_index (integer)
So if (for example) I wanted to make the Hand smell like food, I could run this command:
CACL 2 1 1 8
You can have your Norns approach light more effectively if you tell the game that the "light smell" is linked to a certain agent type, and tell them to approach that agent. I'm not sure the inverse would be possible, though, since "darkness" even in the game is simply an absence of the "light smell".