If I move a sim from a different world into a house in an already existing world I’m playing right now, will he interact with the new world without me playing for him? Like for example, will he go to the bar or gym? I want my sim from this world to meet up with him so they can get in a relationship, have kids, etc., but I don’t know if they’ll meet.
@austinr55 yes, to answer your question. I do this a lot. One thing I sometimes do is to put them in a spot and then switch to my played Sim if I'm having trouble getting my Sim to find them to meet up. Sometimes they can be difficult to find, you don't get all the townies in the same place at the same time and sometimes you're travelling from place to place hoping to run into them somewhere.
Or if this fails I get either of the Sims to travel to the home of the Sim I want them to meet and I introduce them so they are added to their contacts and can get in touch with them easily. Sometimes I have them walking around the street at the time they finish work or sometimes they just brazenly knock on the door and say Sul Sul!
Edit: This also works if one Sim is moved into Other Households and/or doesn't have a home lot. Except obviously they couldn't be visited to meet up. They can still be not currently in world then provided they turn up at the same time and place as your Sim then they can meet.
You can also create a large household and split people out, put them in Other Households without a lot and still keep friendships or familial links and relationships. I often do this to create friendships, families and romantic relationships.
As @simsplayer818 said, yes! It's hit or miss, but the game seems to favor "your" Sims for walkbys, etc., so keep them in "your households." Contextually, if the Sim you're trying to meet has a high fishing skill you can hang out at the fishing spots, etc. If they have fitness--more than level 4, I think--they'll be at the gym when you go, or will jog past your house, etc. Artsy Sims seem more likely to spawn at the Museum. Etc. The game does populate NPCs/walkbys contextually by skill/trait. They also might be at bar night, unless they're loners.
If you have the Get Together pack, you can put both Sims in a club, and then start a club gathering. This guarantees it!
If you're able and willing to use mods, LittleMsSam has the SimDa dating app and you can send your Sim on a date with the other Sim and say they spotted each other's profiles on SimDa.
