Thank you so much for your in-depth information. It's interesting to know how you set the story of Judith's daughter in your game. Now I know why you can't accept that Judith is a co-star picked by the game.
If it's only once time and randomly, it might be okay to ignore or reopen the game to random again. But I think the co-star role is picked immediately after passing the audition, because in my game, the new director and co-star are generated at that time.
By the way, you can sometimes find the Sims from the movie studio in Other Households and delete them. So that will generate new Sims to appear instead.
I didn't use the delete method, but when I found an unwanted director or co-star, I exited the game without saving and playing the audition again. When I get Sims that I like, I keep them and save them.
I don't want to delete those co-stars to get the new one because they are part of my game already. I made over every outfit and befriended them. I still want them to be in the studio, but I just want to switch the co-star choice to be other actor sims in my game.
So, after knowing that fixed co-star is a thing, I can only accept it until I can find the other method to change the co-star without deleting.
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I used mods like "Show Sim Info" or MCCC to check the hidden trait or career level of these co-stars, but I can't see specific traits to make them co-stars. Their career are all level 1 too.
However, I found that
- Actors who are generated by the game to only practice acting, but not being a co-star, have acting skills over level 5.
- Actors who are generated to be co-stars have a level lower than 3 (or they start from 0).
I may try to add a sim who is an actor but has no skill, and see if the game picks new sims. But right now, I will try to get the movie gig, which is the rank that I haven't tried before. (I've just reach career level 8)
With the other active careers such as Scientist and Detective, I only see 1 or 2 of my other Sims on the lot. I was told it's because of how the game will staff certain levels and fill roles but I don't know it in depth.
I have 2 scientists from different households, and when I play with one sim, another one will appear as a co-worker. If not counting active sim, the scientist co-workers are 5 sims. I haven't made more scientists yet, but I guess that if there are more than 5, the game will pick randomly.
Sorry for the long discussion, but I want to share what I observe, which may be only in my game. However, your reply can provide more information about co-stars and co-workers from other experiences. It's useful for me. Thanks a lot!