This is from the CS documentation in Max 8.
“The crowd-animation system in character studio is designed to simulate the behavior of real-life crowds. A crowd simulation emulates real-life situations by animating delegates (helper objects that act as representatives). You give the delegates overall guidelines on how to behave, and the crowd simulation calculates their motion.”
So it can be done, but I’ve never tried.
As for the character itself you would most likely want to have a design where if they look the same it makes sense. Like lizard aliens without any cloths.
Once you try to do natural people. Then they need different faces, cloths, body types, and gender.
We’re already doing a project like this at work. For a stadium of about 70 digital people. All coming from one custom character rig that supports parametrics. You need to build a custom pipeline, scripts, and organize data structures to pull it off. It’s a lot of work, and in the end viewers make very quick judgements as to how real it looks. If you have to fix an error in the clothing or face. It can takes days to transfer those changes to all the many characters.
In the end it never looks as good as working on just 1 character. You waste so much time just trying to get your crowd to look right that time is lost on details of the character.