Light and performance for a game

[left venture]

Hello everyone 🙂
I am currently writing my bachelor thesis about lighting in video games. Unfortunately, I just came across a question for which I can't really find the answer.
There are different mobility settings for lights in Unity: Backed, Mixed and Realtime. To save performance you should mix all types. Now I was wondering if it makes sense if the main light source is backed, but characters are running around. Because these should make a dynamic shadow. Do all lights then have to be realtime, or is there a workaround?

As a side info: The work is connected to a project. My team is creating a top-down strategy game with a lot of characters running around (Tower Defense and RTS Combie)

[vast lion]

If you want dynamic objects to cast shadows, you will need a light source that's set to Mixed or Realtime - whether that's your main light source or a different one.
There isn't really a workaround for this.

Because of that, many RTS games (or generally, games that have lots of characters that need to cast shadows) may use blob shadows (see Unity's Projector component documentation) instead of actual shadows cast by light sources.
They might also mix actual shadows and blob shadows based on the camera's distance to a given dynamic object, but I'm not sure.