How can you make a custom shaped detection box that triggers an event when a player is inside?

So I want a script to be triggered when a player enters into one of the parts in a model. I need it to be a specific shape, and making an event for every single part of the model seems time-consuming.

Is there an event for a model that responds whenever a player touches any of the parts inside of it?

Also, something like region3d isn't useful since I want to use the ball shape or a cylinder shape