Unity has a famous limitation to convex colliders for performance reasons. Universal Colliders is a fast approach to overcome it.
Usage
This Unity package aims to be as simple as possible. You simply have to add Universal Collider component to your mesh, and select a resolution. The collider will be auto-generated.
Internally, it uses an OBB Tree to generate a set of bounding boxes enclosing any shape.
For more details on the internals of Universal Colliders, you can have a look at Universal Colliders for Unity.
You can find the online documentation for the project on universalcolliders.houmgaor.com.
As of the time of writing, I removed the project from the Unity Asset Store to focus on other projects. See Where did go Universal Colliders?