Light Shafts can be generated by directional lights to simulate the real-world effect of crepuscular rays, or atmospheric shadowing of atmospheric in-scattering. These rays add depth and realism to any scene.
The bloom method captures the scene’s color (including translucency and fog in-scattering) right around the light source in world space, and blurs it radially away from the light. This method does not really emulate anything that happens in the real world, but it is very controllable (not limited by density of fog) and looks impressive. The bloom method works best when there is an interesting bright area around the sun disk, like brightly lit clouds. This is because a bright sun disk will cause some aliasing since it is so small, and the blur is an image space operation.
Simple glass material ball creation: