An example of the ambient shadows, seen here with Telamon.
Screen Space Ambient Occlusion (also known as SSAO or ambient shadows)[1] was a Roblox feature released on January 28, 2011, along with Updated Graphics. Roblox would automatically turn off this feature if it detects the user receiving less than 30 FPS because of the shadows.[2] It could be prevented from turning off by setting Quality Level to Level 21, setting Antialiasing to Off, and not using OpenGL.[3]
Removal[]
It's believed that when Dynamic Lighting was released, ambient shadows were removed to encourage people to use the new lighting system. As of December 19th, 2020, there is no confirmation on why ambient shadows were removed.
Around January 9th, 2021, Roblox implemented HBAO (Horizon-Based Ambient Occlusion) to make the render look better, as it is an improvement to SSAO. However, for a few weeks it was disabled due to various bugs. Later on January 29th, 2021, it was re-implemented after fixing them.