The Reality Engine (Game engine)

Roblox Corporation's proprietary engine, designed to replace the open-source engine OGRE, announced as their new ROBLOX Rendering Engine in 2014 before an official title was decided.
"Our Reality Engine is the core of the Roblox virtual experience. It is a proprietary, high-performance, cross-platform, real-time simulation engine that dynamically scales fidelity to match device capabilities. The overall engine runs at 60 frames per second and can adaptively scale from an iPhone 4S to the latest gaming PC."

"The Roblox Reality Engine is packaged into our Universal Game Client, a single code base that can be built for all the platforms we serve, from iOS and Android, to Mac, PC, Xbox One, Oculus Rift, and HTC Vive."

The engine is accessible to users through Roblox Studio which allows users to design content, game modes or purchasable content, that will run in Roblox.
"Roblox Studio is our development environment for real-time social experiences, allowing creators to directly manipulate 3D environments, create physics-based interactive models, design complex geometries, and script game mechanics."