How do you turn on voxel realtime lighting model?

Where can you find where to change from the lightmass lighting model to the voxel-based realtime one?

It’s not currently supported in Rocket. The SVOGI lighting model was a prototype that inspired the Reflection Environment lighting model which is much higher performance and now used in UE4 titles. It uses a combination of pre-baked and real-time techniques for full-scene reflections.