what is Screen space Global illumination (SSGI). When to use it? how it differs from other GI . (Thank you ! UE forum community is awesome. very supportive)
SSGI only provides bounce lighting for objects that are on the screen, meaning if you have a large red object that is bouncing red light into the scene, and you turn away, all the red light disappears.
That’s a pretty big limitation but it can work in some cases, such as top-down camera views. Those usually don’t have significant overlapping elements and objects take up less of the screen space so lighting changes usually aren’t as jarring.
I wouldn’t use it as the sole source of GI for a first/third person project, but it can be used to augment baked lighting, as it will provide bounce light and occlusion for movable objects/lights that otherwise wouldn’t.
So we can both use light baking and ssgi？
Yes