Build region in viewport

It would be great if we could just build a small region in the viewport. It is very tedious to wait every time we make a small change in lighting with static lights.

The crux with that is that lighting of objects inside the viewport is also affected by objects outside the viewport.
This only considering the currently visible actors would yield unsusable (wrong) results.

I am totally in for this Feature, because it will be great to adjust rendering and lighting more effectually without waiting for some time, and I like to add some options for rendering too.

1- lights/ rendering presets save so its possible to save different lights renderings and settings and switch between them as needed or through blueprint.
2- adding visibility to light for objects or group, to be able to illuminate some objects with certain lights only or hide some objects from some lights for example.

Illumination of objects outside the viewport also affects the objects inside, but no problem. Imagine that you select a small area into the viewport and click on “Build region” feature: objects into the region would be rendered and affected by the illumination of the entire scene. And the render will disappear if you move the viewport or the cam.

Vray can do this (render region) and calculates the illumination of the entire scene in a small window. It is perfect to testing without long time waiting.

I think this is highly necessary to work with static lighting because currently we have to wait even 3 days to check if the result of light build is right or wrong … so I beg Epic to add some feature that makes it easier to work with static lighting.

Another possible solution: we can see the final result in real time working with movable lights, however, if we convert the movable lights to static, the result is different even after build lights.

A value of 30 in movable light intensity is not equal to a value of 30 in static light. This should be the same (after build) (I mean just the intensity).

When we modify the ambient occlusion from the postprocessvolume, we can see on the screen how the scene will look like, but we can not bring the same values to the world setting section. We should be able to do this.

(sorry for my English).