Object fade in and LOD cross-fade
There are two ways to perform the fade. The first option is to simply enable blending and fade in/out over a small period of time. The second method is identical, but uses a dithering effect (also referred sometimes as screendoor transparency) instead of doing a potentially expensive state change. Based on some benchmarks, blending usually looks superior and in many scenes (especially with MOP), the difference in performance is negligible. Supporting either method is quite trivial, however, as these effects will all be done in our shaders to begin with (results will be posted in follow-up MR).
This feature can also replace the hack we have in place for actor fade.
The fade itself should not bring any significant draw or cull overhead, thus there is no need for it to be behind a setting. Abrupt changes of visibility are quite jarring and should be a built-in engine feature. The exception is type of fade, which should ideally be configurable between the blended and dithering technique.
Additionally, LODs should crossfade instead of abruptly changing.
I've also added the 0.49 label, but depending on when I land the MR and where 0.48 is at the time, I think it could be pushed forward to 0.48.