I can't believe I got this to work! One feature missing from Runtime Virtual Textures was that it could not be used to persist data between frames without spawning many planes that rendered to the virtual texture without causing weird artifacts. There is an option in each Runtime Virtual Texture that tells it to not clear before each render which is similar to how Render Targets worked with the additive blending model - but you had the choice to tell it when to clear with Blueprints. This uses some Blueprint tricks (but NO other coding was used like C++). It's probably not that optimsed, but I still get 120 fps my project. Probably best used in small, controllable areas of a game.
