Hi,
I am sorry if I post it in the wrong section as this seemed the most appropriate to me.
I am doing a study project on distance field shadows vs Shadow mapping and my supervisor thought it best to test the techniques in Unreal Engine…
Why exactly cant the distance field shadows work with movable objects? I supposed that the cost of DF calculation at runtime is too high but shouldn’t the same reason be valid for Ambient Occlusion which is being calculated at runtime using distance fields… ?
Distance fields are actually a bunch of boxes that approximate the geometry in the scene - you can’t use DF with moving objects because it would be too slow to recalculate the volumes that make up the DF every frame.
As for AO, that doesn’t need to be recomputed as far as I know - e.g., it’s not actually changing the distance field at runtime in order to render AO using the DF volumes.
Basically, you’ve got the reasoning almost right, except that the expensive part isn’t sampling the DF at runtime, it’s changing it.