There was a really interesting paper here on HN a few months back, basically if your SDF was data based you could do a low resolution pruning pre-pass over the

There was a really interesting paper here on HN a few months back, basically if your SDF was data based you could do a low resolution pruning pre-pass over the screen and remove the datapoints of the SDF that didn't contribute anything in that screenspace region. Other than that you can actually re-use many simpler SDF's to work as bounding spheres,etc. For example I did a kind of skinned character rendering that kinda started turning expensive and a simple way to accelerate it was to first do a sphere calculation that bounded it, if the sphere calc was producing a large enough value it was output directly instead of the "detail" value of the actual character. Now for a GPU that isn't ideal if one of the "threads" enters the character, but I think most GPU's do triangles one-tile-at-a-time so these threads will most of the time have converging calculations within each tile.