Level Of Detail if I recall correctly (so stuff further away has less LOD, while stuff closer has more LOD). but I maybe be thinking something else
yeah, it's Level of Detail. Basically, a block can pass as a ball if it's far enough that you can't tell the difference. The farther the object is from you, the less detailed it gets. This saves resources and improves performance.
The land near you can be bumpy, but the lands far away are really just a sheet of paper with blocky stuff added in