I've created an Infinite Voxel World, similar to Minecraft

Great job John! Could you do me a favour to answer a few questions:
1、By handle the polygons manually, how do you render the same texture faces in one drawcall?
2、Does a chunkobject handles it’s own blocks, and a chunk manager spawns chunks?
3、Is a block an actor or a meshcomponent attached to a chunk?
4、How do you controls the polygons’s visibilities?