Subchunks

All the actual blocks in a given buildplate are stored in the subchunks. Each subchunk is 16x16x16 blocks.

Subchunks contain 3 json tags: block_palette blocks position These are explained below.

block_palette

the block_palette tag contains a key of all the block types used in the subchunk and their datavalues. It also defines the ID each block holds for that subchunk and this is important for the blocks tag. An example block_palette entry is below:

{"data":0,"name":"minecraft:sandstone"}

blocks

the blocks tag is simply a list of integers. Each integer corresponds to an entry on the block_palette as stated above. Due to every subchunk being a fixed size regardless of the actual size of the buildplate, this means that no actual block coordinates are necessary.

position

position is the simplest tag in the subchunk. the subchunk's position tag defines where it fits in compared to the other subchunks in the buildplate.