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Prefabs is a Volume of blocks meant to represented prefabricated areas within the world. You can save bits of the world, re-load them later, and include them with your mod.

They can also be used to clone sections of the world easily.


You can find documentation here


In case you want to create/use an external program that takes advantage of prefabs, here is the binary spec for the .pfb format:


Name Type Bytes Notes
Magic Length byte 1 The length of the magic header string (val: 6)
Magic char n The characters for the magic. Should always be "PREFAB"
Version byte 1 The version number. Currently 0
Width signed int32 4
Length signed int32 4
Height signed int32 4
CenterX signed int32 4
CenterY signed int32 4
CenterZ signed int 32 4
Blocks[] ushort array 2 * width * length * height The array of blocks. Coordinate determined by: z*width*length + y*width + x