The VoxelTerrain DLL re-enables some hidden constants in the WorldClass script class.
These are documented below.

WorldClass Constants

• World.renderMode (string)
  Sets the render mode of the world.
  By default, only "outdoor", "challenge" and "warehouse" are available.
  However, there is a hidden extra mode - as this mode removes the sun/skybox,
  the assumption is that it is intended for an underground cave world,
  so the VoxelTerrain DLL exposes this mode as "underground".

• World.enableVoxelTerrain (boolean)
  Sets whether voxel terrain features are enabled for this world or not.
  This decides whether or not the terrain script callback to generate terrain chunks is
  called and also affects the functionality of the various voxel spawning functions.
  This defaults to true.

• World.voxelMaterialSet (string)
  Sets the file path to the ground material set to be used by the voxel terrain.
  Defaults to "$CONTENT_1cf785ff-18e3-40f9-89b5-d7816bf835f4/VoxelMeshes/Materials/voxel_materialset_standard.json" (VoxelTerrain Helper mod).
  If the helper mod is not available, it will instead default to a very obvious error material.

warning

World.enableVoxelTerrain is incompatible with World.isStatic and World.isIndoor!
To use voxel terrain, both World.isStatic and World.isIndoor must be false.
If voxel terrain is enabled together with either one of these, voxel terrain features may
not function properly and a warning message will be logged to the developer console.
This was necessary to avoid some technical issues in the voxel terrain implementation.