Main functions:
Easy to set up (just read the setting instructions)
Digging/adding Mater on the terrain
Paint textures on cave meshes
Automatic collision solver
Automatically create detail level groups
Support multiple terrains
Use Unity 2019.3 and higher: fully support navigation grid
Compatible with Gaia
Only applicable to Digger PRO: real-time mining at runtime.
Exclusive to Digger Pro: Update NavMesh at runtime.
