valheim terrain fix console command patch 0.150.3
this is the command to fix existing terrain using the new system introduced in patch 0.150.3
enable the console, starting the game with -console
to add the -console to your valheim, in steam right click the game and select properties
then in the next screen add -console into launch options
console can now be accessed in game by pressing F5
then once you are in game you can open the console, and type in optterrain
which should fix surrounding terrain with the new system.