Knuckle Cracker Wiki

Sets the override height of the terrain cell at X,Y. Unlike SetTerrain, the override height of the terrain can be set above 10. This can be used to contain large amounts of creeper and prevent it from overflowing. This is how the creeper is contained in the Credits mission.

Terraforming with Terps will not change the override value of the cell. Recommend not allowing Terps on maps when using this feature.

Virgil also mentioned not using mass drivers. Not sure what that is or how it affects terrain.

# Create a 200 height virtual box around cell 5,5
# An emitter at 5,5 will create a column of creeper, and will
# not overflow unless its strength is greater than 200.
9 2 do
	I 2 200 SetTerrainOverride
	I 8 200 SetTerrainOverride
loop
9 2 do
	2 I 200 SetTerrainOverride
	8 I 200 SetTerrainOverride
loop