Thanks i copied the default Mat_TheIslandWithMasks_Inst and renamed it to Mat_TheIslandWithMasks_Inst_UK (didn’t want to edit the default one) told my terrain to use this new one, edited the waterline value, default is 100 i made this a negative value and i dont see any differences even with huge value like -1000 or greater, are negatives accepted ?
EDIT: default value is 100 if i raise then i see changes, if i make it 0 i see changes, anything negative seems to sit just at the same position as zero. looks like i may have to height offset the height map i was using to recreate the terrain.