so for a large sim your voxel size would stay the same and your count larger. if you wanted it to behave simmilar in a large environment. I dont know your level of understanding with fluid dynamics, so I dont want to come off the wrong way. But a way to describe voxels in space. say your in your room at home. that room has square feet cubed that make up the volume of the room. each in this case is a voxel. so your room is maybe 10 by 10 feet just to make the math easy. so your room would have 100 voxels total that fill the room, saying you wanted each voxel to be 1 foot squared. ok with that in mind lets think a room 8 times the size in order to maintain the fluids effect you would have to increase the voxel count, not their independent voxel size. So size 8 times. x= 128 x 8 y=128 x 8 and z = 128 x 8. Back when I used realflow there was this whole thing on pouring a cup of water out. And setting its relative size to a human. So when you were pouring out the water it could spill out like an ocean or a cup of water. this all has to do with voxel size.