Hello, So I have seen this posted on (last post was early in 2015) but I haven't seen it commented on by devs. Fluid mechanics: they suck. Don't get me wrong, this game is great, which is why I was totally shocked to see water chasing me up the hole I drilled through the center of an island. I get how complicated this issue actually is and, unfortunately, I don't currently have much in the way of suggestions on HOW to remedy it. My initial thoughts on this might help to remedy ONE issue on oceanic/fluid type planets. If planet type is oceanic (I don't think there are oceanic planets without an atmosphere, otherwise, after this check, a check would need to be run to see if the planet has any atmosphere) True: If water at block is pathable to max elevation (or sea level + some amount; top of the world is REALLY high) True: Standard fluid mechanics (non-pressurized) False: Pressurized cavity Easy Option: Stop water rising it's level equals the Y value of the higher side of the opening (higher of the block on the left or right side of the cavity) Hard Option: Do some calculations, taking into effect elevation, gravity, volume of cavity, temperature, and the density of the atmosphere and fluid. You might could make this simpler and just account for elevation and gravity. I'd offer specifics, but I will have to crack open my physics book... False: Standard fluid mechanics Don't know if this is doable since I don't know much about this game's inner-workings yet. Also, it would be less realistic because if a player dove to the bottom of the ocean and dug down, left/right, then up to create a cavity, it would contain no gas and really would fill up with fluid...but anyway... A couple of un-related notes and suggestions. I enjoyed discovering the biome waaaay up high when I was checking to see if there was indeed a max elevation. Props to whoever thought of and implemented that. Any chance you guys could kill weather above a certain height? Maybe include a max cloud layer and above that, no weather? Kinda breaks immersion. I would suggest accounting for gravity and jump height when players get crazy high. This decision really should be by a poll to the playerbase though. Finally, here's a Wikipedia link to the only floating island: https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch. Bottom-line: Islands don't float. Not sure why they do in this game... Sorry if this seems harsh - just trying to help. Thanks again for the great game!