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Comment by th0ma5 | Hacker News Reader

I know it is often the topic of SIGGRAPH demos, but I always get distracted now when game or demo physics don't go the extra mile in calculating all of the factors, or having realistic drag (and things like that)...

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What would be the advantage of highly realistic physics though? In some cases it would improve gameplay (I remember the Newtonian physics in the Independence War games resulted in relatively novel gameplay) but in a lot of cases I don't think it would. Minecraft especially is kind of abstract, and it already struggles a bit with performance on some larger multiplayer games. Super realistic physics would just make this worse and not add that much to the gameplay, IMHO.

Well, yes I can see in games it being just eye candy maybe, but even in incredibly flashy renderings (like heck even Target commercials) there's just sort of a basic Verlet integration of speed and acceleration or deceleration but not many things like air drag, friction on the surfaces, little "oops" that happen with uneven surfaces and random errors in trajectories, etc... I have seen SIGGRAPH white papers that contain a lot of these sorts of things and more as a group, and well, lets hope those eventually get read and used. The current state of the art reminds me of when I first learned Photoshop and I couldn't stand any magazine covers I saw (actually I guess I still can't heheheh)

Target commercials aren't really a fair comparison to Minecraft. One is the work of a team backed by large company and gets rendered once on powerful hardware (I think... I don't know what you're specifically referring to but I assume it's some computer animated spot) and the other was largely the work of one programmer and has to run on cheap PCs and Macbooks (sure it doesn't have to but I would argue that's part of Minecraft's success: you don't need a gaming rig to play it, as you do to play something like Skyrim).

I definitely understand where you're coming from but keep in mind that you likely have a much deeper understanding of physics than most game players (and likely most game devs).

Minecraft does have terminal velocity, though (it's obvious from the very first shot showing the pole while falling), therefore it does have some implementation of air resistance. So as soon as the video says "assuming air resistance to be negligible," it's oversimplifying, as Minecraft clearly does not have negligible air resistance.

I'm similar. I'm playing a lot of Terraria recently, and it bugs me that you can have a tower of water in a tube connected to a shallow lake, and the pressure doesn't force the water through.

That bugs me too. I have started a small project to make a more realistic water simulation, and found it to be quite a bit more involved than I had expected. Just adding pressure would fix the problem you mentioned, and would probably be pretty easy to do. Adding velocity so that the water sloshes properly seems to be the hard part.

fluid dynamics is anything but easy. current sandbox games (minecraft, dwarf fortress, terraria) implement water flows as cellular state machines. this is clearly wrong, because pressure is non-local, but computational expense of doing water correctly is prohibitive.

> current sandbox games (minecraft, dwarf fortress, terraria) implement water flows as cellular state machines. this is clearly wrong, because pressure is non-local

Dwarf Fortress's algorithm actually supports global pressure propagation, albeit in an ad-hoc fashion:

http://www.gamasutra.com/view/feature/3549/interview_the_mak...

There are some mods that try this. Finite Liquid (http://www.youtube.com/watch?v=XlnUXXzc1Fg) for Minecraft, for example, implements a simple pressure system, along with pipes, pumps and other flow/flow-control tools.

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