Fluid Physics extension?

So, the Phizix extension is pretty darn awesome, but as it's a rigid body physics engine, it can't simulate fluids like water (I ASSUME, STOP READING NOW AND CORRECT ME IF I'M TALKING NONSENSE [/caps]). I haven't actually tried to see if this can be done with it, I haven't really gotten to grips enough with it to start that kind of experimenting.

SO, I'm just gonna steam ahead with this post in the knowledge that I might be ENTIRELY WRONG ;D

Yeah, so I was thinking it would be really cool if there was a non-solid physics extension, to simulate fluids in a side-on and/or top-down 2D plane. I don't really mean the whole ultra-real job, with droplets from splashes being rendered, but some neat things like rippling when the surface of the fluid is broken, and objects floating on or in the fluid being pushed aroud by the ripples.

I'm not sure whether this would be even possible, so this is more of a "would this work" thread, and discussion thereafter, rather than a request.

Your thoughts? :)

that would be very cool, but i think it´s very hard to programm
and it would be hard for the processor.

You could just program that yourself, I mean, it's not that hard.

I think Werbad has a file with something like this... Ask him :)

doing the actual *physics* behind it is ridiculously hard and frankly impossible for any processor on the planet, since you are needing to model the interactions on a molecular level, on how water flows. However some tricks exist, like if you have your water bounded into an area, and has no chance of pouring out, you can treat it as a solid object, and only model the SURFACE. Just modeling wave patterns is fairly easy.

But if you want something where you can pour water, you're out of luck.

Box2D has something called a buoyancy controller that currently is work in progress. Demo
But I assume you want interactive waves and stuff as well. I don't know how to do stuff like that at the moment...
I have a simple wave example though, but it's just waves and no way to implement any physical interactions with them.

Quote:

---

Originally Posted by MechaBowser

You could just program that yourself, I mean, it's not that hard.

---

I know nothing of coding in a language xP

Quote:

---

Originally Posted by Pixelthief

doing the actual *physics* behind it is ridiculously hard and frankly impossible for any processor on the planet, since you are needing to model the interactions on a molecular level, on how water flows. However some tricks exist, like if you have your water bounded into an area, and has no chance of pouring out, you can treat it as a solid object, and only model the SURFACE. Just modeling wave patterns is fairly easy.

But if you want something where you can pour water, you're out of luck.

---

Yeah, I wasn't thinking on that kind of lines, I just meant something that can ripple when something hits it, not pouring physics or anything complex along those lines. I guess what I was thinking is more an extra on the current Phizix engine, or something along those lines. So, you could have a pool of bounded water, and drop a box in it. The water would ripple in reaction, the box would sink or float according to it's buoyancy (probably something to be set under the extension's properties in it's actions, again like Phizix's weight/torque etc). If something else was dropped in, the pushes of the water would affect the first box. For example, if it was floating, the ripples from the second box might make the first one be pushed towards the side a little, and bob around a little on the ripples or waves or whatever. A constant current on the water would push objects around, too. Heavier objects obviously wouldn't be as easily pushed around as light ones.

Uh, I hope that's clearer. I'm not sure it is, but I'm not entirely sure how to describe it xP

EDIT: I should point out that this isn't an extension I need, or am requesting. I was just messing around with Phizix and thought it would make a pretty neat extension. I was just curious as to what everyone else thought, and whether it would be even possible. Curiosity gets the better of me =]

http://www.create-games.com/download.asp?id=7298
I don't know about extensions for it, but I did bouyancy manually in my physics engine >.>
No idea on the waves, thats not my boat, so to speak

Quote:

---

Originally Posted by Werbad

Box2D has something called a buoyancy controller that currently is work in progress. Demo
But I assume you want interactive waves and stuff as well. I don't know how to do stuff like that at the moment...
I have a simple wave example though, but it's just waves and no way to implement any physical interactions with them.

---

Speaking of that is there any time extimate on the extension you said you'd make for it?

Not at the moment... I'm working on a new interface for it, and I'd rather wait for the next version before I continue since it has some features that I really want. That and the fact that I have to reverse engineer the entire engine to break out some global variables and make them accessible from the extension properties...

If you just need ripples in the water then you could simulate a water's surface with the Phizix extension using many rectangles with joints inbetween them. If you take a look at the included examples of bridges, they act sort of like waves. If you were to make the links smaller and add more joints it might look convincing.

Quote:

---

Originally Posted by netninja

If you just need ripples in the water then you could simulate a water's surface with the Phizix extension using many rectangles with joints inbetween them. If you take a look at the included examples of bridges, they act sort of like waves. If you were to make the links smaller and add more joints it might look convincing.

---

except it'd lag like hell :V

If you look at the file archieves from way back, there actually IS a water effect tutorial around with waves, and it uses the Overlay object.

Soft body dynamics (I think liquids belong to this) are very complex if they're supposed to be REAL. Of course, you can't do it that realistic at realtime, but seriously, animation companies like pixar work ages (multiple years) on algorithms for that. I think there are some decent engines for this, but I'm afraid that MMF might be too slow to handle it - Not too sure.

i guess a really crude version could be done in a way similar to the falling sand games, which would give you some ability to have flowing liquids, though it'd take more work getting surface effects to work like real water, and the code would need to be optimized into the ground to keep it from hogging your CPU