Can Hydrax be used to simulate flowing rivers?

Or is it just for large relatively flat bodies of water?

No, just for large bodies of water like oceans.

Will it then support rivers, some day ?

Unlikely. For that you would need to simulate the water using nvidia physx hardware fluids, On like 4 295GTX's in sli. Even then the river would have to be small.

Scratchy

Unlikely. For that you would need to simulate the water using nvidia physx hardware fluids, On like 4 295GTX's in sli. Even then the river would have to be small.

Scratchy

Is that a joke? Why do you have to use physx fluids? 4 GTX cards in sli mode?

Well he said, "to simulate flowing rivers", And the only current way to simulate water is through fluid in a physics engine. The physx engine is the highest performer, and even more so due to its cuda support. However, While fluids do work, Currently our hardware is not such that it can simulate more than a small amount of it, at reasonable speed.

Cheers

Scratchy

Im new to Ogre but the support for rivers shouldn't be that hard.
I would assume, all you need to do is either modify your terrain so that the water plane would follow through a designed pattern (IE river, creek) that connects with the larger body of water... If you have one.
Or have an additional object (cube, multiple?) and allow Hydrax to be applied to objects and not create just a plane.

Then all you have to do is add a scripted field within the river to add impulse power in the direction of the river.

As long as you have a physics enable object in the water, the impulse addition to its movement would simulate a current.

Yes, That would work but then:
1. Its not really simulated.
2. It would be a lot of work and time in editors getting water paths just right.

Cheers

Scratchy

Yes, That would work but then:
1. Its not really simulated.


That depends on your definition of a simulation. Every game could be considered a "simulation" to some degree, even the original Space Invaders is a simulation of space ships.. yet it's not much more than a couple of sprites.

Does Hydrax simulate water? Yes, but that doesn't mean it follows the laws of physics. The point being, if you can produce a believable river flowing effect, it is a simulation.

Games have been using tricks to create the illusion of simulating things since the dawn of time.

Well hydrax, Is awesome, But i would not class it as a simulation.In my mind, a simulation is something, Which imitates another thing in every way.

Cheers

Scratchy

Well hydrax, Is awesome, But i would not class it as a simulation.In my mind, a simulation is something, Which imitates another thing in every way.

Cheers

Scratchy

Well, I may be wrong, if so please correct me. SIMULATION in terms of Real Time Rendering means faking the real implementation in a much simpler way to reach a visually acceptable but not perfect outcome.

So, scratchyrice:
I see that what you understand from simulation is the real dictionary meaning of simulation, which virtually can not be achieved in real time even with the most powerful supercomputers
In Realtime rendering, any visualization that is close to real thing (an outcome with acceptable minor flaws) is assumed to be the simulation. So if you can make something that fakes the appearance of flowing rivers, that is simulation even though the objects you put on its surface do not move with it, even though the objects do not levitate on it, what we call simulation here is the visual clone of the original thing

It is very much possible with current hardware, but the implementation is somewhat scene specific and hard to generalize as with the case of shadows. There is an article describing it (even with waterfall support) in GPU Gems Series...

ismail,

I see that what you understand from simulation is the real dictionary meaning of simulation, which virtually can not be achieved in real time even with the most powerful supercomputers
In Realtime rendering, any visualization that is close to real thing (an outcome with acceptable minor flaws) is assumed to be the simulation. So if you can make something that fakes the appearance of flowing rivers, that is simulation even though the objects you put on its surface do not move with it, even though the objects do not levitate on it, what we call simulation here is the visual clone of the original thing

It is very much possible with current hardware, but the implementation is somewhat scene specific and hard to generalize as with the case of shadows. There is an article describing it (even with waterfall support) in GPU Gems Series...

ismail,
Agreed. I just think tho, That because the sea is a a large body of water, A Hydrax type system works very well for it, As there are no accurate borders, or gradients like there would have to be in rivers. I've seen river implementations in crysis etc, And it just doesn't work as well as it does in the sea

Cheers

Scratchy

You might be interested in this...

http://www.gamedev.net/community/forums ... _id=526062

It's a lot more suited to what you are after than Hydrax (at least as of 0.4).

Sorry I failed to clarify my original quesiton.

I did not, in fact, want to simulate fluid dynamics.

What Hydrax does, as far as I can tell with my limited knowledge, is visually model a water plane.

I would like to visually model the surface of a flowing river that moves from higher elevations to lower ones. I am not interested in the physics of water motion, but rather the appearance.

I do think, at this stage, that Hydrax would be unsuitable for what I have in mind.

I am looking for a tool that will add fairly realistic rivers/streams to an Ogre terrain. Any suggestions?

Why don't you just use particles ?

You might be interested in this...

http://www.gamedev.net/community/forums ... _id=526062

It's a lot more suited to what you are after than Hydrax (at least as of 0.4).

I agree hydrax is trying to solve sea rendering (probably can do lake as well). A separate plug-in for simulating river geometry would be better. That example is actually quite interesting