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Water simulation

Here is a clip that shows a water simulation I finished a few days ago. I had two reasons for doing this sym; 1. To float an active body on the water which would react to the turbulence and waves. 2. I wanted to see what kind of dynamics I could get beneath the surface of the water; bubbles and foam moving around in the undercurrent.

The shot was rendered with V-ray in Maya. CPU rendering with GI and motion blur. No caustics. The render time varied by the number of particles in the scene (splashes, foam and bubbles) but once the water is in full storm mode, each frame took around 9.4 minutes.

For lighting I used IBL that I may have augmented with one other light but I can't recall...

Nothing fancy but here it is. Enjoy!

 
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Looks great man! I wish I could get that quality of fluid sim in UE. I used to use flipfluids, fumeFX, and stuff like that in max and maya. The fluid sim I'm using now doesn't look nearly as good as this, but it's fast.

I really like the underwater bubbles, that really sells the look of this sim.
 
Phoenix FD for Maya.
When I started learning CGI in the 90s I could only dream of being able to do fluid FX like the stuff available now. The billowing smoke fx are worth the price of of the plug in alone.

I've got another simulation rendering now. Should be ready by morning.
By the way, the V-ray RT rendering is wonderful but not as miraculous as I though, at least not for fluid FX. My original boast of 30 seconds/frame was indeed accurate, but only for shots that didn't have millions of particles right in front of the lens. Those took much longer. .. and I did discover that RT does not support Caustics yet. As for Caustics and CPU rendering, forget it.. I started a batch render that used Caustics then I went out with my wife to do something, when I came back over an hour later my computer was still rendering the 1st image!! I'm no expert on caustics, so I'll keep playing with it to see if I can tune it down for a more reasonable render time. In the meantime, I don't need caustics anyway...
 
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Phoenix FD for Maya.
When I started learning CGI in the 90s I could only dream of being able to do fluid FX like the stuff available now. The billowing explosion fx are worth the price of of the plug in alone.

I've got another simulation rendering now. Should be ready by morning.
By the way, the V-ray RT rendering is wonderful but not as miraculous as I though, at least not for fluid FX. My original boast of 30 seconds/frame was indeed accurate, but only for shots that didn't have millions of particles right in front of the lens. Those took much longer. .. and I did discover that RT does not support Caustics yet. As for Caustics and CPU rendering, forget it.. I started a batch render that used Caustics then I went out with my wife to do something, when I came back over an hour later my computer was still rendering the 1st image!! I'm no expert on caustics, so I'll keep playing with it to see if I can tune it down for a more reasonable render time. In the meantime, I don't need caustics anyway...
True caustics are insanely computationally expensive. Just use real fluid sim and fake caustics, less than one in a hundred can even tell the difference. Caustics will literally add a zero or two to any render time.

When I publish this next video, you can see the fake caustics I'm using. It definitely doesn't look as good, not even close, but it's literally more than a thousand times as fast. Our use cases are quite different though. I'm probably doing a similar number of calculations, but at a very low voxel res over a drastically larger area.
 
True caustics are insanely computationally expensive. Just use real fluid sim and fake caustics, less than one in a hundred can even tell the difference. Caustics will literally add a zero or two to any render time.
Yeah, I was thinking about that. Faking animated caustics makes sense. I think if you project a reasonable caustic pattern from the location of same light source that would otherwise be sending out photons, it could be convincing. I still need to look more into this but I'm thinking this; use a photon map for static caustics like a wine glass sitting on a table, and fake animated caustics like the kind you see at the bottom of a swimming pool... All these years and I wait till now to play with caustics. :)
 
It works pretty well, you can probably find a plugin that will just do it for you on a texture level. The caustics pattern itself is simple refined perlin noise, and you don't notice it much from fixed camera angles. You can improve results if you can distort that overlay on the meta level.

Here's an example of a time I used cheap caustics. It doesn't look great, but this particular video rendered at about 2 seconds per frame in 4k.


Lol, here's how cheap my water was in this early effort, there is no water, I just turned the air blue, turned up the fog, and obstructed the sunlight.
 
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Man, it looks really good! The movement is great! The better texture is in the front, the back looks a little soft like when you add a blur filter in photoshop, the water looks a tad viscous but not by much. Just a little thick for water, only by like 4% (lol)... and the color looks more like a wave pool than any natural body. Hope this helps! Very impressive.
 
Man, it looks really good! The movement is great! The better texture is in the front, the back looks a little soft like when you add a blur filter in photoshop, the water looks a tad viscous but not by much. Just a little thick for water, only by like 4% (lol)... and the color looks more like a wave pool than any natural body. Hope this helps! Very impressive.
Thanks, Indietalk!
Interesting that you mentioned the color of the water. I didn't want to use an ocean shader so, yeah, I was actually going for swimming pool water. I set up the shader myself. That soft blur you mentioned was me not quite understanding all the settings. The test I have rendering right now shows some progress in that area. plus, there's a difference between the way water looks when you're inside it look up to the surface and the way I interpreted it. Real water is a lot like a mirror but I wanted to see what was going on outside the water, so I took some liberties.

Cool video of yours, Nate. Such fast render times, plus your compositions are always very good.
 
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It was all about caustics, and although I got some results, I didn't like them, so I moved on. It just wasn't worth the rendering time, plus it never really fit into my project plans.

Other tests are rendering right now..
 
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