ship in the ocean

[TSR_trix]

What was SPF in this one Ivo?

[Ivaylo Katev]

it's two, if i remember correctly. the scene is included in the max nightly build

[jstrob]

Hi Ivaylo! Your xeon E5 2680 is it a dual xeon running at 2.7Ghz? Or is it E5 2680 v2 running at 2.8Ghz? I am now simulating the example with dual xeon E5 2680 v2 and it takes 1 minute 16 sec a frame.

[Ivaylo Katev]

dual xeon v2 2.5 GHz

[jstrob]

dual xeon v2 2.5 GHz

Ok in that case at 2.5 Ghz, it should be a dual xeon E5-2600 v2. and not E5-2680 v2 which is 2.8 Ghz.

anyway just curious to see how different hardware can sompute with phoenixFD. I wonder how fast the faster i7 would be with this scene?

Does anyone has a Intel Core i7-5960X Haswell-E 8-Core 3.0GHz to benchmark this scene?

[Ivaylo Katev]

actually it's 2670 ,my that's why every text on the screen must be copyable
anyway, my observations are that the cpu is not the most important one, the ram speed is the main bottleneck, and for some scenes involving huge particle count (about 50M) the most important is...the HDD speed i'm speaking about the ink in water scene, we observed this effect simulating it on different machines.

[Neilg]

Have you done much tests with ram speed and it's effects? If it's significant and available in a handy comparison i'd be able to use it to get some new ram for our next phoenix job already got an SSD in the sim machine.

[jstrob]

Ok. good to know. I use ssd for system files, but i will buy one for the sim too if it's a noticeable difference.

[Ivaylo Katev]

the hdd is important only in cases of simple particles with very big count, if you have foam or splash the calculation time is too big compared to the hdd time.
for fire and smoke sim the ram speed is the most important, if you have significant foam the cpu is most important

[jstrob]

Now about the ship in the ocean, My sim is completed. But I can't render the phoenixFD athmospheric.

I get UNHANDLED EXCEPTION: Updating athmospheric effects

[jstrob]

I started back from the original file and loaded my cache and now it renders without crash. I may had changed something playing with the file.

You use strange render settings. Fixed image sampler to 3 and global subdivs to 1?

[Ivaylo Katev]

if you have the cache file that causes the crash, we will appreciate to have it for investigation.
about the render settings - compared to the "usual" render settings used for interiors and other fields, they are really strange. the foam and the smoke are volumetric objects and this kills the rendering, we are trying to minimize the rays count. we use ambient light instead real GI, we use directional light or sun with subdiv=1, and other tricks. if you see similar movies made with houdini or naiad, they always use nuke and compositing. this also helps a lot to reduce the render times, but we do not use it, because it involves 3rd part software. the rendering performance is very important, because it is easily exchangeable to quality. if you reduce the render times twice, you can double the particle count. very low count of viewers can recognize the real GI, especially in outdoor scene, but all the viewers can recognize the bigger particle count.
about the image sampler - when you render particles in bubble or splash mode the fixed image sampler has no alternative. the reason is that the adaptive sampler easily can skip a small bubble and will not trace more rays because it seems that there is nothing in this pixel. this causes blinking in animation. i know in the ship scene we use point mode, it may be rendered with adaptive too, but you have to decrease the default settings, otherwise the foam will produce big count of rays, that actually do not contribute to the quality.

[Paul Oblomov]

Vlado promised to look deeper into vray-phx relations

[jstrob]

I'm rendering it right now on my render farm with GI and my usual vray settings. I get 13 minutes with my fastest computer to 28 on my slowest. And it really beautiful! I'll put it on youtube for comparison when my whole animation finished.

And about my crash I discovered it was because I was rendering on a computer on my farm with an older version of phoenix. I installed 2.2.0 rev.24819 everywhere on my farm and no more crash! Sorry about that.

[jstrob]

I took the sample scene in the PhoenixFD sample folder, I simulated it and started with my regular render settings in vray to get better AA.I also turned on GI to see how lojng it would be.

It took around 1 minute a frame to simulate on my new dual Xeon E5-2680 v2 with 64 GB of ram.

It took around 13 minutes to render on my faster computer (dual Xeon E5-2680 v2 with 64 GB of ram) the average frame time on render farm was 26 minutes (mostly dual xeon 2.7 GHZ so it took in all 1 hour and 26 minutes on my farm for 940 frames.

The resuklt of the sim is different from the one published by Chaosgroup. It's because Ii used a different revision. I would have to make my sim box larger cause the foam is getting out on the sides causing straight lines. Also my foam trace is not as long as the chaosgroup result.