Strange sim results from splash and foam in nightly builds

[andrezaguayo]

Hello all, I have this strangeness going on with my splash and foam in the nightly builds.(The Liquid seems to working great) The foam is creating some strange grid pattern. Not sure exactly sure how all the new parameters are working with foam and splash, but I tried to keep it all the same as I was doing before. Does any one know why my partials could be not simming properly? I am thinking this is a user error on my part, but not sure. Thank you everyone. I have attached some images if what it is looking like. (The White objects are just simplified sim objects of huge boats)

[Ivaylo Katev]

that's a new one, it's not an user error for sure, seems like the preview auto reduction affects the render, but this is impossible, must be something else similar to it. can you share the viewport but with disabled auto reduction?

[Ivaylo Katev]

i think i know what is it. for some reason you have one or more splash particles far away, this is a bug for sure, but you can workaround it. the reason for the particle ordering is the particle compression. the compressor automatically increases the dynamics in order to catch all the values existing in the data, and the far particle disturbs this process, leading to the result you have. so, just disable the particle compression (output panel), also i would like to have the scene, to investigate the problem.

[andrezaguayo]

I think disabling the particle compression is working. Thanks! I have uploaded the file for you to dropbox to check out. I tried to strip out all the crap so it is easy to understand, you will notice 8 other Phoenix sim objects that are in there for the other ships. I left them in there encase they are effecting the main sim on the front two boats, but are not related.

https://www.dropbox.com/s/bmx8qqszgk...lo_AA.max?dl=0

[andrezaguayo]

Hey Ivaylo, I am having great success with disabling the "particle compression particles" all is working normally and the sim is looking pretty good. Now I am having a pretty annoying issue when trying to render it, I keep getting this error message. "UNHANDLED EXCEPTION: Render region... Last marker is at ./scr/globillummap.ccp" and then it crashes. I have GI off so I don't know why this issue is coming up? Any ideas? Was never having this issue before. Attached an image of the error. I am thinking it might have to do with how many particles I have, because it renders fine in early frames, but starts to get flaky when there are a lot. Here are my numbers, is it to high? Liquid 7m, Foam 176k, and Splashes 39k mist 0.

By the way I can't thank you enough for all the support I truly appreciate it.

[Ivaylo Katev]

can you attach the phoenix log file ? it's placed in c:\phoenixfd folder.
i suppose the particles that cause the compression failure may be involved

[Ivaylo Katev]

today is not my day, after investigating the problem few hours, i released that your simulation is not using the flip core, it's based on the old core. see the advection method, it's classic, must be particle based (flip ). beside this the storage quality is too low, the default value is 14 , 8 is not enough for the particles.

[andrezaguayo]

Shoot! I thought I responded to this already must not of posted properly, sorry.... anyways thank you thank you thank you for spending hours of your time this. I seriously appreciate you time and effort in helping. You are awesome.

After reading your recommendations, so far I have not noticed any random crashes when I render. I think the problem arises only when I try to render a sim on that used the classic advection method. It could be from raising the storage quality back to 14 as well. But it is working. Let me know if you still want the Phoenix Log files?

[Ivaylo Katev]

if you have log file with a crash, yes i want it

[andrezaguayo]

I have not had the crash on a render since Tuesday, and not sure how this log thing works but here is the file that is in my c:\phoenixfd folder.

https://www.dropbox.com/s/6lc50pkz8h...ver17.log?dl=0

[andrezaguayo]

EDIT: I think I fixed my problem I dropped my By Free Fly level and increased the Splash Multiplier. Now it is not generating particles in the middle because the Free Fly level is low.

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Ok,I hate to say it but, I have one more question/error Sorry

I was getting solid results with one ship, now I have extended the area to include both boats and am having another strange behavior with the splash and foam. Between the two boats, where there is a lot of water not doing much, I am getting a bunch of random particles being generated. I thought at first it was an artifact of low render settings, but no in fact it is particles being generated. Check out this video to see what I am talking about(https://www.dropbox.com/s/gu6lndgyff...Boats.mov?dl=0). I am thinking maybe it is related to the threshold of the splash particles, but I am still not fully understanding the new parameters quite yet compared to the Rate and Threshold before. Now it is By Free Fly and Splash Multiplier are those the same as before with different names or how is this by free fly working? Still even if the threshold is to low and it is generating partials in the middle area where there is not much movement it should not be flickering. Any idea on what is going on with this?

[Ivaylo Katev]

first you have to determine the type of the particles, splash or foam.
let me explain more about the birth conditions and you can make better decisions
seeing the image this may be direct foam birth, but is not quite probably. the direct foam birth in the flip core is changed, the old core detects cavities in the liquid, if there is a natural bubble, then we can add artificial bubbles, the bad thing is that this produces bursts of particles concentrated in small area, so we decided to change it. in the flip core the foam is born just bu turbulent dynamics of the water. the parameter that determines the turbulence threshold has units of velocity, if this parameter is too low, you can get foam in still areas.
the most probably is to be splash born by "free fly". this is a new option, the splash is like before born by sharp liquid edges, but beside this you can produce splash when the water is in free falling/flying state. the surface of the water is not in free falling state, if this is the case, it may be a bug in the algo calculating the free fly condition.
my suggestion is to set "by free fly" to zero and simulate again, to determine the reason for the particle birth.

[Ivaylo Katev]

btw, i have the ship scene reworked for flip core, you can see it and compare with your settings. of course i'm still worried about the wrong part in your scene, because our goal is to make impossible this to happen

btw, in the scene folder you will find subfolder called settings and inside it there are two subfolders with simulation and render logs. the simulation subfolder contains log files with the settings of each simulation of this scene, please send me the recent simulation log file , the one with newest date.

[andrezaguayo]

Thank you so much. Sorry on the delayed response. I have overcome as I mentioned that flickering problem with the particles by Turing off the "By Free Fly" from your suggestion. I have attached a dropbox link anyway to that file and the settings folder I was having trouble with so you can investigate that particular problem if you would like.
https://www.dropbox.com/sh/gulkz2sd3...bsbHe3XSa?dl=0

Thank you for the re-worked scene it has been very useful!! Awesome!!

I am still getting a lot of crashes when I try to render more then one sim in a scene. Here is the Vray render error that I keep getting, any clue on what could be happening? "[V-Ray] UNHANDLED EXCEPTION: Rendering region (1872,672)-(1896,696) Last marker is at ./src/globillummap.cpp, line 1692: GlobalIllumMap::buildLightMap() {1} "
I suspect that I am pushing the computer to much and it is crashing, but I am not sure, this error was not happening before the nightly builds and had 10 phoenix caches in one scene and now I cant do more then one with out getting this error.

[Ivaylo Katev]

no, it's not pushing the comp too much, it's a bug, we caught one for sure, related to vrayvolumegrid, a new vray component that is actually the phoenix volume shader, and because it's closely related to phoenix it was causing crashes when rendering foam.
so, my recommendation is to update your vray, if the crashes persist keep a log file after a crash and send it to us.