Turbulence not working in new Phoenix versions

[LudvikKoutny]

Hi

I've been doing a job with Phoenix some months ago and now I have to do a few fixes, but I was lucky enough to get all those shots done in the version that had the bug causing icon scale to affect forces. Now, with new version, for some reason, I can't get my grid to react to turbulence force no matter what I try, even if I create a new force. I tried reverting to official non nightly version, but even the official one was updated to January 10 version, where the bug is fixed.

Right now, none of my sims match the old ones, and when I try to tweak turbulence parameters to match the old setup, it seems to have no effect on the grid whatsoever. Even if i crank up strength or scale to crazy high numbers.

[LudvikKoutny]

So little update:

All scenes that I've done in 3.00.01 are broken in 3.00.02 as well as latest nightly. The sim turns out completely different and quite ugly looking. Client requested some changes, and I have a hard time complying, since there's not even 3.00.01 available for download to get back to, even if I check "Show older versions", which just shows 2.20.00 installers.

[lander]

I still have the 3.00.01 installer on drive. What's your mail and I'll transfer it to you. (that's ok right. not breaking any license agreements)

[LudvikKoutny]

I still have the 3.00.01 installer on drive. What's your mail and I'll transfer it to you. (that's ok right. not breaking any license agreements)

Oh, hey! Thanks so much!

it's rawalanche [at] gmail.com

[Svetlin.Nikolov]

Hey, a nightly from the next few days after Sept 9 should do the trick as well. You should be able to see those here https://nightlies.chaosgroup.com/main#/phoenix3max

Would it be possible to send the scene over to Support@chaosgroup.com so we can track what's changed and make it work?

Thanks!

[LudvikKoutny]

Hey, a nightly from the next few days after Sept 9 should do the trick as well. You should be able to see those here https://nightlies.chaosgroup.com/main#/phoenix3max

Would it be possible to send the scene over to Support@chaosgroup.com so we can track what's changed and make it work?

Thanks!

Yes, absolutely! Will send you a scene along with description and pictures within an hour. Thanks!

[LudvikKoutny]

Scene sent

[LudvikKoutny]

I got reply from support that they are overloaded at the moment. I hope the scene will find you eventually

[Svetlin.Nikolov]

Ouch, I hope these next few days..

[Svetlin.Nikolov]

Hey,

Got the scene finally.

The reason why you get a very big difference in particle numbers is that you use open geometry in Volume Inject mode. A fix from Sept 28 for a different issue had changed the behavior of open objects, but the scene had worked only by chance until then - you really shouldn't be able to emit anything in volume brush or volume inject if the emitter geometry has no volume. It's a general rule never to use open geometries with Phoenix. We need to add a check that will warn you about such geometries, but it will slow the simulation down and we're still looking for a way to do this check fast.

The issue is not related to the turbulence, but its effect is a lot weaker. The turbulence affects the smoke and temperature channels in the fire/smoke simulator by default. In 3.00.01 the opened surface produced an erroneous volume that emitted more temperature, while in the new builds this volume is not present, so the temperature is a lot lower. You could either increase the temperature of the source, or you could add 'velocity' to the channel list of the turbulence, but for this you need to be on a very latest nightly. Since drag particles are carried by the velocity field, this would affect them directly and won't depend on how hot the surrounding voxels are.

To get closer to the results you had, you should also:
- close the geometry's back end
- switch to Surface Force mode
- increase the outgoing velocity a bit, to match the volume inject effect

I hope this helps - it would be way easier to use 3.00.01 to make the required fixes, but in the future you should watch out for open geometries, because they can cause such issues with the side effects they produce.

Cheers!