Simulation stopping

[Yannick]

Hi,

I have a scene (attached) that stops after 13 frames (out of 175). I can't figure what is going on.
Fog.zip

I am using:
Phoenix FD for Maya 2015, version 2.2.0 from Aug 16 2014, 06:00:42, revision 24851

Another question, I did a sim with a small scale (grid was like 24*24*10cm), is there an easy way to scale the grid up but keep a similar result? From test a sim with the same parameters but a bigger scale are a lot slower.
I saw on the forum, a mention of a scene scale for max. Is there something similar in Maya?

I am currently trying to create a large scene (about 50*50 meters), and I need to fill it with a storm of smoke/fog. Any tips I should be aware of? My approach (that can be see in the attached scene) is to use a vortex field and a few emitters.


Thanks,

Yannick

[Svetlin.Nikolov]

Hello! We'll have a look at your scene, and regarding raising the resolution while keeping the same shape and behavior - yes, you can do it with a latest nightly using resimulation. Grid Resimulation has undergone major changes and now works faster and gives a better result - closer to the original shape and behavior. The prerequisites are to export velocity in the original simulation and eventually Wavelet, if you want to use wavelet turbulence along with increasing the resolution. One more thing to keep in mind - resimulation works best with sims that were simulated with 1 step per frame. With more steps the hi-res result starts to differ from the low res. One more thing - since you have used an old nightly, run the original simulation one more time, as some thing in the core might have changed since before.

[ivaylo.ivanov]

The scene is using a field, so 1 SPF is not an option, but 20 is really pretty high number. It's definitely the main reason for very slow simulation. I din't reproduce this issue with the last nighly. Can you give it a try?
About the scene scale, I don't quite understand what you want to achieve. Like Svetlin said, if you want higher grid resolution with the same behaviour, we have wavelet turbulence resimulation which can increase the grid resolution 2-3 times. This has nothing to do with the scene units though, which are controlled from the top of the grid section. But your simulation will change if you change them.

[Yannick]

The scene is using a field, so 1 SPF is not an option, but 20 is really pretty high number. It's definitely the main reason for very slow simulation. I din't reproduce this issue with the last nighly. Can you give it a try?
About the scene scale, I don't quite understand what you want to achieve. Like Svetlin said, if you want higher grid resolution with the same behaviour, we have wavelet turbulence resimulation which can increase the grid resolution 2-3 times. This has nothing to do with the scene units though, which are controlled from the top of the grid section. But your simulation will change if you change them.

Hi,

The speed of the simulation isn't the issue I am having. My issue is that the simulation stops after some frames. I can see that Phoenix is still computing, but my smoke is not moving or changing, it just froze.
I did another test last night where I reduce the FPS to 8, this time the sim work up to frame 67 (out of 175).
I tried with a FPS of 2, in order to see if more frame get simulated. Not my simulation goes up to frame 137.
I never encounter this issue previously where the FPS define the amount of frame simulated.

On another note, because my smoke is moving fast, I though I had to have a large FPS value.


Regarding the grid resolution, I did some R&D test with a grid of 24cm*24cm*15cm (about 1.5M Cells). My simulation worked fine and I was happy with the result. Now for my project, I need to work at a bigger scale, 50m*50m*15m (still with 1.5M cells), I was wondering if there is an easy way to scale up my R&D scene to work at my scene scale. Or do I need to rebuild the scene at my project scale?
I understand that element, like gravity will have a different effect on the smoke at large scale, so I am expecting some change on the overall look.

I will see if I can get our IT dept to upgrade to the latest nightly.

Thanks,

Yannick

[Yannick]

Something I completely missed is the Units Scale in the grid menu. This allows me to get the dimension for the simulation. However the Grid it self is small in scene scale.
Can I scale the grid up, through the Maya scale transform tool? Will it still work as expected?

Thanks,

Yannick