Fire sim idling after a while

[james_bonham]

I have a really simple fire sim based on the default fire sim tool. The sim is running nicely but after a while it just stops and doesen't progress at all.

I'm using the latest version with Max22, still have like 100+ GB free memory, etc. Decreasing/increasing the resolution isn't helping either but once again, the sim is simple and the PC is more than capable to handle this. I had no problems with water sims at all, even when those are running for hours, my PC is happy with everything but this fire sim stops after like 3 mins. I can't even stop/restart if with the designated toolbar buttons, Max is just unresponsive after I try to use those.
Anyone had something similar in the past?

[georgi.zhekov]

Hey,

Doesn't ring any bells. Is there any warning or an error in the Phoenix log? You can find it at C:\ChaosPhoenix

[james_bonham]

oh well, I have to admit, I didn't even know about the log:

Chaos Phoenix 5 ADV for 3ds Max 2022 / V-Ray 6.x,
version 5.10.00, Build ID: 20230420 from Apr 20 2023

Log Started on 2023.05.12, 11:04
Windows version: 6.2
Platform: x64
Memory info: Total: 127.875 GB; Free: 117.484 GB

Loaded c:\programdata\autodesk\applicationplugins\phoenix 3dsmax2022\plugins\distance_measurer_phx.dll
#BaseObjMax::updateNodeVersion() - file version 62 created with buildID 20220706
PhoenixFDFire001 startSim
Grid set to 106 x 400 x 42, 1780800 voxels, memory usage 0.100GB
Sim started
output: C:\[***]\fire bowl 003.max_Phoenix_frames\PhoenixFDFire001_####.aur
Sim step 0, sim time:0.000000, last frame:0.000000, elapsed: 0.000000
export frame 0 fill: 0.197267 <----------------------------- FRAME: 1/181 (0.55%)

.
.
.

Sim step 54, sim time:1.800000, last frame:3.421489, elapsed: 180.278776
export frame 54 fill: 0.077524 <----------------------------- FRAME: 55/181 (30.39%)

Sim step 55, sim time:1.833333, last frame:3.089858, elapsed: 183.328205
[ERROR] PhxArray setSize() with a negative newsz!
[ERROR] encode rates failed!
export frame 55 fill: 0.078327 <----------------------------- FRAME: 56/181 (30.94%)
[ERROR] decodeAndExpand - constant sequence longer than expected

Sim step 56, sim time:1.866667, last frame:3.017910, elapsed: 186.327747
[ERROR] PhxArray setSize() with a negative newsz!
[ERROR] encode rates failed!
export frame 56 fill: 0.080229 <----------------------------- FRAME: 57/181 (31.49%)
[ERROR] decodeAndExpand - constant sequence longer than expected

.
.
.

Sim step 85, sim time:2.833333, last frame:3.072227, elapsed: 278.014792
[ERROR] PhxArray setSize() with a negative newsz!
[ERROR] encode rates failed!
export frame 85 fill: 0.076599 <----------------------------- FRAME: 86/181 (47.51%)
[ERROR] decodeAndExpand - constant sequence longer than expected

Sim step 86, sim time:2.866667, last frame:3.041745, elapsed: 281.023757
[ERROR] PhxArray setSize() with a negative newsz!
[ERROR] encode rates failed!
export frame 86 fill: 0.079514 <----------------------------- FRAME: 87/181 (48.07%)
[ERROR] decodeAndExpand - constant sequence longer than expected

Sim step 87, sim time:2.900000, last frame:3.034523, elapsed: 284.108396
[ERROR] PhxArray setSize() with a negative newsz!
[ERROR] encode rates failed!
export frame 87 fill: 0.078760 <----------------------------- FRAME: 88/181 (48.62%)
[ERROR] decodeAndExpand - constant sequence longer than expected


And this is where it completly stops and start idling. When I press stop on the toolbar, my Max freezes and I have to close it with the task manager.

[Svetlin.Nikolov]

Hmmm, so far we've had a few reports about issues on 128 gig machines and unfortunately every time it turns out to be a bad RAM stick.

It's also strange that this didn't happen with the liquid simulations. Could it be related to the GPU Preview - what if you turn it off?

[james_bonham]

Sorry for the late answer, this project is not main prio atm...
Turning off the GPU preview did nothing.
I switched the preallocate memory to `always` and that helped with the errors msg, now the sim runs to frame 88 without any issues but still stops there, so it's pretty much the same.
I'm not in the office now and that makes it harder to test the RAMs, but it looks like it that will be the issue... I started the sim at home on another PC and it can finish the sim easily without any problems, so the scene should be fine.
I will get back to you next week.