I’ve been running some fire simulations for maybe 5 hours now, and just recently my simulation started falling apart after 30 frames - when i turned down the ‘reaction speed’ it fell apart after 22 frames.
I see a few things that could be problematic here.
1-The cache type is set to replay. Replay is only a viewport/preview thing and it doesn’t bake a good, permanent cache. If you are baking the simulation for hours, you should set it to modular instead. This will allow you to bake the base simulation and the noise separately, so you can see if the simulation is behaving before commiting to baking the noise.
2-You have an initial velocity of 10m per second, plus it looks like some wind fields. If the scene has the correct scale, your smoke is set to be blasted upwards at a huge speed. A fire simulation will usually rise by itself thanks to the “buoyancy density” and “buoyancy heat” settings, so it should not need to be pushed artificially like that.
4-Make sure there isn’t any turbulence field with crazy settings somewhere in the scene.
3-If there are still problems, try to turn down the 2 vorticity settings (in the “gas” and “fire” tabs), they can cause that kind of effect if they are too high.
I use the replay as a preview and then bake it under the ‘all’ setting
But thank you so much man!
I turned down the wind fields from 8 to 3 and it works perfectly now! Without the wind fields the fire doesn’t rise in a straight line once it leaves the window area… so I cranked them up and forgot about it! much appreciated for the help!
