Niagara Cache Results in Different Looking Simulation

[VincentLo]

Hello,

I created a Niagara smoke system in Unreal and decided to cache it. However, the results of the cache differ from the smoke that I had in the Viewport.

The screenshots below should show the differences. The top, which is what I want, shows smoke that hangs off the roof for a longer duration. The bottom is the cached version. It seems like the smoke is being cut off earlier. How thick the smoke is feels different as well.

Here are some gifs that demonstrate the differences as well. I isolated only one of my systems
The system below is playing with the cache.

The system below is playing without the cache. (Sorry for the beginning being cutoff, I’m pressing auto-activate and then rushing to capture a gif.) As you can see from this, the smoke feels more dense and comes down farther.

I have tried the different System Life Cycles and the latest version of Unreal (5.4.3), but the cache still results in unintended results. I also thought it may be a matter of the cache duration, but even with a cache that lasts several hundreds of frames longer, I still get the same issue.

It’s hard to iterate on the look when I can’t expect the cache to look the same. What would cause this and how can I go about fixing this discrepancy?

Thanks in advance.

[elia.misculini]

Hi! I had a similar issue today: I made a rather complex niagara fluid sim to create a cannon explosion, which was fired by a very fast istantaneous Burst emitter. When I get to record the effect into a niagara sim cache, the baked simulation looked way simplified and very different from what I was seeing in viewport. The solution was to set, in the system module, the “fixed delta time” to true. In that way the simulation is framerate independant and the baked and played simulation are the same. Hope it helps!