Have you ever tried to simulate a spray, stream of steam or a fountain in Fusion?
Then you will be interested in further reading!
The most obvious way to create a spray is to set the Angle Variance and Angle Z Variance in the pEmitter >0.
You can even go further and apply a high-frequency Shake to the pEmitter > Region > Size.
Surprisingly, this solution doesn't really make the particle simulation slower... Quite the opposite!
Considering that you need to dramatically increase the pRender's Sub-frame Calculation Accuracy to avoid steppy emission in the normal case.
Nice and elegant, I like it!
Put it in a little macro?
I came to a conclusion, that making macros for particle systems is not too handy in Fusion.
First, you get an annoying message "Particle tools can not be branched" every time you open a comp with such a macro, and second, particles get doubled with a higher probability.
So, better just bare particle tools with "user controls" and "simple expressions".
Thanx for sharing the comp!
I'd go with a pPointFforce next to the emitter. This way it's not necessary to use that large Sub-frame Calculation Accuracy.
I would limit the pForce with a region to avoid it's influence throughout particles' life.
You will need to increase the Accuracy anyway though (see the simulation from the side).
I agree with that. But 3-4 samples is enough.
With the collision it's up to 10 samples because it calculates the bounces exactly on the surface (per samples) while with the force you still have the initial volume of the emitter as a spread.
And yes you have to limit the force indeed.
Well, actually, if a particle is not directly on the surface of a pBounce region, it doesn't mean it won't be deflected.
I'm not sure how exactly Fusion calculates collisions, but it must have something to do with predictions based on the current velocity (if a particle is rushing towards a region at 3 units per sample and the distance to the region's surface is 2 units, then it's gonna hit the surface).
Strictly speaking, regardless the sampling rate, a particle will rarely be directly on the surface of a region, apart from any specifically designed case.
Yes you are right. It was a fallacy on my side. I thought that the huge subframe accuracy was needed because of the pBounce. Now I see that's not the case, Actually pBounce calculation is very accurate it seems.
Anyone experience particle "popping" in production shots? It looks as though the seed has been incremented or something. Just did a >48 hour render with more than 2 million particles and just discovered that there's a jump at frame 356 (out of 400). I'm trying to narrow it down, but I thought I'd ask around to see if other people had advice.
I would use particle caching to be on the safe side.
I was using disk cache on the pRenders. The sizes of the .part files were all over the place though. Sometimes small, sometimes huge. Not sure why.
Turns out the cache wasn't updating when the upstream tools were invalidated. So for any frame where the .part file existed rendered with one setting, and any frame where there was no existing .part file, the new settings were used. I didn't have the files locked or anything, it just didn't want to resave them. So the disk cache was actually the culprit here, not the solution.