Pyro - Slow motion

[CaseyV]

Hi there,

I'm trying to create a slow motion Pyro sim.
I have a good setup with a normal frame rate of 25fps.
When i change the projects frame rate to 200fps, the simulation barely exists, there's not much fire or smoke etc.

There is mention in the release notes that there is a "simulation time scale", but i cannot find that setting anywhere.

Any help would be appreciated! or advice on how to slow down the simulation.

[Dr. Sassi]

Hi CaseyV ,

I knew it was there, but I had to ask, and the manual doesn't explain it in any text form (I have to file a report), so thanks to Noseman!
It is in the Attribute Manager> Project Settings> Simulation> Scene

All the best

[CaseyV]

Thanks for the response Dr. Sassi,
Unfortunately this has the same effect as setting the frame rate higher, it completely dampens the simulation. It doesnt just make is slower. If you try with a simple sphere and default pyro settings, then adjust the scene time scale down to .25 (1/4 speed), the simulation barely flickers with a flame.
The only way to counter this seems to be to up the fuel and pyro settings to make a more powerful pyro simulation, which is then so powerful and fast, that it negates the speed slow down.

Embergen has a hz setting that just slows down the simulation exactly how it should. I was hoping i wouldnt have to jump over there to create a vdb, as the current pyro object with an octane tag works very well!

[Dr. Sassi]

Hi CaseyV,

You asked about the parameter. I shared that. I will look this evening into the 24 to 200 "translation", hopefully you share a file.

I have no idea about the Hz (Hertz) implementation of Embergen, if it rules the whole set of influences and expresses it in return as values in the cache while acknowledging the Substeps, etc.

The following tutorials do not provide the 24/200 fps request but perhaps hold some ideas.

Candle fire is discussed here:
https://cineversity.maxon.net/en/series/getting-started-with-cinema-4d-pyro?tutorial=getting-started-with-cinema-4d-pyro-burning-candle-small-scale-pyro

Is this perhaps what you like to achieve:
https://cineversity.maxon.net/en/series/getting-started-with-cinema-4d-pyro?tutorial=15-getting-started-with-cinema-4d-pyro-freezing-a-pyro-simulation

Would you mind sharing a scene file with your target setup while describing what you need (storyboard, perhaps)? I will take a look at it. Without it, it is hard to say.

All the best

[Dr. Sassi]

Hi CaseyV,

To create a slow-motion Pyro.
Set your Attribute Manager> Project> FPS to 200
The frame max to 200 if 8 seconds in your 25fps are the target.
(Some might say 0-199 equals 200 frames, but take that one frame as padding.)
Leave the Time scale alone, don't touch it at any time.

Set up the Pyro as you need; again, one second now is 200 frames, but eight in 25fps later on.

When the result is to your liking, cache it.

Now go to the main scene with your 25 fps setting.
Set up the Pyro and load the 200fps cache into the Pyro (Default)
Your pyro result should show now eight times slower.

Alternatively, the Volume Loader allows the high frame rate cache to speed things up if needed.(To the max of the cache [200 in this example], after that, it has not a good quality)

The RS Volume option allows for even more.

With these last two suggestions, a project can even produce a wide variety of output frame rates without changing the appearance. Tests for specific setups are suggested.

Enjoy

[CaseyV]

Thank you Dr Sassi.
I guess my main issue is, you cannot create a pyro simulation at a regular frame rate (e.g. 25fps) and then adjust the frame rate afterwards.
Seemingly the only way to achieve a simulation that replicates one created at 25fps, when the project settings are at 200 fps, is to adjust the temperature of the pyro to the highest it allows.
There is no parity between different frame rates in the simulation. You cannot just change the frame rate and achieve the same look. The frame rate should have no effect on the attributes of the simulation itself, but the frame rate wildly effects the simulation itself.

The simplest example of this i can show, is simply dropping a pyro tag on a standard sphere at 25fps, without changing any settings, leave at default, and run the simulation.
Then adjust the project frame rate to 100fps, and run the simulation again.
The simulation is drastically different, although none of the settings have changed.

[Dr. Sassi]

Hi CaseyV,

Yes, that is the point. Hence why I gave you a procedure that eliminates all influences that prevent it otherwise.
I have made a feature Request to have this as an option. It should be possible to get from 24fps to 25fps to 30fps, etc., without any concerns about changes.

If the app would work on a simplified idea of Pyro, I could see that easily done.
But my personal impression is that the complexity is working against it.

For example, Gravity results in an acceleration expressed in m/s^2, which means it doesn't have a linear relationship to fps. So what is wanted is an artist call, slow it down, and violate the physics of time or following gravity laws? We can't have both. Not to discuss it here, but to leave this as an example that things are often not as simple as push of a button decision.

Cinema 4D should be easy to operate and art direct, at least to my understanding. So I will also prepare some suggestions toward this. After all Pyro is the first release.

So, since this is a Q&A forum, I have to ask you to either go to the support and communicate this as a problem or go to the "Share Your Idea" option and suggest what you need to have it working for your needs. I certainly will you support with that.
Both options are here:
https://www.maxon.net/en/support-center

More I can't do for you now in this case.

My best wishes for your current project