Pyro Simulation for Engine Combustion in Cinema 4D
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Hello everyone!
I’m currently trying to animate the combustion process of an inline eight-cylinder engine using Pyro in Cinema 4D.
Fresh air is drawn through a pipe into the chamber, where it is compressed by the piston and ignited. The exhaust gases are then pulled out through the exhaust pipe and released to the outside.
I’ve been working on this for quite a while now, but I just can’t seem to get the fresh air and exhaust gases to flow smoothly through the pipes, or to clearly show the combustion happening inside the cylinder. In other words, how the fresh air turns into exhaust gas.
Does anyone have any tips on how I could achieve this?
Unfortunately, my scene file is too large to attach here, but perhaps it can be solved without it or I can provide the scene another way if needed.
Best regards,
Marijke -
Hi Marijke,
This is not a quick setup, and it needs to fit your scene. I have experimented, if I could find some simple setups, but to art direct Pyro in that way, allows for too many variables, to just explore a demo example.
The valves, for example, open typically fast, while the piston is already pressuring the burnt flue out, which is a fast process, and to have colliders working needs a higher sample rate.
I'm fluent in those engines and the mix of pressure from explosion, or piston movement, when valves release the pressure through the more or less "organically" shaped channels of the Valve area, though the muffler, while having to deal with the flow from other cylinders, is not simple. Is it a V8 engine or a boxer, perhaps even in a row, etc? I assume a four-stroke principle, not a two-stroke, going by an 8-cylinder setup.
Another question would be how the filling of the Cylinder needs to be presented, and how the non-pyro (particles, I assume) turn into Pyro, or how to swap them out.
In short, those animations might use footage from explosions (even from Pyro), but I would think that those complex streams of "gas/air" might be better manually animated. At least my Mac gets really slow when I put the number of iterations and collision in, while running small Voxel Sizes.
If you need to do it, I found to separate the ignition and the fuel creates better results, while perhaps using particles for some parts along with Pyro Advect in combination to have faster control over the sequence.
Cheers
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Hello,
thank you very much for your response!
It's a Horch 8 Fiedler straight-eight engine.
At the moment I’m doing everything with Pyro.
There is a particle system for the fresh gas as it flows through the intake pipe. This is currently animated using a spline and a field force.
The next particle system is an emitter that blows fresh air into the chamber as soon as the fresh gas from the previous particle system arrives there (which I can’t figure out, since the smoke always stops moving at a certain point).
The next particle system is the explosion inside the chamber.
After that, there is a particle system that imitates the extraction of the burned residues. The emitter is placed directly at the outlet of the chamber and “blows” into the exhaust pipe. The smoke then follows a spline again, animated with a field force.
And then there is another emitter at the exhaust.The timing of when everything starts is all animated manually with keyframes.
Overall, it simply doesn’t look good yet, and many elements don’t fit together convincingly.
I’m also missing a proper transition between the explosion inside the chamber and the extraction of the residues. I had the idea of animating the color of the fresh-gas emitter, but it doesn’t change smoothly. Instead, it switches abruptly within a single frame.It’s probably all far too complicated on my side.
Is there a way for me to send you the scene?
Nevertheless, I really appreciate your help and best regards,
Marijke -
Thank you very much, Marijke.
I think the separation into several parts is a good idea.
Which might also allow for the reuse of setups for each of the eight cylinders.
I’m sure you have made up your mind on how to present the work, but I'm not clear how the video will show it (the engine block transparent and the full pipeline of gas and fumes as a 3D inside, or the block cut in half, which would also make sense with a straight engine)
The key decision would be to render each part of the four strokes out and composite them, while perhaps blending or using masks to get the best effect.
Particels can be used as Pyro, perhaps creating an easier way to direct Pyro.
Another pointer would be, even given the lower rpm of these older engines, the speed at which all of that happens is not low, meaning that most realistic representations would use a lot of motion blur, making everything perhaps even easier, while applied in post.
One "hack" is the Destructor Setting, avoiding the collision calculation and using the outsed of the Cylinder as Destructor. Perhaps worth a consideration.
https://www.youtube.com/watch?v=_c-mARL7JNA
https://www.youtube.com/watch?v=u22q06-7oXAAs a side note, in the late '90s we had a Rally (Kitzbühl) with the collection of the EFA Automuseum/Amarang cars, and I think we had a Horch 8 in the mix, but I haven’t seen the engine back then.
If you could just copy one cylinder, so I can get the size, etc. The inside polygons where the explosion will sit, and the head with the valve openings, no valves needed. I will replace them here, then share as C4D. I hope that is comfortable for you.
All the best
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P.S.: Perhaps this is a good enough sketch to get some feedback about your target.
My personal take:
Theoretical there is a spark, then an explosion (all white, HDRI screen 4000+ Nits white
), and then nothing that an eye could perceive, as it fights with the after image and anything else is too weak to cut through. Before we even know it, there is the next one.
So, I assume the stylized idea of it is more what one would expect, hence some rough texture, something that makes us feel that flames expand, and is slowed down to explore.CV4_2026_drs_26_PYcl_01.c4d
Preview
https://projectfiles.maxon.net/Cineversity_Forum_Support/2026_Clips_DRS/20260120_CV4_2026_drs_26_PYcl_01.mp4
