P.S.: just a little example. Colors set to support the demo. Eventually place the spline as well into the Field. Enjoy.

CV4_2026_drs_26_PYeh_01.c4d

Thank you very much for the feedback, entry-newspaper.

If I get the direction where it has to go right, the need would be to have a visual time scale option that provides a loose resemblance to the timeline.
The key component to consider here is, of course, that the whole setup stays intact when the frame rate needs an adjustment for different markets or targets.

Thank you for your patience with this.

My best wishes for your project

Hi entry-newspaper,

I have not found anything that is easier to set up than to use the cache option. Even simple store Velocity actions and replace it for the time being with Velocity zero will not work, as new particles can be created during that time. I might miss an option with Memory nodes, but that is how far I got.

Here is a little example, at 30 the velocity is recorded, at 60 the particles are stopped via velocity set to zero, at 90 the values are applied back from the recordings – note that the constant grow in numbers leaves many pixels out after the recording during frame 30.
CV4_2026_drs_26_PAsp_01.c4d

However, please feel free to suggest/request a Particle Scene Freeze Node: “Share your Ideas” here
https://www.maxon.net/en/support-center

Cheers

Thank you, Marijke,

Here is an example for the 3rd stroke (explosion) and a sketch for particles forth stroke.

It is only a small part of the whole, just to keep the focus on the exploration.

Files:
https://projectfiles.maxon.net/Cineversity_Forum_Support/2026_PROJECTS_DRS/20260122_CV4_2026_drs_26_PYth-ex_01.zip

Render this file.

In this file I used one of your valves. Please advice if that was OK, if not I can replace it.

I hope that has some usable ideas, or at least something that starts a discussion about where you want to go with the H8 engine.
I believe that given that model to ten artists, you will get ten different results, and perhaps all are interesting. Please let me know.

The exhaust fumes inside the muffler are surely pretty fast, and I would expect to see only a gas-like darkening in the tubes. Outside of it, it might culminate in little clouds.
Here is one idea to produce tiny “vdb” files that could be used.
https://youtu.be/6YVd6edVxps?si=5xwZBy8Oltsk-3hY&t=708

I assume you have seen this, but just in case:
https://cineversity.maxon.net/en/series/getting-started-with-cinema-4d-pyro?tutorial=getting-started-with-cinema-4d-pyro-filling-a-box-with-smoke-and-igniting-it

Enjoy

Hi sugar-appeal,

The question leaves some space for interpretation.

Let's start with these two, and please tell me how far off each is to get a clearer picture of what you like to do.
CV4_2026_drs_26_PAfm_01.c4d
CV4_2026_drs_26_PAfn_01.c4d

Please attach a C4D (smaller 1MB) here with your smallest setup.

All the best

Hi Marijke,

Thank you very much, and sorry for the extra work.
I got the file and I will have a look in the morning into it.
(Midnight here)

Cheers

Thank you, Andy.

I learned Xpresso node by node, playing with it.
The typical suggestion would be:
What is in the "wires", knowing the formats, Real, Integer, Vector, to start.
Then pick some nodes and mess around. You know that everything has a learning curve, so take your time.
When hitting a roadblock, please ask! I learn from questions as well. So, never a waste of time for me.

Enjoy

Hi ASeifried,

Thank you for the file and for using Adobe Cloud.

Here is your file back:
CV4_2026_drs_26_XPpc_01.c4d

A short report of the changes:
The font was not included; perhaps the size adjustment is not a fit for your font.
I have set the 0-100 to 0-100% (Per-cent = 100/100). I used multiply here - x 0.01. A habit, as it is safer.
Added a little Add> String to it as an idea, so you can do it with one Text Object
The HUD element in the view can be removed with a right mouse click, and "remove'

Let me know if something else is needed.

All the best

Hi entry-newspaper,

The non-cache workflow could be via Time Scale. This requires for Simulation that should not stop, a different Simulation Scene.

Here is an Example:
CV4_2026_drs_26_PAts_01.c4d

The setup is done in
Attribute Manager> Mode> Scene> Simulation> Scene> Time Scale.

Is that working for you?

Cheers

Hi Marijke,

Thank you very much for the feedback.

As mentioned, I just need a single geometry defining the Cylinder, which should be a small file. Hence, I expected a c4D smaller 1MB that can be attached here.
I try not to be complicated here, sorry if that looks that way.
For security reasons, we have limitations to download only from Dropbox, Google, Apple, Adobe, or Wetransfer, please upload the file to one of these cloud services uncompressed.

All the best

Hi moebious0815,

Thanks for the reply. So, in short, even with 68 bad polygons, you want the algorithm sort it out for you and provide a perfectly solved Boolean operation.

Even some models are based on flat polygons, for example, not even producing a volume" (when you “explode” the collection, you see how unusable it is constructed).

I get your expectation, all of that care to create clean models is not needed; it should work no matter what anyway. Sorry, there's nothing I can help you with.

In short, you state that it is not working, which means you need to contact the Tech Support.
https://www.maxon.net/en/support-center

My best wishes

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

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=u22q06-7oXA

As 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

Hi shoot-laugh,

With "its rotation," you mean the pathway (blue in your image) or the rotation of the coin, like a rolling tire.
Make the Path (in a copy) editable, and use one of its border edges as a new guide. Select the edges and then Main Menu> Mesh> Edge to Spline.
I would use the middle edge of the path to harvest as well as a Spline in the same way, so they are in "sync."

Now you can set up three Nulls:
One that is where the coin touches the path
Second, the same as the first, but a little bit ahead of the first.
Third, the Null that follows the outer edge of the path.

These three create a triangle, which is stable. All three are animated based on Align to Spline, while the second one is a little bit ahead (+3%)
If the first one is animated, the second and the third can use the data in XPresso, so you have to care on end only about only the first.
The first one receives a Target Tag. The Target and Up Vector inside the Target Tag are based on Null 2 and 3.

The outer edge-based spline can now also be treated as a “Rail”. Meaning the coin leans into a curve, or for dramatic effect, leans out of a curve, based on moving the Spline up or down a little bit.

With that set up, the First null can now receive the Coin as a child.

Is that what you are looking for?

Let me know if that needs more data on your side. I'm happy to share, but if you can share teh path set up, it would be easier. (Just the path as c4d file. Thanks.)

Cheers

Hi Pitchi,

Thanks for the file.

I added the needed changes, but I'm not sure how the editor view can create stable data, as the nature of the editor view is to constantly update.

I would use Cappucino to record what you need, if we focus on rendering and sharing the result. Then use a Tracer and follow the Null. In XPresso you can measure the length of the Spline, which might be more accurate than to use previous position. The distance between two points is the shortest possible distance, but how about moving in an arc?

Here is the file back, I used User Data to create a simple and intuitive Variable/memory. The value is reset on frame zero.
CV4_2026_drs_26_XPtd_01.c4d

All the best

Hi notice-world,

Thanks for the file.

Please select your city model and use the Attribute> Mode> Modeling> Mesh Checking.

You might notice that the model has severe problems: 68 bad polygons. The algorithm can't operate on that.

More about this in detail:

https://help.maxon.net/c4d/2026/en-us/Default.htm#html/DMODELING-MESH_CHECK.html#MESH_CHECK_POLY

The problems need to be fixed first. It looks like a CAD model, and my tip would be to check if the export from that software can be improved.
There is no simple "repair", I tried a few first aid options, but none can deal with this.

All the best

Thank you, reading-card, for your feedback.

Please have a look here:

There is this yellow "Flask", and the term experimental. In addition to that, the number of Nodes has steadily grown, while the way to work with those has been optimized along the way. Long story short, it is in progress.

As mentioned, the file was a demo, not a suggestion for production. The Plain Effector shows in an easy way what happens if a polygon-driven change affects a Group. Is that unavoidable? Surely not, with a lot of care, I believe… Which brings me to the point of your request, to have a convenient solution. Which means that the convenience is in the use, not the setup of the tech, and that requires using the "Share Your Idea" here:
https://www.maxon.net/en/support-center
… and ask for a Capsule that does exactly that, Selection-based (Group) Extrusion, while adjustable impact on points by fields as single or in Combination of Fields.

(Yes, I have asked Noseman for input, who is surely the in-house ambassador for Nodes)

All the best

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

Hi reading-card,

Your idea, Zero Extrude and morphing, is perhaps the most approachable way, while the zero amount of extrusion might show Phong artifacts.

After having searched "all" tutorials that cover Scene Nodes to my knowledge, none had an Extrude with Group selection, while each individual point would follow the Field Value separately.

I have attached a demo scene. This is a file to showcase what happened when polygons are elevated differently, as they share points. Again, this is not a production suggestion, just a demo.

I will check more and ask around, as I can turn single posts into Scene node instructions. So far, I was told we handle those for TDs with coding backgrounds. I hope I can find a simple setup.

Here is the Demo-file, green → points; red→ Polygons

CV4_2026_drs_26_ANep_01.c4d

All the best

Thank you very much, entry-newspaper.

Let me know how it goes and what else is needed. I'm happy to look into it.

Enjoy