MJV

This is the basic premise: ClonerBlendModeMV1.c4d

Short answer is yes you can do it by using the cloner's clones blend mode to transition between different settings in the two sweeps that are a child of the clone.

Good one. Houdini uses Bullet Dynamics which is the same as that still available in Cinema. I stopped trying to use the new unified dynamics in Cinema because it was a nightmare and nothing really worked as expected, and lots of stuff seemed just flat out broken, but as soon as I tried it with the old and reliable Bullet Dynamics it was pretty easy and straightforward and the controls seemed to control things as you would expect. I think you could do the dynamic elements of this animation in either Houdini or Cinema without major differences, but the shading elements would be much easier in Houdini. Working with Cinema sadly forces you to use a separate material for each element, or some other sadistic workaround, instead of just simply changing object or object point colors in Houdini in response to any chosen stimulus. Also, I found no direct way to get an object's direction vector in Cinema and had to build a rig to determine that instead. Also I may have overlooked something but I could find no way to get collision data from dynamics inside of Xpresso, so that would have to be eyeballed or timed out as well. Below is a test I did a few days ago to determine how well I could control the decent rate of the marbles, with one marble hitting quarter notes (180 bmp) and the other hitting eighth notes (360 bmp). In the end I now feel convinced that all these animations you see on Tik-Tok and the like, and in the past, are not using dynamics at all except to get the initial accelerations and velocities that the different curves and circumstances produce. Dynamics is way too variable and unpredictable and hard to control compared to a simple and predictable align to spline animation where the velocities and accelerations are built into the curves, or even a sequence of offset motion clips.

I don't use Redshift but I think a Color MIx node will do the trick as well.

Does anyone care? 🤷‍♀️ Anyway I was thinking ahead to how one would do the step color changes and spins as seen in the original video. For example the ball hits a step and it changes color. It would be simple to do in Houdini by animating objects' point colors while still using just a single global material. Missing stuff like this in Cinema keeps needling at me. It would be so much easier to do this animation in Cinema if things like vector heading and color were object or object point level attributes that could be used directly.

Yes. I can't figure it out.

So I decided to test the above theory and it was much simpler said than done, and working with dynamics was much more difficult than expected. I used Xpresso to determine direction of travel and then place steps immediately in its path, and hoped that dynamics would take care of the rest. In practice dynamics doesn't really take of it as much as you have to take care to dial in just the right settings that make it work. Also I couldn't get the dynamics to work at all beyond a certain short distance range. For example the ball just stops dropping at the very end of this test render. Here is a link to the file if anyone wants to have a look at why the dynamics simply stop working after a short distance: https://www.mvpny.com/MusicBoxMV39.zip

Ok ok but how is the student version coming along in 2042? 😄

Hmm. It's an interesting project. I too have seen these online and wondered how it might be done. It seems like you would only need to generate an object immediately in front of the ball's path for every note, then no matter the shape of the collider or the direction of travel, the animation should work perfectly.

So, this is as far I got, the best result to date, using cloth and rigid body together without baking the cloth animation or other tricks. The video below explains it all. File here in case anyone else wants to have a go at it. https://www.mvpny.com/SolarSystemPracticalGravitySimMV54b33core.zip

Still working on this.

As you correctly noted, simulating real planets in space was not my stated objective. I chose this project originally to test rigid body-cloth dynamics in Houdini and just coincidentally became fascinated in the subject at the same time. Some of my Houdini friends here are already familiar with the project and my interest in it. I revived it to test the unified dynamics in Cinema-20024, but admittedly I haven't gotten it working yet because, in my findings, cloth and rigid dynamics share the same single damping value (which being unified would seem to make sense) but no way to offset damping for one or the other when, as in this case, sharing the same value doesn't work because it's either too strong for one or weak for the other. If you watch Why All Planets are on the Same Orbital Plane above, they show purely 3d simulations at the end, but use the cloth example first to help set up the detail to come . The nice thing about recreating a practical effect such as this marbles on cloth experiment is that you can compare results to your immediate physical environment. For example, we can compare the number of times the marbles orbit the weight in our simulation with how many times they orbited the weight in the classroom test, then compare how well the simulation conformed to the actual result.

Excellent! Thanks for your contribution. Did you use the grain packing method for the marbles? My Houdini subscription is currently inactive but I plan to resume it once Houdini r20 is released in November and I will definitely check out your file first thing then. I found your comment about damping particularly interesting because I tried the exact same thing in Cinema and could not make it work. In my case the cloth becomes unstable as soon as the damping is reduced to the level suitable for the marbles. No matter what I did the cloth became unstable, so it's interesting that it worked for you in Houdini, especially as they both seem to use the same underlying Bullet Engine. I think I will make a separate video to explore that more. I am particularly puzzled as to why there is no control of damping on a per cloth basis, as it seems to be the only real control one has over cloth, even though all cloth abviously is not the same or should behave the same.

This test shows how even in a computer simulation of a real world practical simulation, the theory about why all planets are on the same orbital plane and orbit in the same direction (reposted below) is the result of collisions cancelling out everything else until everything resolves to one orbit direction. Notice in the Cinema simulation how all the marbles are orbiting in the same direction by only the one third mark.

I faked the rigid body dynamics working simultaneously with cloth here.

Here is the file as far as I got with it so far. SolarSystemPracticalGravitySimMV43.zip I discovered that there is no way to do both the cloth and the rigid body simulations at the same time because of what seems like a limitation. Every cloth simulation I tried required a high damping value in project settings. So maybe a damping value around 12% at least to get stable and realistic cloth. The marbles on the other hand, in order to roll realistically (for longer than a few seconds) in this scene require a damping value of not above about .25%. Cache the scene after download for full effect:

I made this short screen recording to show how fast a cached file plays with the Octane Live Viewer open and well the motion blur renders even as the file plays.

Thanks. I remember I toyed with that a bit at the time but was a novice so may not have, probably didn't, set it up correctly, but I would be surprised if that worked with the efficiency needed for the expected result. I don't know for sure though.

Thanks. Not at first but aoktar over at OTOY Forum enlightened me. Once I cached the sim it works great and even much better than I expected, as I reported to aoktar. Once cached I discovered that the motion blur renders blazing fast and I can be seen clearly even while the file plays in the live viewer. It's freaking amazing!

Thanks for contributing. So the spheres in this animation are soft bodies with a shape match constraint. Yes?

In case any Octane users are reading this thread, I discovered yesterday that Octane render Cinema 2024 Beta cannot render motion blur when using the new rigid body dynamics. I've reported this to Otoy and hopefully they can fix it, but this throws a serious crimp in my plans to render this with Octane, as it's meaningless to have dynamics, no matter how good they are, that can't be correctly rendered. Test file attached below: OctaneMotionBlurMV3.zip

No not yet. What you see so far is all rigid body dynamics except that the net was deformed first as a soft body but then was converted to a hard body. Keeping the net as a soft body introduced too many variables at a time for me to know what caused what. Now that I have it basically working at least as a rigid body sim my next step is to try to keep the soft body. I'll post any results I get.

Here is what I have so far playing while Octane Live Viewer is active.