r/Simulated Sep 22 '18

Meta What is a simulation? A detailed comparison between Animation, and Simulation.

978 Upvotes

Ever since this subreddit started getting more traction, more and more people began posting non-simulation videos. In each of these posts, users will comment something along the lines of "This is not a simulation," and an argument would ensue. So I am writing this post to, hopefully, end this never-ending cycle. I hope the mods do not remove this post, because I think it could end much of the hostility in the comments around here. Perhaps this could even be a stickied post, so all new users see it.

What is a simulation?

According to the dictionary, the word simulation is defined as, "imitation of a situation or process." However, this definition does not actually constitute what a simulation is in the world of CGI. In CGI, simulations are essentially visualizations of real-world processes that are generated using mathematical models. That is to say, the final product of a simulation is something that was created using fundamental rules of nature or some system, such as Newton's Laws of Motion, Fluid Dynamics, or various other mathematical models. In a simulation, it is often the case that each frame was created by manipulating information from the previous frame.

How are simulations different from animations?

It's quite common for animations and simulations to coexist in one medium. There are plenty of simulated components in animated movies, such as Disney's Frozen (Snow simulation), and Hotel Transylvania 2 (Cloth simulation). However, simulations and animations individually are very different by nature. As previously stated, simulations try to model real-world processes, and use mathematical models to generate necessary data. Animations, on the other hand, are usually created through a manual process. Animators manually keyframe the attributes (position, rotation, scale, etc.) of objects in a 3D scene. It's possible for manual animations to look convincing, but that does not make them simulations.

The "Ray tracing)" argument.

Many 3D rendering engines use a process called "ray tracing" to create images of a 3D scene. For anyone who is unfamiliar with ray tracing, here is the definition from Wikipedia:

In computer graphics, ray tracing is a rendering) technique for generating an image by tracing the path of light as pixels in an image plane and simulating the effects of its encounters with virtual objects.

Because of this definition, many people argue that any 3D render is a simulation, so long as it was rendered using ray tracing. By definition, it is true that the process of ray tracing is a simulation. However, this argument is very silly because the entire purpose of the term "simulation" in CGI is to make a distinction between what is manually created, and what is created using the previously talked about mathematical models. Therefore, when we discuss simulated graphics, ray tracing is not considered a simulated process.

Examples of animated (non-simulated) posts:

  1. "Satisfying simulations" - 3.4k upvotes
  2. "Bender's old job" - 2.2k upvotes
  3. "Up or Down?" - 1.4k upvotes
  4. "Adobe Dimention Rendering" - 1.4k upvotes
  5. "Depression - Robert Ek"

Many of these animated posts accumulate upvotes, and sometimes they stick around for a few days before getting removed. Because of this, new users who see these posts get a false idea of what a simulation actually is. Hopefully this post was informative to any newcomers. If you would like to suggest edits, please comment.


r/Simulated 15h ago

Various Pneumatic Simulation Sandbox

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37 Upvotes

I've been working on a pneumatic engineering sandbox in Unity.

The wheel isn't driven by a motor, it's powered entirely by a pneumatic cylinder using Unity physics.

The machine is built from modular components: air sources, hoses, 5/2 directional valves, cylinders, buttons, regulators, and more. In this demo, a button pilots the valve, which alternates air between each side of the cylinder to extend and retract it, turning the wheel through a crank.

My goal is to let players build anything from simple vehicles to ridiculous pneumatic contraptions. Alongside sandbox mode, I'm planning engineering puzzles, vehicle challenges, and automation. The logic system already supports AND, OR, and NOT valves, so players will eventually be able to build things like counters, calculators, and even simple computers.

It's still early in development, but I'd love to hear what you think or what kinds of machines you'd want to build.


r/Simulated 5h ago

Blender Blender - Hydrothermal Vent - Links in comment

5 Upvotes

r/Simulated 2d ago

Research Simulation Graph War between 2 Genetic Algorithm

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34 Upvotes

Trickshot vs Evolution bot: Graph war

Both are Genetic Algorithm

Trickshot GA: Optimized for Tricks

Evolution GA: Optimized for gradual, generalized adaptability

(Minimax was used as an Observer. Not an active player

I should have mentioned that)


r/Simulated 1d ago

Proprietary Software 3D Torus Game of Life Conflict Simulation [OC]

1 Upvotes

https://reddit.com/link/1uxa1j5/video/zh2magwy1fdh1/player

I built a custom 3D WebGL renderer to simulate Conway's Game of Life meta-rules ("Adversarial Conway"/HASHWAR) wrapped around a 3D Torus.


r/Simulated 2d ago

Houdini SYNTHESIS - A little simulation clip from a music video I made in Houdini, Maya, Nuke, Resolve & Redshift. Lots of other sims in the full video, link in the comments.

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60 Upvotes

r/Simulated 1d ago

Interactive A browser toy where creatures made of particles hunt, flee and > graze — every species is just 6 numbers

0 Upvotes

This is built on Particle Lenia, an artificial-life model from Google researchers.

Each particle descends an energy field created by its neighbors, and an entire species is defined by just six parameters.

I added cross-species senses—hunters are attracted to prey fields, prey avoid hunter fields—plus food, walls, and goals. The result is a strange little ecosystem garden.

Nothing is scripted or animated. The layered membranes, the chase behavior, and the way colonies merge and split all emerge from the underlying math.

Play it (free, in-browser, ~70 KB):
https://leonbzt.itch.io/particular

Read about Particle Lenia:
https://google-research.github.io/self-organising-systems/particle-lenia/


r/Simulated 3d ago

Proprietary Software Spent the last 3.5 years building a real-time 3D physics simulation for sound

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77 Upvotes

As the title says, I've spent the last 3.5 years working on Anukari, a 3D physics simulation much like a video game engine, except that instead of running at 60 steps per second, it runs at 48,000 (or more) steps per second, so that the physics systems can vibrate at audio frequencies. It's commercial software; primarily I am selling it to musicians and sound designers to use for music, sound effects design in film. But also it's pretty fun for non-musical people who just like building weird physics stuff. The main website is https://anukari.com

I have written extensively about the development work, for people who enjoy the nitty-gritty details of that sort of thing: https://anukari.com/blog/devlog

For the 1.0 launch I was focused on making it super performant and reliable with the basic set of the most interesting physics features, but for upcoming releases I'm working on more interesting physics features. For example, today the springs are linear f=-kx, but I'm experimenting with nonlinear springs with dead zones, and also push/pull-only springs (ropes and collisions). I'm hoping that sales will fund development basically forever, and that I can just keep making the simulation more and more rich over time.

There's a long history for this kind of spring-mass simulation being used for audio. I've had early Beta users write in about the GIPSY Lab in Grenoble, France working on this possibly back into the 1970s. More recently there was CORDIS-ANIMA, another academic research project. One dream of mine would be for sales to be good enough to fund the making of a deep documentary about the full history of such projects. But that's a pretty big stretch goal... :)

I love chatting about this stuff so feel free to ask me any questions about how the simulation works, etc!


r/Simulated 4d ago

Research Simulation I simulated 40 years of natural selection in Galápagos finches (based on Grant's real data)

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73 Upvotes

Been working on agent-based simulations lately and decided to try modeling something with actual historical data behind it.

Each bird is an agent with a heritable beak size. Fitness is calculated against the available seed distribution - droughts shift the mix toward hard seeds, which favor larger beaks. Birds that can't crack enough seeds lose energy and die. The survivors reproduce, passing their beak size (with some mutation) to offspring.

I tried to match the key events from Peter and Rosemary Grant's 40-year Daphne Major study. The severe 1977 drought, the 1983 El Niño reversal, a 1987 drought, the G. magnirostris competitor arrival in 2004. The beak size shifts in the simulation roughly follow their published numbers.

The hardest part was calibrating the El Niño phase. If selection pressure is too sharp, the birds never recover the reversal. Took some fiddling with fit_sigma and seed distribution ratios to get something believable.

Birds are color-coded by beak size (olive green = small, orange-red = large) so you can see the population shift without reading the chart.

(speed up 2.5x)


r/Simulated 4d ago

Proprietary Software Conway's Game of Life battles itself on a torus

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37 Upvotes

This showcases the "Adversarial Conway" algo that lets two individual Game of Life patterns compete on a shared space, the titular Torus (see GitHub repo). The pattern's evolution in combination with a seeded RNG determines the paths they take to claim the available territory.

These video snippets are part of a knock-out style tournament that pits 16 such patterns against each other to determine the weekly champion.

GOL patterns are specifically sought for their longevity and must have a generational count within certain limits to be elligible for being drawn in the competition.


r/Simulated 4d ago

Interactive Chaotic Double Pendulum Simulation [OC] | SFML C++ |

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18 Upvotes

I have been working on a Double Pendulum simulation for the last few weeks, and I'm very happy with the results. Although it might not be the most accurate simulation, it demonstrates the chaotic nature of the double pendulum very well!

The simulation has tunable parameters and even a Multiple pendulum mode where you can have more than one pendulum with differences in angles, length, mass, etc to see how quickly they diverge even with small differences. The simulation was made using SFML and ImGui libraries in C++. Behind the scenes, I learned and used the RK4 method for solving the accelerations and velocities.

The simulation is available to download for windows here on itch: https://alifnull.itch.io/double-pendulum


r/Simulated 5d ago

Houdini Houdini Pyro advect Particles Breakdown

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20 Upvotes

r/Simulated 5d ago

Various N-body simulation of Jupiter vs. black hole on mobile

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16 Upvotes

The application is called Space Crash Simulator.


r/Simulated 5d ago

Research Simulation [OC] Barnes-Hut 3D N-body simulation of 500k particles in real-time on a laptop GPU

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46 Upvotes

Two spinning disks of ~250k particles each, simulated and rendered in real-time on my RTX 500 Ada laptop GPU at ~30 fps, using my custom implementation of the Barnes-Hut algorithm in CUDA. Code: https://github.com/lechebs/nbody


r/Simulated 4d ago

Research Simulation Developing a new kind of particle simulator—would love to hear your thoughts!

0 Upvotes

"I'm building something new for particle simulation lovers."

I wanted to share a sneak peek of a project I’ve been working on. It’s a particle simulator where you can build worlds, adjust parameters, feed the particles, and even cause total destruction—all while vibing to a great soundtrack.

It’s still in the beta stage, so it’s not ready for everyone just yet. However, I’m excited to polish it up and share the full experience with you soon!


r/Simulated 6d ago

Research Simulation [OC] I built a 3D browser-based Asteroid Tsunami Simulator using CesiumJS & Next.js

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14 Upvotes

Hey everyone,

I wanted to share a side project I’ve been building: a 3D global tsunami simulator that runs entirely in the browser using Next.js 14, CesiumJS, and Mapbox for terrain and satellite imagery.

The video shows an observer-viewpoint render of an incoming deep-water wave.

Link to try it yourself:https://tsunami-simulator-xi.vercel.app/(Free, open-source, no account)

How the simulation handles logic:

  • Custom Impacts: You drop a red epicenter and a blue observer anywhere on the globe, tune asteroid diameter (100m – 10km) and velocity (11 – 72 km/s), and hit IMPACT!.
  • The Physics: It calculates kinetic energy, scales initial wave height, tracks radial dissipation, and computes wave speed dynamically by sampling bathymetry along the great-circle path from the terrain data. It applies Green’s law for coastal shoaling as it approaches the observer.
  • Camera Modes: You can toggle between Globe, Observer (eyewitness), or Auto camera tracking, adjust observer altitude, and scrub/rewind the playback countdown.

Historical Archives Included:

Beyond custom strikes, I mapped out ~28 historical tsunami events (like 2004 Indian Ocean, 2011 Tōhoku, 1883 Krakatoa, and ancient paleotsunamis) and 7 historical impacts (Chicxulub, Tunguska airburst, etc.). For the historical modes, the animations script-illustrate documented run-up heights and arrival times from scientific literature.

It's not a full CFD or NOAA-grade hydrodynamics model, but a highly visual, physics-principled global renderer. I’d love to get your thoughts on the rendering performance and the UX!


r/Simulated 6d ago

Research Simulation PF-FLIP vs ST-FLIP simulation WIP example

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5 Upvotes

Hi,

Testing my new PF-FLIP vs ST-FLIP workflow based on SIGGRAPH papers 2025 / 2026.

ST-FLIP is a nice addition to PF-FLIP base which I am testing at the moment.

Made several posts in blender subreddit about my Atlantica plugin. Recently I had a progress with a proper multigrid simulation.

I tested it recently only on Apple M CPUs, my PC / Nvidia path is waiting for it.

Main lessons:

M architecture is very efficient while switching between CPU / GPU because of unified memory.

ST-FLIP runs ~1.5–3.4× higher peak velocity at the impact in meteor test example. I need to check CFL convergence. So it's still WIP.

Feel free to reach me in DM if you are interested in method.


r/Simulated 6d ago

Proprietary Software Nora Kinetics // Fully Custom Destruction Engine

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1 Upvotes

Hi folks!

I wanted to share the newest demo video for my custom physics engine and renderer: Nora Kinetics.

I've been developing Nora Kinetics for about a year. It was initially inspired by this research paper on Stable Cosserat Rods: https://dl.acm.org/doi/10.1145/3721238.3730618 . I had been wanting to learn about compute shaders and graphics programming, so this felt like a good starting point.

You can see more of the Cosserat rod side of things here: https://www.youtube.com/watch?v=TS2WOsfrac8

It is built on top of Apple Metal because that's where I was able to get the best performance early on. The physics is 100% GPU driven and the CPU acts as a lightweight coordinator. The lighting and rendering is all custom as well. It can run on an iPhone at about 60fps with 20k segments and on my MacBook Pro (M5), it runs at 120fps with about 250k segments.

This newest video shows the rigid-body destruction system that I finally finished implementing. It runs along side the Cosserat solver and they communicate through GPU buffers so that they can remain in sync.

I'm aiming for an App Store release in the Fall. It will be more of a sandbox / creative engine to start, but I'm also working on a Scratch style programming agent that lets you generate emergent behaviors from the little segments. Each one gets its own little brain and you are able to tell it what to do. Some of the creations I and some of my testers have made so far are pretty cool!

If you'd like to be a BETA tester, let me know! At the moment, I'm looking for testers with a Mac with Apple Silicon (M1 or higher)

Thanks for taking a look!

Happy to answer any questions!


r/Simulated 6d ago

Research Simulation No dark Materia

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0 Upvotes

r/Simulated 7d ago

Blender Car Crash Simulation In Blender

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73 Upvotes

r/Simulated 7d ago

Proprietary Software Practicing in Endorphin

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13 Upvotes

Composition in blender, still working on it


r/Simulated 8d ago

Interactive Art Gallery Problem Visualization

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10 Upvotes

r/Simulated 9d ago

Research Simulation Polywell fusion ignition fail

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25 Upvotes

Simulated a small polywell fusor


r/Simulated 10d ago

Houdini The smoke moves along the curve

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213 Upvotes

r/Simulated 10d ago

Blender Green Gloop (Nexus Insydium Addon)

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78 Upvotes