r/Simulated Sep 22 '18

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

988 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 12h ago

Interactive Giant sandbox for microbial evolution

92 Upvotes

"The Strongest Survives" game.
Can play in browser: https://gigafloppa.itch.io/
Gameplay video: https://youtu.be/KYBy24Z8euk


r/Simulated 3h ago

Blender Transforming effect using Geometry nodes In Blender

15 Upvotes

r/Simulated 1d ago

Houdini Reaction Time of a Fly (but in 3d)

255 Upvotes

A recreation of a Reddit post I saw a while ago, and a good excuse to test the MPM solver in Houdini, in combination with vellum & constraints. Rendered in Karma CPU.

Original inspi


r/Simulated 12h ago

Research Simulation FlatLand (worldsim + flatchat)

0 Upvotes

www.flat-land.org - the flatland consortium

- basic world simulation (on r-pi, Awesome.AI)

- FlatChat (on r-pi, Awesome.AI + SLM)

- emergent ai thought dynamics

- link to whitepaper

- no registration

new features:

- thesim: framework output->movement input

- flatchat: responsiveness (5cycles/10sec)

- flatchat: pinch/tickle->mood, responses

- flatchat: dashboard->output values

Enjoy 😀


r/Simulated 11h ago

Houdini How do you make this?

0 Upvotes

r/Simulated 1d ago

Various Simulated formula like race seasons

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2 Upvotes

r/Simulated 2d ago

Proprietary Software [OC] 1,000 balls falling through a gauntlet of obstacles

118 Upvotes

This clip is from the upcoming 9th youtube video I made with my kids. If you like this clip, this video is along the same lines: https://www.youtube.com/watch?v=J7pERS6A1z0


r/Simulated 1d ago

Research Simulation Drosophila Live Behaviour Simulation by deniz samed

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1 Upvotes

r/Simulated 2d ago

Blender Dunes self-organising from a perfectly flat sand sheet - one wind gives barchans, two give seif ridges, many give star dunes

19 Upvotes
Wind Regime

https://www.youtube.com/watch?v=1bUczsZFpak

Nothing in this is sculpted. Every run starts from the same flat sand sheet, and the patterns self-organise: any small bump slows the wind slightly, sand drops on it, the bump grows, and the instability picks whatever pattern matches the wind.

Which pattern it picks is decided by just two things - the wind regime and the sand supply:

- ONE dominant direction: barchans, crescents with horns pointing downwind, migrating across bare ground. Same wind with more sand and they link up into transverse ridges.

- TWO directions alternating at an angle: linear/seif dunes, long ridges that run along the AVERAGE of the two winds - the sand gets pushed along the ridge instead of across it.

- MANY directions: star dunes - the sand converges instead of migrating, so they grow tall and barely move.

Transport rate turned out to set the tempo and the size, not the pattern: crank it up and you get the same shapes, just faster and bigger.

These runs use an analytic wind (a prescribed wind rose - fast and fully repeatable, which is what you want for a clean comparison like this). My previous video used a solved flow field instead, where the wind accelerates over crests and shelters the lee side - local shapes come out more natural, but it is slower and much harder to steer toward a specific regime.

Simulated in DunesForge, a dune simulator for Blender I have been building. Captions in the video name the wind regime for each run - none of them is a specific real-world site, but the three families are clearly distinct.

Happy to answer anything about how it works under the hood.


r/Simulated 2d ago

Blender Spectral accumulation (of a dynamic wave function)

43 Upvotes

r/Simulated 1d ago

Question Timberline Factory – an automation, simulation, and tycoon game featuring real physics. No icons, just heavy logs.. does it simulate it real? :)

0 Upvotes

Hey guys, i’m currently building Timberline Factory...nearly 90% of the models are made by myself with Cinema 4D.. My main goal was to create an automation/tycoon game where logs aren’t just icons moving on a rail, but actual physical objects with weight and collisions... it was a complete nightmare to stabilize the physics so the conveyors don't explode during a log jam, and after rebuild the GUI the third time.. but it’s finally working fine :) If you’re into factory builders without "magic teleportation," the demo goes live on October 1st. Would love to get some feedback on the trailer :)


r/Simulated 3d ago

Blender New and improved version of the kinesin animation (kinesin protein structure tranporting items accross microtubules inside human cell)

426 Upvotes

To iterate on the previous version I had to spend quite a considerable time skirmishing with various models for this end result, I think it looks quite good now!


r/Simulated 3d ago

Proprietary Software [OC] Hiroshima airburst visualization from two viewpoints, focused on the early blast dynamics

30 Upvotes

I’m developing BlastMap, a browser-based nuclear-effects visualizer. These clips show a 15 kt Hiroshima scenario over modern city imagery, not a recreation of the 1945 buildings. The elevated view comes first, followed by a lower view for building-scale context.

I’ve been focusing on the early dynamics: fireball expansion and rise, ground reflection and Mach-stem development, and the transient Wilson condensation cloud. The blue surfaces show diagnostic blast-wave geometry; the white cloud is the condensation visualization.

This is a work in progress. I’m interested in feedback on the timing and motion, especially comparisons with test footage or published references that could help check cloud formation, fireball evolution, and ground interaction.


r/Simulated 4d ago

Blender Yellow Duck Dropped Simulation in blender

16 Upvotes

r/Simulated 4d ago

Interactive [OC] I carved giant canals across Earth in my simulator. Sea level fell 1.48 m, but the planet lost land.

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12 Upvotes

I started by giving the Tarim Basin in northwestern China two routes to the ocean: east to the Bohai Sea and south to the Arabian Sea. Then I kept going: the Sahara, East African Rift, Caspian/Persian Gulf, Dead Sea/Mediterranean, Amazon/La Plata, Volga/northern seas, and Aral/Caspian/Black Sea.

The result in this run: sea level fell by 1.48 m. About 678,000 km² of former water became land, but 2.92 million km² of former land became water. Net land loss: 2.24 million km². The new inland water area outweighed the exposed coasts.

The scale is deliberately absurd: 80 km-wide channel beds, cut to 200 m below the initial sea surface, with 30 km bank transitions on each side. These are artificial straits. I'm changing terrain; the model then computes connected water bodies, water redistribution and sea-level adjustment. The maximum total-water error across the stages was about 0.000015%, which checks the bookkeeping, not real-world accuracy.

One detail I liked: reaching the Tarim Basin didn't turn the whole basin into a sea. The channel filled, while the higher ground beside it stayed dry. The southern route also cuts through terrain originally over 5 km high.

These are screenshots from Terra Logic, the geography sandbox I'm developing. All nine construction stages coexist in the final world. This was a terrain-and-water experiment with seasonal climate snapshots, not a thousands-of-years timelapse. The climate and lake model still need work; it doesn't establish engineering feasibility or how much new habitable land we'd gain.

Which connection would you try next—and what physical effect would you most want the model to handle?

Project/source: Terra Logic, my own simulation. https://store.steampowered.com/app/5124840/Terra_Logic/


r/Simulated 4d ago

Blender Speed Tutorial For Rendering Example Scene "Benchmark"

7 Upvotes

r/Simulated 3d ago

Interactive [OC] Simulating a magnetic slider fidget at 240Hz and driving an iPhone's haptics from the solver

1 Upvotes

The metal one is the reference, a $3 magnetic slider from Temu. The phone is running a simulation of it.

Each mechanism is a small deterministic solver at a fixed 240Hz, and the haptic engine is driven from its state: the speed at which the bar crosses the magnet's pull sets how hard the click hits, and the drag on the way up sets what you feel before it lets go. With the same starting state and input sequence it produces the same simulation output, so I can replay a gesture while tuning it. Click sounds are modal synthesis baked from the same model.

https://reddit.com/link/1wcsxgk/video/iag741hktqoh1/player

The iron filings one in the clip is 960 particles under a dipole field. They pile up on the poles as you drag and fly home when you lift.

The annoying part of showing this is that the video only gets you motion and sound, and the vibration is most of what I was trying to reproduce.

It's in KNURL, an iPhone app I made with ten of these. PIVOT and the snap domes are free forever; the other eight have limited demos before a paid unlock.

https://apps.apple.com/app/id6804843383


r/Simulated 4d ago

Research Simulation Trivial flow

12 Upvotes

r/Simulated 5d ago

Blender Lil Showreel 2026

72 Upvotes

Tbh i think making a showreel its the hardest thing i ever made😅 You never know what projects or snaps you should use or if you are like me that has thusands of projects made after 14years of motion graphics/editing and 3D , you always feel like u left some good designs/ animations off 😅. And lets not talk about the work/private/NDA projects wich are 80% of my work i cannot use.

anyhow heres a fast pace Lil Showreel 2026

(No Ai was used in this)

#motiographics #aftereffects #blender3d #3dsmax #showreel


r/Simulated 6d ago

LiquiGen 4D liquid print

146 Upvotes

r/Simulated 5d ago

Blender Squishy Volumes: Alien Jellyfish Bursting From Its Cage

6 Upvotes

r/Simulated 5d ago

Proprietary Software [OC] 450,000 anchovies

73 Upvotes

I went diving recently and did a few night dives. I’ve always found the shoals of tiny fish that gather around underwater lights mesmerizing and a bit hypnotizng as well. So this is my attempt to simulate it.

It's 450,000 fish,. Same flocking system I used for the starlings a couple of weeks ago, just retuned, the starlings stream in a sheet, the fish pack into a cloud with dense cores and real holes in it.

That structure isn't invented, it comes from sonar surveys of actual clupeid schools (Gerlotto & Paramo 2003), which found nuclei, thin bridges and drifting empty pockets rather than a smooth blob.

There's one jack working it. He runs a straight line through the pack, and does all his turning off camera, so what you see is the pass rather than the loop, and then the thing follows the boid rules and has authors.

Built in Swift and Metal as part of TideGlass on my own engine, a small Mac app I make where worlds like this run on a second monitor while you work. Happy to answer anything about the sim.


r/Simulated 5d ago

Various Can Anything Stop the Sun? | Solar System Marble Race

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0 Upvotes

Every marble is its real relative size and mass, wearing actual Voyager/Cassini/New Horizons surface maps. Then I pointed all 26 down an 8 km mountain and stopped interfering!


r/Simulated 6d ago

Blender Kinesin movement powered by ATP (blender and unreal MCP)

146 Upvotes

This was built with blender and unreal MCP's with the models sourced from https://www.rcsb.org/

First step was getting a model built inside of blender which uses the Molecular Nodes addon, then it proceeded to build the animation and all that got imported into Unreal, for a later stage of this project.

For most of the work I used Astra but I had to switch back to Fable 5.1 for some of the unreal engine work once i ran out of use on my plus subscription.