Hi!

I was wondering how I could make a realistic combustion simulation as a project for fun. I know that making a realistic simulation of a combustion reaction in a car from scratch involves a good amount of math and physics. Does anyone know how to go about this?

https://techcrunch.com/2025/01/06/google-is-forming-a-new-team-to-build-ai-that-can-simulate-the-physical-world/

Hi folks,

I wrote a guide on discrete-event simulation with SimPy, designed to help you learn how to build simulations using Python. Kind of like the official documentation but on steroids.

I have used SimPy personally in my own career for over a decade, it was central in helping me build a pretty successful engineering career. Discrete-event simulation is useful for modelling real world industrial systems such as factories, mines, railways, etc.

My latest venture is teaching others all about this.

If you do get the guide, I’d really appreciate any feedback you have. Feel free to drop your thoughts here in the thread or DM me directly!

Here’s the link to get the guide: https://simulation.teachem.digital/free-simulation-in-python-guide

For full transparency, why do I ask for your email?

Well I’ve written a book and developed a course on discrete-event simulation in Python. These are both all about real-world modelling and simulation with SimPy, and I’d love to keep you in the loop via email. If you found the guide helpful you would might be interested in my course or book. That said, you’re completely free to hit “unsubscribe” after the guide arrives if you prefer.

We’re kicking off the first challenge in r/simulate, and this one’s all about bringing nature to life—digitally. Your mission: build a predator-prey ecosystem simulation. Think wolves chasing rabbits, sharks hunting fish, or maybe your own weird and wonderful food chain (floating jellyfish aliens feeding on radioactive plankton? Go for it!).

What’s the Deal?

Create a simulation that shows off how different species interact and evolve over time. Start simple (just two species is totally fine) or go big—add seasonal changes, migration patterns, resource depletion, disease spread, or whatever makes things feel real and dynamic.

Suggested Tools & Approaches

• Python (Matplotlib, NumPy, PyGame)
• Jupyter Notebooks / Google Colab
• Unity, Processing
• Excel, Google Sheets
• JavaScript & p5.js
• AI Coding Assistants (e.g., GitHub Copilot, Code Llama)

Honestly, use whatever makes sense to you—no limits here!

Judging Criteria

1. Realism: Are the predator-prey relationships believable?
2. Creativity: Unique species, clever dynamics, environmental twists.
3. Presentation: Show your work! Visuals, explanations, and maybe a narrative to help us get into your world.

How to Submit

• Post your submission as a new thread in r/simulate by July 31, 2025.
• Include:
  • A short video or GIF showing your sim in action.
  • A link to your code (GitHub, GitLab, etc.).
  • A brief write-up on what you did, how it works, and what you learned.

The Prize

Winners get a special flair and the pride of being our first challenge champion. More than that, this is a chance to stretch your skills, learn something new, and share your experiments. Don’t worry about perfect—just go for it.

Any questions or ideas? Drop them below!

Hi everyone,

I'm currently working on a project where I need to make a counter based on the number of entities that spend less than 15minutes since their arrival to the first server until they exit the last server. I know how to calculate the time between the servers, but how can I make a counter based on this time?

I'm running several scenarios in Process Analyzer, and I couldn't find a way to export all the results to anything other than the average values or in the form of graphs. I found out about an R package that consolidates the csv summary stats reports, but I would need to run each scenario individually. Is this impossible to do via Process Analyze? I'm talking about 30 runs of 53 scenarios, so I'm really unwilling to do it manually. Thanks in advance!

I am making a game and would like to include a semi realistic tile base atmospherics simulation I have been reading a lot about gas laws but don't know where to start. If anyone has any resources they recommend that would be awesome.

I am trying to use randomTrips, but when trying to use the command, I am given this error:

usage: randomTrips.py [-h] [-c FILE] [-C FILE] [--save-template FILE] -n NETFILE [-a ADDITIONAL]

[--weights-prefix WEIGHTSPREFIX] [-o TRIPFILE] [-r ROUTEFILE] [--vtype-output VTYPEOUT]

[--weights-output-prefix WEIGHTS_OUTPREFIX] [--pedestrians] [--personrides PERSONRIDES]

[--persontrips] [--persontrip.transfer.car-walk CARWALKMODE] [--persontrip.walkfactor FLOAT]

[--persontrip.walk-opposite-factor FLOAT] [--from-stops FROMSTOPS] [--to-stops TOSTOPS]

[--prefix TRIPPREFIX] [-t TRIPATTRS] [--fringe-start-attributes FRINGEATTRS]

[--vehicle-class VEHICLE_CLASS] [--random-departpos] [--random-arrivalpos] [--junction-taz] [-l]

[-L] [--edge-param EDGEPARAM] [--speed-exponent FLOAT] [--fringe-speed-exponent FLOAT]

[--angle ANGLE] [--angle-factor ANGLE_WEIGHT] [--random-factor RANDOMFACTOR]

[--fringe-factor FRINGE_FACTOR] [--fringe-threshold FRINGE_THRESHOLD] [--allow-fringe]

[--allow-fringe.min-length ALLOW_FRINGE_MIN_LENGTH] [--fringe-junctions] [--vclass VCLASS]

[--via-edge-types VIAEDGETYPES] [--allow-roundabouts] [-s SEED] [--random]

[--min-distance FLOAT] [--min-distance.fringe FLOAT] [--max-distance FLOAT] [-i INTERMEDIATE]

[--jtrrouter] [--maxtries MAXTRIES] [--remove-loops]

[--random-routing-factor RANDOMROUTINGFACTOR] [--validate] [-v] [-b BEGIN] [-e END]

[-p FLOAT [FLOAT ...] | --insertion-rate FLOAT [FLOAT ...] | --insertion-density FLOAT

[FLOAT ...]] [--flows FLOWS] [--random-depart] [--binomial N]

randomTrips.py: error: the following arguments are required: -n/--net-file

Hey, I’m about to finish the second year of my CS bachelor, and I am interested in starting a summer project. Games like Rimworld and Dwarf fortress really interest me, games that feel alive, like they could go on without you in a sense. I would love to try my hand at making a very VERY simplified version of DF (as I know how complex it is) with my own spin on it. However I am unsure of where to begin.

I have some experience with C and C++, which I think could do the job along with something like SDL for simple graphics like DF. I would prefer only using C as I am not a big fan of C++. Would this be a good start?

And if anyone has any experience with this genre of gamedev, could you point me in these direction of some useful resources like books or websites. If you have any tips or suggestions i would love to hear them as well!

OpenSIMPLY is free simulation software for modeling in Delphi, Lazarus and Free Pascal.

Free download: opensimply.org

Hello, I'm currently studying Industrial Engineering. I need help on fixing a problem on my arena simulation model. The model is actually already finished and it runs fine, it consists of advanced process and advanced transfer modules. But everytime you close the file then reopens it I keep getting the error message \"Module name must be unique.\" which for some reason in the station data page station 3 and 4 is yellowed out and I need to either delete or change the name. It keeps happening even if I run it in other devices. Any help on this? I have attached my .doe file and the problem screenshot on the link below

Link to the .doe file

UPDATE: I got it fixed by simply changing my station 3 and 4 name

Hi! I am making a series on simulating molecular water, using the Julia programming language. My background is that of computational research in micromagnetics, so I thought this molecular dynamics stuff would be a fun new thing to try. I don't have a whole lot of youtube-presenting experience as you can maybe observe, but I hope any of you might enjoy this/find this interesting: https://www.youtube.com/watch?v=FxLs_ifu23U&list=PLiz3ZHIQEYQUqKWSpNreEeHvqUFvsHvo_

Hello Everyone,

im working on a Pulsed Laser Deposition setup. In this setup, a laser shoots (at a variable rate) on a target material (the rectangle shaped object at the bottom), that is then deposited (in some kind of profile, as indicated by the transparent cone) on the material on the opposite side of the target. The material on which i deposit is a tape wound around a cylinder, which is rotating at a variable rate.

In addition, the position of the target can be moved along the cylinders main axis.

The image below was created in Fusion360, to illustrate the system. Now I would like to write a code that simulates my deposition process, to predict how much material was deposited at which point of the tape.

Can someone suggest me some good starting points? Do you know libraries or programs (other programming languages are okay) suitable for this job? While I could try programming the system, I am seeking for a way to visualize the process at the same time to have a visual feedback of my calculations, as the parameters may be changed programatically during runtime.

Best Regards

MrHTSC

A simplified model of the experimental setup.

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I am trying to decide learning either Simul8 or Simio for conducting a simulation on systems. Which one of these 2 softwares will be the least demanding on my laptop.

Any other alternatives that are easy to learn and translate ideas quicker and get high level data to explore whether certain projects are worth considering for further analysis.

Hi everyone. I am receiving this error every time my simulation run is completed and i click to see the results. I am performing 200 number of replication. Would be grateful if anyone could help. thanks

I've created code in python to simulate particles and first the goal was to obtain brownian motion, meaning a plot of mean square displacement versus time gives a straight line. However I'm getting an exponent of 1.07 rather than 1.00. Meaning not straight. It is consistent even when I increase run time, change particle size, space size, velocity. I'm not sure what it could be, because when I look at a visualization of my simulation the particles behave completely normal. Any ideas?

Does anyone know how to simulate stock levels in Simul8? I'm essentially trying to model the kitchen of a fast food outlet. I want to set a stock level for fries. When this level falls below a certain limit, I want a new activity 'peeling and cutting potatoes' to become active. In this circumstance I also need one member of staff to switch from a floating resource to a dedicated resource for this activity, until the stock level is replenished to a required threshold. Any help would be much appreciated.

Tokenomics: how agents behave when faced with incentives and disincentives presented by crypto tokens.