Simulation Dynamics, Inc. · Since 1990

Manufacturing and supply chain simulation, 35 years deep.

We build custom simulation models and decision apps for lines, plants, warehouses and supply chains. You see what would happen before you spend the capital or change the schedule.

Trusted by 300+ organizations since the early 1990s

$1B+in client savings from one logistics model, over more than a decade of use
35+years building simulation models for manufacturers and shippers
50+Plant Simulation projects in the last 15 years
15,000+people a day use decision apps we built from models

Tool agnostic

We don't sell software. We pick the tool that fits the question, or build the tool in house.

Some problems need a fast, rate-based model of a 1,200-bottle-a-minute line. Others need 3D animation that a plant team can walk through, or an optimizer wrapped in an app a planner runs every Monday. We have built all of these, in whatever your team already uses or in what fits best.

Three tools we know from the inside:

  • ExtendSim: 35+ years of project work, plus the libraries we built for it, including the first discrete rate (bulk flow) engine.
  • Plant Simulation: 15+ years and more than 50 projects, led by engineers who spent their careers in consumer packaged goods plants.
  • ReliaSim: the third generation of our discrete rate method, for line reliability and OEE, validated within 1% of measured OEE.

We also build and curate simulation libraries inside these tools, so your own modelers start from tested equipment blocks. When a model outgrows the tool, we rebuild it in .NET, F# or C# so it runs in minutes and your planners can use it without us.

Where the tools came from

  1. 1990

    Bulk flow simulation

    Andy Siprelle creates the rate-based method for high-speed and bulk lines, later called discrete rate simulation.

  2. 1995

    First paper, built on Extend

    "Modeling a Bulk Manufacturing System Using Extend" at the Winter Simulation Conference.

  3. 1990s

    SDI Industry libraries

    Our libraries for Extend (now ExtendSim) become the standard way to model continuous and high-speed operations.

  4. 2000s

    Plant Simulation, at customers' request

    Clients who owned Plant Simulation asked us to move with them. Fifty-plus projects followed.

  5. Today

    Models become apps

    We wrap models in decision apps, and spun off ChiAha in 2024 to build them as products.

Discrete rate simulation

The method for modeling high-speed lines started here.

A bottling line moving 1,000 containers a minute is a flow, not a queue of parts. Andy Siprelle built bulk flow simulation in 1990 to model it that way, and the idea later became discrete rate simulation, now in every major simulation package.

We have written about it at the Winter Simulation Conference since 1995, and we still use it on packaging, food and bulk-handling lines.

Bulk grain moving through a processing line

Reading list

Books by our people

Cover of Infinity Within His Grasp by David Parsons

David Parsons

Infinity Within His Grasp

A 17th-century historical novel

January 2026 · 178 pages · Paperback

David's first novel. Historical fiction set in the 1600s, it follows a young man from Boston who crosses paths with figures including John Wallis and Galileo.

Buy on Amazon
Cover of AI: Thinking Without Understanding by David Parsons

David Parsons

AI: Thinking Without Understanding

A conversation with ChatGPT

April 2025 · 276 pages · Paperback

An unedited conversation between David and ChatGPT about the strengths and weaknesses of large language models.

Buy on Amazon
Cover of Gravity by David Parsons

David Parsons

Gravity

How to weigh the sun and other gravity challenges

2019 · 175 pages · Paperback

A dialogue between David and his granddaughters, Nora Parsons and Emerson Chura-Parsons, in the style of Galileo. Starting from two facts, Earth's distance from the sun and the length of a year, they find the sun's mass with nothing beyond middle-school algebra, deriving the gravitational constant and Earth's mass along the way.

Buy on Amazon
Cover of COVID-19 by David Parsons

David Parsons

COVID-19

Anatomy of a pandemic

December 2021 · Kindle

“Like a bulldog”, he was relentless, analyzing the data and publishing his analyses each week, from the beginning to the very end. So much for “leaving it to the experts!” The book explores why the pandemic took such a twisting path, from how infection and immunity concentrated in a small share of people to what a one-month delay in early US vaccine distribution would have cost.

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Cover of Eight Principles of Effective Problem Solving by David Parsons

David Parsons

Eight Principles of Effective Problem Solving

Strategies for a world that will demand innovation

November 2012 · Paperback and Kindle

Eight principles distilled from a lifetime of successes and failures in computer simulation, project management, manufacturing, architecture, student pranks and soccer coaching, with more than forty strategies for getting past the barriers to solving problems. One case comes from SDI's own history: Plant Builder, the modeling kit we built, overdeveloped and put on the shelf.

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Cover of Educating Problem Solvers by David Parsons

David Parsons

Educating Problem Solvers

Learning the principles of effective problem solving

October 2012 · 162 pages · Kindle

David takes on the failure of traditional education to foster effective problem solving and challenges educators at all levels to embrace problem-based learning, with guidelines for parents preparing their children to be effective problem solvers.

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Cover of Machine Learning Projects for .NET Developers by Mathias Brandewinder

Mathias Brandewinder

Machine Learning Projects for .NET Developers

Hands-on machine learning projects in C# and F# (Apress, 2015)

June 2015 · 319 pages · Paperback · Apress

Build smarter .NET applications that learn from data, using simple algorithms on practical problems. Projects include an optical character recognition system built from scratch, a spam filter and a game that learns from experience, coded in Visual Studio with the machine learning logic in F#.

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Tell us your problem

What would happen if you changed it?

Describe the decision in front of you. We'll tell you whether a model can answer it, and what it would take.

  • A straight answer on whether simulation is the right tool
  • Which tool fits, even if it isn't one we use every day
  • A rough scope and timeline, before any commitment

Or book a 30-minute call.

We reply within one business day. Prefer email? info@simulationdynamics.com