About SDI
Simulation Dynamics, Inc.: building models since 1990
We are a simulation and analytics firm. We build models of lines, plants and supply chains, and the apps that let your own people run them. We are privately held and 100% American owned.
Trusted by 300+ organizations since the early 1990s
Our history
From bulk flow simulation to decision apps
Andy Siprelle left an industrial engineering job at ALCOA in 1990 to start SDI. That year he created bulk flow simulation, a rate-based way to model high-speed and bulk lines that later became known as discrete rate simulation.
SDI adopted Extend (now ExtendSim) early and worked closely with its makers at Imagine That. With his partner David Parsons, Andy built the SDI Industry libraries, a database library and Supply Chain Builder, and SDI completed hundreds of projects on lines, plants and supply chains. Andy also wrote the original ExtendSim training course.
In the 2000s, clients who owned Siemens Plant Simulation asked us to work in it. They paid for our training, and more than 50 projects followed.
Then came VINLogic. A logistics model that took 6 hours to run was rebuilt in .NET to run in 20 minutes, and its client used it for more than 10 years. It taught us that the lasting value is in apps built on models, not in the models alone. Today apps we built are used by more than 10,000 people a day.
- 1990
SDI founded
Andy Siprelle creates bulk flow simulation, later called discrete rate.
- 1995
First WSC paper
"Modeling a Bulk Manufacturing System Using Extend," Siprelle and Parsons. All papers.
- 1990s
ExtendSim libraries
SDI Industry, the database library and Supply Chain Builder. The first official ExtendSim training.
- 2000s
Plant Simulation
At clients' request. 50+ projects over the next 15 years.
- 2000s
VINLogic
6 hours to 20 minutes in .NET, and the start of our model-based apps.
- 2010s
Apps at scale
A production-loss app for a global CPG manufacturer, and the development team to run it.
- 2024
ChiAha spinoff
Product work moves to ChiAha. SDI stays focused on client projects.
Tool agnostic
We don't sell software
We pick the tool that fits the question, or build the tool in house, and we know ExtendSim and Plant Simulation from the inside.
2024
Why we spun off ChiAha
Running a services firm and a products company under one roof is hard to do well. So products went to ChiAha, and SDI kept consulting.
Ownership
100% American owned
Privately held and independent for 35+ years, with direct access to the people who run the company.
The team
The people of SDI
Engineers who spent careers in consumer packaged goods plants, alongside operations researchers, data scientists and .NET developers.
Andy Siprelle
Owner and founder
Industrial engineer (Virginia Tech) who founded SDI in 1990 and created discrete rate simulation. He has led every move from ExtendSim to Plant Simulation to .NET apps.
Amber Siprelle
ChiAha co-founder and SDI managing director
Operations researcher (MS, University of Tennessee) in simulation and optimization since 1996. She led SDI's ExtendSim training for many years.
Simulation Group
Bob Matthews
Simulation Group leader
Leads our Plant Simulation work after a career in reliability, material handling automation and MES.
Kenneth Nadel
Modeling engineer
Spencer Klagstad
Modeling engineer
Enterprise Group
Jeff Holland
Enterprise Group leader
Former global director of reliability engineering; runs product management for our large apps.
Michael Dorsey
Senior applications manager
John Howell
Application manager
Matthew Thal
Full stack engineer
Yangbee Thao
Full stack engineer
Peter Au-Yeung
Developer
Innovation Group
Bill Tarlton
Innovation Group leader
Chemical engineer with decades in supply chain strategy, network design and inventory optimization.
Mathias Brandewinder
Technical lead
Former F# Software Foundation board member and author of Machine Learning Projects for .NET Developers.
Alex Baker
Head of data science
Luke Schwarzentraub
Project manager
Luke Limpert
ML modeling engineer
Grant Young
F# developer
Chris Feldman
Innovation Group
Brian Jacob
Business development
Foundations
People who built SDI
David Parsons
Co-founder (retired)
Co-created SDI's ExtendSim database library and Supply Chain Builder, and co-wrote our first WSC paper. He retired in 2010 and worked with us until 2018. His books.
Michael Denzien
First CTO (retired 2022)
Brought C# to SDI, which made the .NET rebuild of VINLogic and every app since possible.
Robin Clark
Former training and development leader
Led our ExtendSim training from 2002 to 2008 and developed its course material.
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