SD/FAST provides physically-based simulation of mechanical systems by taking a short description of an articulated system of rigid bodies (bodies connected by joints) and deriving the full nonlinear equations of motion for that system.The equations are then output as C or Fortran source code, which can be compiled and linked into any simulation or animation environment. The symbolic derivation of the equations provides the fastest possible simulations. Many substantial systems can be executed in real time on modest computers.

SD/FAST was developed by Michael Sherman and Dan Rosenthal of Symbolic Dynamics and has been distributed by PTC since January 2001. With over 31,000 customers worldwide, PTC is the leader in providing product development solutions for manufacturing. PTC provides the solutions and experience to help manufacturers get better products to market in less time. For more information, visit 


Current Applications

Applied Animation links

SD/FAST-based codes

SD/FAST is industrial-grade code in daily use at thousands of sites worldwide. Some typical application areas:

These are links to some of the places which use SD/FAST as their dynamics engine for physically-based animation:

SD/FAST is the behind-the-scenes dynamics engine inside  these widely used programs:


  • Physically-based animation
  • Mechanism simulation for engineering
  • Aerospace simulation
  • Robotics
  • Real-time hardware-in-the-loop and man-in-the-loop simulation
  • Biomechanical simulation
  • Games

  • Pro/Mechanica Motion
  • SIMM (Software for Interactive Musculoskeletal Modeling) from MusculoGraphics, Inc.

Contact Information

General Inquiries

Licensing & Sales

Mark Fischer

Grant Perry

Free Evaluation

To give SD/FAST a try, download the software from either of the links below. Once you have installed the software and examined the included user manual, send email to requesting an evaluation license.

Download SD/FAST

Zip File (.zip)