DynaMo: Dynamic Motion library

The library that powers your animations

News
Introduction
Requirements
License
Documentation and Publications
Examples
Download
Installation
Links

News

September 12th, 2007.
- Even though active development and maintenance on DynaMo has stopped, all files are now archived at the http://home.iae.nl/users/starcat/dynamo/ site.
January 16th, 2004.
- A new year, and a new game that uses DynaMo. Check it out here.
June 20th, 2004.
- Fixed a small memory leak in the constraint manager, courtesy of Fèlix Casablancas, who's using Dynamo in a game of his.
May 13th, 2003.

Moved the main page and the dynamo source to my personal homepage as I don't know how long I'll retain access to the TUE web-server. Please use url http://home.iae.nl/users/starcat/dynamo/ from now on.
Januari 12th, 2003.

Fixed a bug in the large matrix code, thanks to Joanus D'Mentia for the report and fix.
March 6th, 2002.

Added the GDP code for the examples in the Ph.D. thesis to the download section.
December 16th, 2001.

Move to the new site (http://www.win.tue.nl/dynamo/ instead of http://www.win.tue.nl/~bartb/dynamo/)
Added some examples by Johan Geerlings who coupled Dynamo and Solid.
Fixed some html in this page. Thanks to Elie Accari for the heads up!
November 18th, 2001.

Fixed a bug in the code for springs and made it a bit safer, thanks to Gary R. Van Sickle.
October 18th, 2000.

Fixed two memory leaks (constraint manager / collision handling)
Thanks to Pierre Terdiman for pointing them out!
April 19nd, 2000.

Msg() method added for easier rerouting of messages
Added Vincent Harvey's GLUT render functionality for the examples.
Improved velocity term handling (see Appendix C of the Ph.D. thesis)
Januari 22nd, 2000.

Link added in the documentation section to my Ph.D. thesis, which describes the design of Dynamo.
July 26th, 1999.

Two examples added: one that extends the basic example to show how models can self-assemble using the constraints, and another which shows the use of the collision constraint.
July 20th, 1999.

The example (Direct3D version) now shows the frame rate
June 23rd, 1999.

removed some example source files which accidently had gotten into the Cpp directory in the distribution.
Fixed a few bugs (mainly related to collision handling).
June 8th, 1999.

Adjusted example (added John Nagle's OpenGL support; stability improvement)

Adjusted documentation regarding the interface to collision detection, and fixed a potential initialisation problem in the constraint manager. (thanks to Tim Mensch for pointing out the problems)
March 27th, 1999. Dynamo first put on the web

Introduction

Dynamo is a software library providing classes that takes care of the calculation of the motions of geometries moving under the influence of forces and torques and impulses. In addition, the library can also compute forces for you through the mechanism of constraints. These allow you to easily connect geometries to each other in various ways. A constraint only has to be specified once, and the Dynamo library will continually enforce it from that moment on by applying the required reaction forces. Some of the Dynamo's features are:

Full forward dynamics support for forces, torques and impulses.
Runs side-by-side with your application, and has a low-bandwidth interface communicating the newly calculated positions and orientations to your application.
Fast, tunable inverse dynamics support via constraints.
Over a dozen constraints available, including several types of hinges and a constraint for collision response calculations.
Support for controllers, activators and sensors.

Fully object oriented design, allowing for easy extension of the library by adding your own constraints and controllers via inheritance: just derive your own class from the provided constraint or controller classes by implementing a few predefined methods.

Requirements

The library is written in C++. It has been complied and tested on Sun and Silicon Graphics workstations using the standard CC compilers, and on the PC using MS Visual C++ 5.0.

License

The Dynamo library is released under the terms of the GNU Library General Public License (see the documentation).

Documentation and publications

First, some older publications, based on my work for my Masters in which I added dynamics to one of our animation programs:

May the Force be with you: this is a synopsis of the main findings of my Master's Thesis. It was written for a course in Technical Writing and Editing which I took during my time as an OOTI. It serves as a nice introduction to the field of motion dynamics, and should also be readable while skipping all the formulae-bits for those who just want an overview without too many details.

All you need is force, which I co-wrote with my supervisor C.W.A.M van Overveld, was presented at the Workshop for Computer Animation and Simulation at EuroGraphics '95 (by me). It builds upon the work I did for my Master's Thesis, but presents the problem in a more general setting which suggest the approach taken in the work below.

Using what I learned before, I restarted builing a seperate object-oriented dynamics library as the final project of the OOTI course. Here is the report describing that design:

Designing a library for constraint driven dynamics in the GDP: this is my final report of the postgraduate programme Software Technology and describes the first part part of my PhD work, which has led to the Dynamo library. Here the ideas and algorithms are presented in an Object Oriented environment, which in my opinion leads to a much more intuitive view on the subject matter.

Afterwards, I extended this library to what has become Dynamo in my Ph.D. work. The resulting thesis describing the design of Dynamo (which I defended on April 27th 2000) is now available in pdf format (1.1MB).

The library has been developed for use in a host application. For tests and demos it has been incorporated in our GDP system. Here is the documentation for both the stand-alone Dynamo library, and also for the additional functionality provided bythe GDP wrapper:

Here is the user documentation for the stand-alone Dynamo library.

Here are class interface definitions for the Looks language: the language used by the GDP.

Examples

An example is shown in the following mpeg movie which shows a sort of roller coaster. The motion in this animation is specified through the geometry of the track and the cart, a constraint that specifies that the cart is connected to the track (but can move freely along the track), a constraint that specifies that both parts of the cart are connected through a pin joint, and the specification of gravity. The system will calculate and apply reaction forces such that the two parts of the cart and the track and the cart remain connected (but the gravity will cause the cart to slide along the track).

Another example featuring a rolling bicycle is presented here.

Download

Dynamo is available for downloading as a zip file: dynamo.zip (1MB zip file)
Also available are the Looks sources of the examples in the thesis (70KB zip file)

Installation

The user documentation provides instructions on the two callback functions which need to be implemented to allow the library to communicate with your software. A make file is provided for compiling on a Sun or SGI workstation. The example which is provided shows how the library might be compiled on a PC.