# Announcing Modelica by Example

## Free Interactive Book: Modelica by Example

During Modelica'2014, I unveiled the very first public release of my new book, "Modelica by Example". Since then, the book has been available on a special site.

### Kickstarter

"Modelica by Example" started off as a Kickstarter project. As a result of the generous contributions, that project was funded. At the recent Modelica'2014 conference an "Early Access" version of the book was released.

This was a great example of a community driven project to make Modelica more accessible.

The book is distributed under a creative commons license. This means that the contents of the book an be freely redistributed (as long as it is done on a non-commercial basis and the contents of the book are not changed).

I'm also pleased to announce that there are plans for translations of the book into Spanish, Chinese and Italian (and hopefully more languages in the future).

### Free HTML Version

A free HTML version of the book is available at http://book.xogeny.com/. This book can be used by anyone interested in learning Modelica.

### Electronic Formats

I am also producing ePub and PDF versions of the book. These are available for download to those who have purchased a copy of the book. Pricing of the electronic formats is "Pay what you can". The idea here is to make the book affordable for students by allowing them to set their own price. My hope is that other people using the book for professional purposes will pay what they think the book is worth to them.

### Integrated Browser Simulation

The free HTML version of the book features "Integrated Browser Simulation". In practice, what this means is that example models from the book can be simulated directly in the browser. This allows readers to adjust parameter values given in the example models to see how the response of the example will change for different parameter values.

We will be using this same technologies in some new products we are currently working on. To learn more, sign up for the Xogeny mailing list and we'll keep you up to date on all the things we are working on.

### Early Access Version

This version is an "Early Access" version. The book is mostly complete. There are a few unfinished sections that I hope to wrap up soon. But the core material is there so anybody interested in learning Modelica can start now.

The goal of the "Early Access" version is to get this material into the hands of people who can use it as quickly as possible and to collect feedback on the book before publishing a print version of the book.

But today I'm releasing v0.3.0 of the book with the following changes since the initial public beta release (v0.2.0):

#### Enhancements

• Moved the site to book.xogeny.com with redirects from beta site.
• Lots of cleanup of annotations by @tbeu and @dietmarw
• Switched back to using MathJax (looks nicer, but requires JS)
• Updated the README to help orient people who want to contribute.
• Incorporated a bunch of excellent fixes and improvements from @mrtiller related to #42.

#### Bug Fixes

• Merged a the following pull requests from @tbeu: #143, #142, #141, #139, #137, #117 and #93
• Merged a change from @tbeu regarding a heat transfer example in the discussion on packages.
• Merged a bunch of changes from @tbeu that improve the external function examples and clean up a few other things.
• Fixed an error in the source code for the 1D heat conduction equation examples and fixed a recurring error (see issue #53) in the equations presented along with the source code.
• Fixed issue #61 which involved a misplaced annotation.
• Fixed an error in one of the Lotka-Volterra equations raised in issue #50.
• Corrected the explanation on the unit attribute raised in #59

### GitHub

The source material is available on GitHub. If you find an issue with the book, you can report it on the GitHub issue tracker or, even better, submit a pull request with a suggested fix.

### Conclusion

My goal is to provide a definitive reference for Modelica that is widely accessible and affordable. Today marks release 0.3.0 and I'll be working toward a 1.0 release that we can publish in print form.