Enlighten uses some geometric operations based on the examples from Real-Time Collision Detection by Christer Ericson, published by Morgan Kaufmann Publishers, (c) 2005 Elsevier Inc. This software has an open license, which is reproduced from the book text below.

Software License Agreement

This Software License Agreement is a legal agreement between the Author and any person or legal entity using or accepting any software governed by this Agreement. The software is available on the CD-ROM in the Book, Real-Time Collision Detection, which is published by Morgan Kaufmann Publishers. "The software" is comprised of all code (fragments and pseudocode) presented in the book. No additional files are on the CD-ROM.

By installing, copying, or otherwise using the software, you agree to by bound by the terms of this Agreement.

The parties agree as follows:

1. Grant of License: We grant you a nonexclusive license to use the software for any purpose, commercial or non-commercial, as long as the following credit is included identifying the original source of the software: "from Real-Time Collision Detection by Christer Ericson, published by Morgan Kaufmann Publishers, © 2005 Elsevier Inc".

2. Disclaimer of Warranty: We make no warranties at all. The software is transferred to you on an "as is" basis. You use the software at your own peril. You assume all risk of loss for all claims or controversies, now existing or hereafter, arising out of use of the software. We shall have no liability based on a claim that your use or combination of the software with products or data not supplied by us infringes any patent, copyright, or proprietary right. All other warranties, expressed or implied, including, without limitation, any warranty of merchantability or fitness for a particular purpose are hereby excluded.

3. Limitation of Liability: We will have no liability for special, incidental or consequential damages even if advised of the possibility of such damages. We will not be liable for any other damages or loss in any way connected with the software.