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License Agreement (EULA)

Last updated: November 4, 2025

This License Agreement ("Agreement") governs your use of the PISTON engine simulation software ("Software") and the pistonsim.com website ("Website"), both provided by Piston LLC ("Company," "we," "us," or "our"). By installing, accessing, or using the Software or Website, you agree to be bound by the terms of this Agreement.

This Agreement works together with our Terms of Service and Privacy Policy. In case of conflict, the more specific terms in this License Agreement shall control for matters relating to intellectual property and licensing.

PLEASE READ THIS AGREEMENT CAREFULLY. If you do not agree to these terms, do not install, access, or use the Software or Website.

1. Grant of License - PISTON Software

Subject to your compliance with this Agreement, Piston LLC grants you a limited, non-exclusive, non-transferable, revocable license to install and use the PISTON Software for your personal or internal business purposes during the alpha evaluation period.

1.1 Alpha Evaluation License

During the alpha phase, the Software is provided free of charge as an evaluation version. This license allows you to:

  • Install and use the Software on devices you own or control
  • Use the Software for personal projects and internal business purposes
  • Create, modify, and export engine configurations and simulation data
  • Evaluate the Software's capabilities and provide feedback

1.2 Commercial Use During Alpha

You may use the Software for commercial purposes during the alpha phase at no charge. However, following the alpha period, commercial use may require a paid commercial license. We will provide at least 30 days' advance notice before requiring payment for commercial use.

Commercial use means using the Software in connection with a business, revenue-generating activity, or professional services for which you receive compensation.

2. License Restrictions

You expressly agree NOT to:

  • Redistribute: Copy, distribute, sublicense, sell, rent, lease, or lend the Software to any third party
  • Modify Core Software: Reverse engineer, decompile, disassemble, or attempt to derive the source code of the Software
  • Create Derivative Works: Modify, adapt, translate, or create derivative works based on the Software
  • Remove Notices: Remove, alter, or obscure any copyright, trademark, or proprietary rights notices
  • Circumvent Protection: Attempt to disable, bypass, or circumvent any security features or license enforcement mechanisms
  • Compete: Use the Software to develop competing engine simulation software or services
  • Benchmark Publicly: Publish or disclose performance benchmarks or analysis of the Software without our prior written consent

Note: You may customize engine configurations, create simulation parameters, and modify settings within the Software's intended functionality for your own use. This restriction applies to modifying the Software's code, algorithms, or core functionality.

3. Intellectual Property Ownership

3.1 Software Ownership

The PISTON Software, including all source code, object code, algorithms, thermodynamic models, user interfaces, documentation, and related materials, is the exclusive property of Piston LLC and is protected by United States and international copyright, patent, trademark, and trade secret laws.

All rights not expressly granted in this Agreement are reserved by Piston LLC. This license does not transfer ownership of the Software to you; you are merely granted a limited right to use it under the terms herein.

3.2 Website and Content

All content on the pistonsim.com Website, including but not limited to text, graphics, logos, images, videos, designs, and the overall "look and feel," is owned by Piston LLC and protected by copyright and other intellectual property laws.

Permitted Use: You may view, print, and download Website content solely for your personal, non-commercial reference. You may not:

  • Reproduce, republish, or redistribute Website content
  • Use Website content for commercial purposes without written permission
  • Create derivative works based on Website content
  • Frame or mirror any portion of the Website

4. Your Data and Configurations

You Own Your Data: You retain all rights, title, and interest in and to the engine configurations, simulation parameters, output data, and results ("User Data") that you create using the Software.

You May:

  • Export and share your User Data in any format provided by the Software
  • Use your simulation results for any lawful purpose
  • Publish, present, or disclose your engine designs and simulation outcomes
  • Store backups of your User Data

Limited License to Us: By using the Software, you grant Piston LLC a limited, non-exclusive license to process your User Data solely for the purpose of:

  • Enabling the Software to function (e.g., running simulations, storing configurations locally)
  • Improving our thermodynamic models using anonymized, aggregated data (we will never disclose your specific configurations or identifying information)

5. Trademarks

PISTON and the PISTON logo are trademarks or registered trademarks of Piston LLC. All other trademarks, service marks, and trade names referenced on the Website or in the Software are the property of their respective owners.

Trademark Usage: You may refer to PISTON by name when discussing or describing the Software (e.g., "simulated using PISTON"), but you may not:

  • Use our trademarks in a way that suggests endorsement or affiliation without permission
  • Register domain names, social media handles, or business names containing "PISTON" without authorization
  • Modify or combine our trademarks with other marks or designs

6. Simulation Accuracy Disclaimer

CRITICAL - PLEASE READ:

PISTON provides estimates and approximations based on thermodynamic modeling and simulation. While we validate our models against real-world dyno data and strive for accuracy, simulation results are not guaranteed outcomes.

Real-world engine performance depends on countless variables including but not limited to:

  • Manufacturing tolerances and component quality
  • Assembly precision and installation quality
  • Tuning, calibration, and ECU programming
  • Environmental factors (temperature, altitude, humidity, air quality)
  • Fuel quality, octane rating, and additives
  • Break-in procedures and engine condition
  • Dynamometer accuracy and testing methodology

PISTON IS A DESIGN AND PLANNING TOOL, NOT A SUBSTITUTE FOR PROFESSIONAL ENGINEERING ANALYSIS OR PHYSICAL TESTING.

You are solely responsible for verifying all design decisions through appropriate engineering analysis, consulting with qualified professionals, and conducting physical testing before implementing any engine configuration. We are not liable for any damages, losses, or consequences resulting from your use of simulation data.

7. Third-Party Open Source Components

The Software and Website may incorporate or be built using third-party open source software components. These components are licensed under their respective open source licenses, which may include:

  • React - MIT License (Facebook, Inc.)
  • Next.js - MIT License (Vercel, Inc.)
  • Tailwind CSS - MIT License (Tailwind Labs, Inc.)
  • Framer Motion - MIT License (Framer B.V.)
  • React Icons - MIT License (Various Contributors)

The licenses for these third-party components are available in the Software's documentation or source repository (when applicable). Your use of these components is governed by their respective licenses, not this Agreement.

Acknowledgment: We are grateful to the open source community for their contributions, which enable us to build PISTON.

8. Updates and Modifications

Software Updates: During the alpha phase, we may release updates, patches, bug fixes, or new versions of the Software. You are not obligated to install updates, but we strongly recommend doing so for improved performance, accuracy, and security.

Updates may introduce new features, remove existing features, or change functionality. Alpha software is inherently unstable and subject to frequent changes.

Automatic Updates: The Software may check for and notify you of available updates. We do not automatically install updates without your consent during the alpha phase.

9. Support and Maintenance

Alpha Support: As alpha software, PISTON is provided with limited support. We may offer:

  • Bug reports and issue tracking
  • Community forums or discussion channels
  • Email support for critical issues ([email protected])
  • Documentation and user guides

No Guarantee of Support: We do not guarantee response times, bug fixes, or resolution of issues during the alpha phase. Support is provided on a best-effort basis.

Feedback: We encourage you to provide feedback, report bugs, and suggest features. While we appreciate your input, we are not obligated to implement any suggestions or fix reported issues.

10. Termination

Your Right to Terminate: You may terminate this Agreement at any time by uninstalling the Software and ceasing to use the Website.

Our Right to Terminate: We reserve the right to terminate or suspend your license immediately, with or without notice, if:

  • You violate any term of this Agreement
  • You engage in conduct that harms Piston LLC, other users, or third parties
  • We discontinue the alpha program or decide to cease offering the Software (we will provide reasonable notice if commercially feasible)

Effect of Termination: Upon termination, you must immediately cease all use of the Software and Website, uninstall the Software, and delete all copies. Your User Data remains yours and is not affected by termination. Sections of this Agreement that by their nature should survive (including disclaimers, limitation of liability, and intellectual property provisions) continue in effect.

11. Warranty Disclaimer

THE SOFTWARE AND WEBSITE ARE PROVIDED "AS IS" AND "AS AVAILABLE" WITHOUT WARRANTIES OF ANY KIND, WHETHER EXPRESS, IMPLIED, OR STATUTORY.

TO THE FULLEST EXTENT PERMITTED BY LAW, PISTON LLC DISCLAIMS ALL WARRANTIES, INCLUDING BUT NOT LIMITED TO:

  • Merchantability: We do not warrant that the Software is suitable for any particular market or purpose
  • Fitness for a Particular Purpose: We do not guarantee the Software will meet your specific needs or requirements
  • Accuracy: We do not warrant the accuracy, completeness, or reliability of simulation results
  • Non-Infringement: We do not warrant that your use will not infringe third-party rights
  • Uninterrupted Operation: We do not guarantee the Software will be error-free, uninterrupted, or free from bugs
  • Security: We do not warrant that the Software is free from viruses, malware, or security vulnerabilities

Some jurisdictions do not allow the exclusion of implied warranties, so the above exclusions may not apply to you. You may have other rights that vary by jurisdiction.

12. Limitation of Liability

TO THE MAXIMUM EXTENT PERMITTED BY LAW, IN NO EVENT SHALL PISTON LLC, ITS OFFICERS, DIRECTORS, EMPLOYEES, CONTRACTORS, OR AGENTS BE LIABLE FOR ANY:

  • Indirect, Incidental, Special, Consequential, or Punitive Damages
  • Loss of Profits, Revenue, Business Opportunities, or Goodwill
  • Loss of Data, Information, or Configurations
  • Cost of Substitute Goods or Services
  • Business Interruption or Downtime
  • Engine Damage, Vehicle Damage, or Property Damage
  • Personal Injury or Death

ARISING OUT OF OR RELATED TO THIS AGREEMENT, THE SOFTWARE, OR THE WEBSITE, WHETHER BASED ON WARRANTY, CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY, OR ANY OTHER LEGAL THEORY, EVEN IF WE HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

TO THE MAXIMUM EXTENT PERMITTED BY LAW, OUR TOTAL LIABILITY FOR ALL CLAIMS SHALL NOT EXCEED THE AMOUNT YOU PAID TO US FOR THE SOFTWARE IN THE TWELVE (12) MONTHS PRECEDING THE CLAIM. DURING THE ALPHA PHASE, SINCE THE SOFTWARE IS FREE, THIS AMOUNT IS ZERO ($0).

13. Changes to This Agreement

We reserve the right to modify this License Agreement at any time. When we make changes, we will:

  • Update the "Last Updated" date at the top of this page
  • Provide notice of material changes via email or in-app notification
  • Post the revised Agreement on our Website

Your continued use of the Software or Website after changes are posted constitutes your acceptance of the modified Agreement. If you do not agree to the modified terms, you must stop using the Software and Website.

Material Changes: For changes that materially affect your rights (such as pricing, license restrictions, or liability), we will provide at least 30 days' advance notice before the changes take effect.

14. Governing Law

This Agreement shall be governed by and construed in accordance with the laws of the State of Nevada, United States, without regard to its conflict of law principles.

Any legal action or proceeding arising out of or relating to this Agreement shall be brought exclusively in the federal or state courts located in Nevada, and you consent to the personal jurisdiction of such courts.

15. Contact Information

If you have questions about this License Agreement or wish to request permissions beyond the scope of this license, please contact us:

Piston LLC
Email: [email protected]
Website: https://pistonsim.com

License in Plain English

Here's the summary:

  • Free during alpha: Use PISTON for free (personal and commercial) while we're in alpha testing
  • Don't redistribute: You can't share, sell, or give the software to others
  • Don't modify the code: You can't reverse engineer or change the software itself (but you can customize engine configs)
  • You own your data: All engine designs and simulation results you create are yours
  • Use at your own risk: Simulations are estimates - verify everything before building
  • No warranties: Alpha software is provided as-is with bugs and no guarantees
  • Website content is copyrighted: You can view our site but can't copy/republish the content

Legal Notice: This License Agreement is a legally binding contract between you and Piston LLC. While we have made every effort to ensure accuracy and completeness, we recommend consulting with a legal professional if you have questions about your rights and obligations under this Agreement.