Terms of Use

1Agreement to these terms

These Terms of Use (“Terms”) are a legal agreement between you and Zydeno, the developer of Chamferline (“we”, “us”). They apply to the Chamferline app for Android, its updates and everything it shows or produces (together, “the app”). By installing, opening or using the app you accept these Terms. If you do not accept them, do not use the app and uninstall it.

The Privacy Policy explains how the app handles data and forms part of these Terms. If we offer optional features under additional terms in the future, for example paid features, those terms will be shown to you before you accept them and will apply together with these Terms.

You must be old enough to enter into a binding contract where you live, or use the app with the consent and supervision of a parent or guardian who accepts these Terms for you. If you use the app for an organisation, you confirm that you may accept these Terms on its behalf; the consumer-protection provisions of these Terms apply only to consumers.

2What Chamferline provides

Chamferline is an offline 3D modeler for 3D printing. You can build parts from boxes, cylinders, text and templates, cut holes, type exact sizes, align and measure, check a part for printing problems (overhangs, thin walls, bridges, islands, size against your plate), fit mating parts with clearances for your printer and material, open and repair STL, 3MF and OBJ files, keep versions, and export STL, 3MF, OBJ or a backup archive. Templates cover simple household and workshop parts such as boxes with lids, hooks, knobs, plates and fasteners.

Features depend on the version you install and on your phone; for example, very large models can exceed what a phone can hold. Descriptions of possible future features do not make them available in the current version. Chamferline does not slice models, control or connect to a printer, or produce machine instructions.

3Not professional advice; no safety-critical use

The app is a tool to help you plan and calculate. It does not give professional, engineering, legal or other expert advice, and using it does not create a professional relationship with us. You remain responsible for your inputs, for how you interpret the results and for what you decide to do.

Do not use the app as the only basis for a decision where an error could cause death, personal injury, damage to property or the environment, or legal or financial loss, and do not use it in a safety-critical system, in an emergency or to control equipment. Chamferline is a modeling tool. Its fit, clearance, strength-related and print-check results are guidance, not engineering certification, and it performs no structural, thermal, electrical, food-safety or regulatory analysis. It must not be used to design firearms, ammunition, weapon parts, explosives or other items that are unlawful where you live (see the section on items you must not make).

4Licence to use the app

Subject to these Terms, we grant you a limited, personal, revocable, non-exclusive, non-transferable and non-sublicensable licence to download, install and use the app on Android devices you own or control, for your own purposes. The app is licensed to you, not sold.

Except where these Terms, an open-source licence or mandatory law allow it (for example decompiling for interoperability where the law permits), you may not: copy, modify, translate or create derivative works of the app; decompile, disassemble or reverse-engineer it; rent, lend, sell, sublicense, distribute or publish it, or make it available for use by others over a network; remove or change any copyright, trademark or legal notice; or get around any technical limit of the app, including any future purchase, licence or advertising mechanism.

Open-source components and fonts in the app are licensed under their own licences, listed in the app under About → Open-source licenses. Those licences prevail for those components, and nothing in these Terms limits the rights they give you.

5Sizes, fit and checks are guidance

Dimensions you type are applied by the app as entered, but everything the app derives from them is an estimate: mass, filament length, material cost and print time; fit classes and clearances; thread, insert and hole sizes; overhang, wall-thickness, bridge and island findings; the guessed unit of an imported file; and the result of an automatic repair or orientation. These results depend on assumptions the app cannot see, such as your printer’s calibration, nozzle, temperatures, material batch, slicer settings, humidity and wear.

A clearance or fit class from your clearance profile is a starting value learned from the results you enter, not a tolerance guarantee. A part that the app marks as ready to print may still fail to print, or fail in use; a part with findings may print well. Thread, hole and insert sizes follow published nominal values entered by Zydeno; they are not copies of any standard, and the app does not certify that a part complies with, or is compatible with, any standard, product or regulation.

6Printed parts: your responsibility

Printed plastic can be brittle, can creep or soften with heat and sunlight, can have weak layer bonds and can shatter. Do not use parts you make with the app where their failure could injure someone or cause damage: for example to support people or heavy loads, in vehicles, aircraft, ladders, climbing or lifting gear, pressure or heated systems, mains-powered or other electrical equipment, safety, protective or medical equipment, or in products for infants and children. Do not assume a part is food-safe or suitable for contact with skin.

Test before you rely on a part, use a test piece or the calibration coupon to learn how your printer fits, and have anything safety-relevant designed and checked by a qualified engineer. Operating a 3D printer involves hot surfaces, moving parts, fumes and fire risk; follow the printer maker’s instructions and never leave a printer running unattended where that is unsafe. Nothing in the app is advice on operating a printer.

7Items you must not make

You must not use Chamferline to design, modify or prepare for manufacture firearms, firearm frames or receivers, ammunition, parts or accessories of weapons (including devices that convert or modify how a weapon fires), explosives, or any other item whose making, possession or distribution is unlawful where you live or where the item will be used. The app provides no templates, instructions or library for such items and does not check designs for them.

You are responsible for knowing and complying with the laws that apply to what you make and share, including product-safety, import and export, intellectual-property and weapons laws. We may refuse support to anyone who uses the app in breach of this section, and your licence to use the app ends automatically if you do.

8Files, formats and your content

You keep the rights you hold in your own designs. Saving, exporting or sharing a part with Chamferline does not transfer ownership of it to Zydeno, and we claim no rights in the files you make. The shapes you create with the app’s tools and templates, and 3D text you make with the bundled fonts, are yours to use under the law that applies to you.

Only import, edit, print, sell or share files that you own or are allowed to use. Many models found online are licensed with conditions or for personal use only, and editing or repairing a model does not give you rights in it. We do not check the files you open and are not responsible for the content of files you import, export or receive.

Import and repair can change a file: the app may close holes, flip faces, merge points, drop degenerate triangles, simplify to fit your phone or guess units. Check the result before you print it and keep your original file. Other programs may read an exported file differently, and the app cannot promise that a file opens identically in every slicer or viewer. 3MF files follow the publicly available 3MF Core Specification; STL and OBJ are informal formats.

9Local data, deletion and backups

Your data stays on your phone unless you choose to export or share it. There is no developer account, no server copy and no automatic cloud backup. Delete all removes your parts, versions and settings after you confirm, and deleting a part or version is permanent once the undo time has passed. Imports add parts to what is already on the phone; export first if you want a copy. Exported files are ordinary, unencrypted files and are your responsibility; copies saved outside the app are not removed by Delete all. If a phone is lost, damaged or its storage is cleared, your work cannot be recovered by us. See the Privacy Policy for details.

10Fonts, standards and open-source components

The app bundles the Akt typeface (© 2024 The Akt Project Authors), the Iosevka Charon Mono typeface (© 2025 The Iosevka Project authors) and Noto Sans fonts for Arabic, Hebrew, Devanagari and Thai (© The Noto Project Authors), all under the SIL Open Font License 1.1. Its modeling engine uses the Manifold geometry library (© The Manifold Authors, Apache License 2.0), with components under the MIT and zlib licences, and the Clipper2 polygon library (© Angus Johnson, Boost Software License 1.0). The app also uses AndroidX and Kotlin libraries under the Apache License 2.0. The licence texts and notices are available in the app under About, Sources and licences, and work offline.

The OFL does not apply to the models you make: a part you create with 3D text is your own work, not a font. The sounds, icons, templates, drawings and help text in the app were created by Zydeno. Open-source licences prevail for the components they cover, and these Terms do not grant permission to resell a font file or library contrary to its own licence.

Printer, filament and other product names in the app’s presets identify products only, belong to their owners and are used for identification. Chamferline is not affiliated with any printer maker; printer sizes are nominal values compiled from public information and may differ from your machine. The app’s thread and hole values follow nominal sizes published in standards such as ISO 261, ISO 262, ISO 273 and ASME B1.1, which are copyrighted by their publishers and are not reproduced here. Android, Google Play, 3MF and other third-party names identify their respective products and do not imply endorsement.

11Acceptable use

Use the app lawfully and considerately. Do not present output of the app as certified, tested or approved, do not rely on it as the only basis for a part that matters, and do not use it to infringe anyone’s intellectual property or to make items covered by the section on items you must not make.

12Our materials

The app, its brand, interface, artwork, sounds, templates and help text are protected by intellectual-property law. These Terms do not grant a right to extract and redistribute them as a separate product.

13Price, payments, ads and future paid features

Current version. The current version of Chamferline is provided free of charge, without ads and without in-app purchases or subscriptions. This describes the current version only. It is not a promise that the app, or any feature of it, will remain free of charge or free of ads.

Possible changes. We may at any time introduce advertising; offer paid features, in-app purchases, subscriptions or a paid edition; change which features are free; and set or change prices. Features that are free today may require payment in a future version. We will describe such changes in the store listing and release notes, and in the Privacy Policy where they affect data.

Purchases. Any purchase will be made through Google Play and processed by Google under the Google Play Terms of Service and its payment policies. Prices are shown in Google Play before you buy, including taxes where applicable. Subscriptions renew automatically until you cancel them in Google Play; cancelling stops future renewals. Refunds follow Google Play’s refund policies and your mandatory consumer rights, such as the right of withdrawal in the EU and the UK. Where you ask for immediate access to digital content during a withdrawal period, you may lose that right to the extent the law allows, and you will be asked to confirm this before you buy. You are charged only if you choose to buy something.

Ads. If the app shows ads, they are supplied by third parties. We are not responsible for the content of ads or for the products and services advertised, and any dealings with advertisers are between you and them.

Price changes. We may change prices for future purchases at any time. For an active subscription, we will announce a price increase as Google Play and the law require, and you can cancel before it applies.

14Disclaimer of warranties

The app is provided “as is” and “as available”. Sizes, fits, clearances, checks, estimates, repairs, converted units and exported files can be wrong. We do not promise that a part will print, fit, hold, last or be safe, that a check finds every problem, that an estimate of mass, cost or time is accurate, that an imported file is repaired correctly or opens identically in every program, that the app handles any particular model size on your phone, or that lost or deleted work can be recovered.

15Limitation of liability

To the extent the law permits, we are not responsible for any loss or harm arising from the use of parts you design or print with the app or from errors in its results, including failed, wasted or misfitting prints; wasted filament, printer time, energy and materials; damage to a printer, tool or other equipment; fire, burns, fumes or other harm from operating a printer; breakage or failure of printed parts and any resulting injury, death or property damage; products you make or sell to others and claims about them; infringement by files you import or share; lost, corrupted or deleted work; or disclosure through a destination you select. The limitations and mandatory exceptions below govern this clause.

16Your rights as a consumer

If you use the app as a consumer, you benefit from the mandatory consumer-protection rules of the country where you live, and nothing in these Terms affects them. In particular:

• EU and EEA: your statutory rights, including those on the conformity of digital content and digital services under the national rules implementing Directive (EU) 2019/770 where they apply, and mandatory product-liability rules, remain unaffected.
• United Kingdom: your statutory rights, including under the Consumer Rights Act 2015, remain unaffected.
• Australia: our services come with guarantees that cannot be excluded under the Australian Consumer Law. Where the law allows us to limit our liability for failing to meet a consumer guarantee for services that are not of a kind ordinarily acquired for personal, domestic or household use, our liability is limited to supplying the services again or paying the cost of having them supplied again.
• New Zealand: if you acquire the app for business purposes, you agree that the Consumer Guarantees Act 1993 does not apply, to the extent the law permits.
• United States and Canada: some states and provinces do not allow the exclusion of implied warranties or the limitation of incidental or consequential damages, so some of the exclusions above may not apply to you. In Québec, the mandatory provisions of the Consumer Protection Act apply.

17Indemnity

To the extent permitted by law, you agree to indemnify and hold harmless the developer against claims, liabilities, damages, losses and reasonable costs, including reasonable legal fees, brought by third parties and arising out of (a) the parts you design, print, sell, give or provide to others, and the files you import, export or share, including files whose rights you do not hold, (b) your breach of these Terms, (c) your violation of any law or of the rights of others, or (d) output of the app that you provide to another person, such as a client or employer. This does not apply to the extent a claim is caused by our own breach of these Terms or our negligence, or where local consumer law does not allow it.

18Changes, availability and termination

To the extent the law allows, we may change, update, add or remove features, change data sources, and suspend or discontinue the app, in whole or in part or in any country, at any time. We are not obliged to provide updates, maintenance or support, except where mandatory consumer law requires updates to keep the app in conformity.

You may stop using the app at any time by uninstalling it. Your licence ends automatically if you materially breach these Terms, and we may end or suspend it where the law requires. When it ends, you must stop using the app and uninstall it. Your data stays on your device under your control, so export what you need first.

Provisions that by their nature should continue after these Terms end continue to apply, including those on intellectual property, disclaimers, limitation of liability, indemnity, governing law and general provisions.

19Google Play

You obtain the app through Google Play. Your download, and any purchase you make, is also governed by the Google Play Terms of Service and Google’s policies. Where these Terms conflict with Google Play’s terms on the distribution, billing, refunds or licensing of apps obtained from Google Play, Google Play’s terms prevail to the extent of that conflict.

These Terms are between you and the developer only, not Google. Google is not responsible for the app or its content and has no obligation to provide maintenance or support for it. Android and Google Play are trademarks of Google LLC.

20Governing law and disputes

These Terms, and any dispute or claim arising out of or in connection with them or the app, including non-contractual disputes, are governed by the law of the country in which the developer is established, without regard to its conflict-of-laws rules. The United Nations Convention on Contracts for the International Sale of Goods does not apply.

The courts competent for the place where the developer is established have jurisdiction. If you are a consumer, you keep the protection of the mandatory provisions of the law of your country of residence, and you may bring proceedings in the courts of that country where that law allows it.

Before starting formal proceedings, please write to [email protected] and give us at least 30 days to try to resolve the issue informally. This does not affect any time limit that applies to you by law or your right to use an alternative dispute-resolution body available to consumers in your country.

21General provisions

• Entire agreement. These Terms, the Privacy Policy and any additional terms you accept for optional features are the entire agreement between you and us about the app.
• Severability. If a provision is found invalid or unenforceable, it applies to the maximum extent permitted and the rest remains in effect.
• No waiver. Not enforcing a provision is not a waiver of the right to enforce it later.
• Assignment. You may not transfer your rights or obligations under these Terms. We may transfer ours, for example together with the app to another developer; where the law requires, this will not reduce your rights as a consumer.
• Events beyond our control. We are not responsible for failure or delay caused by events beyond our reasonable control, such as outages of networks, devices or third-party services, natural disasters or acts of authorities.
• Export and sanctions. You agree to use the app in compliance with applicable export-control and sanctions laws.
• No third-party rights. No one other than you and us may enforce these Terms.
• Notices. We may give notices in the app, in its store listing or release notes, or on this page. You can send notices to [email protected].
• Language. These Terms are written in English, which is the binding version. A translation, if offered, is for convenience only, unless the law of your country requires otherwise.

22Changes to these terms

We may update these Terms, for example when we change the app, introduce ads or paid features (§13), or when the law changes. The effective date and version at the top of this page show which version applies, and the version history (§23) summarises the changes.

For material changes we give reasonable notice before they take effect, for example in the release notes or in the app. If you keep using the app after the changes take effect, you accept the updated Terms; if you do not agree, stop using the app and uninstall it. Changes do not apply to disputes that arose before they took effect.

23Version history

24Contact

• Developer: Zydeno, the developer of Chamferline on Google Play
• E-mail: [email protected]
• Website: zydeno.com

See also the Privacy Policy.