STL VIEWER

Privacy Policy

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1. About this policy

This Privacy Policy explains how STL Viewer: 3D Print Files ("STL Viewer") handles information when you use it. STL Viewer is an Android app for opening and inspecting 3D model files: STL, OBJ (with MTL), 3MF and PLY. It works offline, needs no account, and does not ask for your name, email address, contacts, photos, camera, microphone or location.

2. Your 3D files stay on your device

When you open a file with Open file, with "Open with" in another app or from the share menu, STL Viewer reads it on your device to draw it in 3D and to work out its size, volume, surface area and filament estimate. The Measure, Section, Scale & export and Compare tools also run on your device. Your models are never uploaded, and the developer has no server that could receive them.

  • Recent files. For each file in Recent files, the app keeps on your device its name, format, file size, triangle count, dimensions, volume, the file unit you chose, when you last opened it and a small preview image.
  • Access to your files. To reopen a recent file, the app keeps Android's read permission for that one file. If another app shares a file without a lasting permission, STL Viewer keeps a private copy in its own storage (up to 200 MB in total; the oldest copies are removed first).
  • How many files are shown. Without Premium the list shows your 10 most recent files (sample models don't count). Older files stay stored on your device, hidden, and show again with Premium; with Premium the list shows them all. Removing a file from the list, or Settings → Clear recent files, deletes its entry, preview and any private copy. Your original files are never changed or deleted.
  • Exports. Models you save with Scale & export go to the place you choose in Android's file picker.
  • Sample models. The sample models are original files that the app writes to its own storage on your device.
  • Settings. Your units, filament, model color and view defaults, theme and language, together with app state such as onboarding progress, review and ad timing and your active Premium plan, are stored on your device. If Android backup is turned on, they can be part of your own device backup. Recent files, previews and private copies are excluded from backup and device transfer.

3. Advertising (Google AdMob)

If you don't have Premium, STL Viewer shows ads from Google AdMob in three places:

  • a banner at the bottom of the home screen with your recent files;
  • sometimes a full-screen ad at a natural break: when you close a model and go back to the list. Never when the app starts, never in your first session, and at most one every three minutes;
  • an optional rewarded ad that you can choose to watch to use the Measure tool once.

Apart from a rewarded ad you choose to watch, ads never appear over the 3D view while you work with a model. To deliver, measure and protect ads, Google and its ad partners may process your device's Android advertising ID, your IP address and the approximate location derived from it, device and app information, and ad interaction and diagnostic data.

Before ads load, STL Viewer uses Google's User Messaging Platform to ask for your consent, or to offer the choices privacy laws require, where those laws apply (for example in the EEA, the UK and Switzerland). You can change your choices at any time under Settings → Ad privacy choices (shown when it applies to you), and you can reset or delete your advertising ID in Android's settings. On Android versions that offer them, the ads SDK may also use Android's own ad privacy features, which you control in your device's ad privacy settings. With Premium you see no ads: the app shows no consent form and doesn't start the ads SDK.

How Google uses information from apps that use its services · Google Privacy Policy

4. Purchases (Google Play)

Premium is sold through Google Play, as a one-time purchase or as a yearly subscription that renews automatically until you cancel it in Google Play. Google Play handles the payment: STL Viewer never receives your card or other payment details. To unlock Premium, the app asks Google Play on your device which STL Viewer purchases your Google account owns, and it stores only which Premium plan is active (lifetime or yearly). Google Play gives the developer order records (such as an order number, the product, the price, the date and the country) for accounting, tax, refunds and support. Google describes how it handles your purchase in the Google Privacy Policy and the Google Play Terms of Service.

5. Ratings and reviews

After you have opened a few models, STL Viewer may show Google Play's in-app review card, at most once every 30 days and never over an ad. Your rating and review go to Google Play under your Google account; STL Viewer does not receive them and does not know whether you left one.

6. Analytics, crash reports and support emails

STL Viewer does not include analytics or crash-reporting SDKs, and the developer does not track how you use the app. If this changes in a future version, this policy will be updated before that version is released. When you choose Settings → Send feedback, your email app opens a draft that includes the app version, Android version, device model and app language so we can help you; you can edit or delete these lines before sending. We use your email only to answer you.

7. Permissions

STL Viewer asks you for no permissions while you use it. Its Android manifest declares only these, which Android grants at install:

  • Internet and network state: for ads, the consent form and Google Play purchases.
  • Advertising ID and Android's ad services (AD_ID, ACCESS_ADSERVICES_AD_ID, ACCESS_ADSERVICES_ATTRIBUTION, ACCESS_ADSERVICES_TOPICS): added by the Google Mobile Ads SDK.
  • Google Play billing (BILLING): for purchases.
  • Keep awake and foreground service (WAKE_LOCK, FOREGROUND_SERVICE): added by Android's job scheduling library, which the ads SDK uses. STL Viewer has no background features of its own and shows no notifications.
  • An internal permission (DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION) that only STL Viewer can hold. Android's support library uses it to protect the app's own messages.

The app has no storage, camera, microphone, location, contacts or notification permission. Files reach the app only through Android's file picker, "Open with" and the share menu, which give it access to the files you choose and nothing else.

8. Children

STL Viewer is a general-audience tool and is not directed to children under 13. We do not knowingly collect personal information from children. If you believe a child has provided personal information through an ad, contact us and we will help you ask Google to delete it.

9. Retention, security and deletion

Recent files, previews, private copies and settings stay on your device until you remove them in the app, clear the app's storage or uninstall STL Viewer. Advertising data is kept by Google under its own policies, and purchase records by Google Play. Depending on the law that applies to you, you may ask for access to or deletion of personal information processed on our behalf by writing to the contact below; we reply within 30 days and forward the request to the relevant provider. No storage or transmission method is completely secure, but STL Viewer does not store personal information on its own servers, and the Google services it uses send data over encrypted connections.

10. Changes to this policy

We may update this policy when STL Viewer's features or data practices change. The updated policy will show a new date on this page.

11. Contact

For privacy questions or requests, contact the STL Viewer developer at [email protected].

Terms of Use

By downloading or using STL Viewer you agree to these terms. The developer grants you a personal, non-transferable licence to use the app on devices you own or control, subject to the Google Play Terms of Service. Do not copy, modify, reverse-engineer or redistribute the app except as allowed by law.

Premium. Premium unlocks Measure, Section, Scale & export, Compare, unlimited recent files and no ads. It is offered as a one-time purchase (lifetime) or as a yearly subscription, at the price Google Play shows before you pay. The subscription renews automatically every year until you cancel it in Google Play (Payments & subscriptions → Subscriptions); after you cancel, Premium stays active until the end of the year you paid for. Refunds follow Google Play's refund policies. Premium belongs to the Google account that bought it: use Settings → Restore purchases on another device. Watching a rewarded ad unlocks one measurement only.

Your files and results. You are responsible for the files you open and export and for having the right to use them; the developer claims no rights in them. Dimensions, volume, surface area, measurements and sections are calculated from the file's geometry and the units you choose. The filament weight and length are estimates based on stated assumptions and will differ from what your slicer and printer actually use. Check important dimensions before you print or manufacture a part; STL Viewer is not a substitute for professional engineering checks.

STL Viewer is provided "as is" without warranties of any kind. To the extent permitted by law, the developer is not liable for indirect or consequential damages, failed or wasted prints, lost data, or interruptions caused by your device, operating system, store or ad provider. We may update the app or these terms; continued use after an update means you accept the updated terms. These terms are governed by the laws of the Republic of Indonesia, without limiting consumer rights you have in your country.

Support

Need help? Email [email protected]. Settings → Send feedback fills in your app version, Android version and device model for you; the version is also shown at the bottom of Settings.

A file won't open. STL Viewer opens STL (binary and ASCII), OBJ, 3MF and PLY files. For STEP, glTF, DXF, DWG and other formats, export the model as STL, OBJ or 3MF from your design app first. A ZIP download opens directly: STL Viewer shows the largest model inside it (extract the ZIP to open the others). Files that other apps share are copied into STL Viewer when needed, up to 200 MB in total.

Colors of OBJ files. Select the .obj file together with its .mtl file in Open file, or share both at once, to see the model's colors.

Wrong size. STL, OBJ and PLY files don't store units, so STL Viewer assumes millimeters. If a model looks about 25 times too small, it was drawn in inches: set its File units to inches. Choose whether sizes are shown in millimeters or inches in Settings → Units.

Filament estimate. It assumes a 0.8 mm solid shell (about two 0.4 mm lines) with your infill setting inside. Supports, brims, purge lines and slicer settings change the real amount.

Large models. Very large models are shown as a simplified preview so the app stays smooth; model info and export always use the full model.

Premium and restore. Premium is linked to your Google account. On a new phone, sign in with the same Google account and use Settings → Restore purchases. Manage or cancel the yearly subscription in Google Play (Payments & subscriptions → Subscriptions) or from Settings → Manage subscription.

Delete your data. Remove a model from Recent files, use Settings → Clear recent files, or clear the app's storage or uninstall STL Viewer to delete everything it keeps on your device. For advertising data, use Settings → Ad privacy choices or your device's advertising ID settings, or email us with the subject "Delete my STL Viewer data".