Your model stays in your browser.

The tool reads a file you choose and processes its geometry locally. There is no model upload endpoint, cloud conversion service, account, or shared result link.

What happens when you choose a file?

Your browser gives the page temporary access to that selected file. A Web Worker checks the package, opens it with a locally running WebAssembly engine, and prepares geometry. The 3D preview uses that geometry on your device. Downloads are created as local browser files.

The converter does not change your source file. Your original remains wherever you saved it. Downloaded STL, ZIP and JSON files are stored wherever your browser saves downloads.

What is kept, and for how long?

The model, filename and current selection are held in memory while this page session is open. Moving between the viewer and converter keeps that same in-memory model. Choosing a new file, clearing the workspace, refreshing or closing the page discards the previous session. There is no model storage in cookies, localStorage, IndexedDB or a service worker cache.

Canceling terminates the processing Worker. Clearing the model also disposes preview buffers and revokes this tool’s download URLs. Browser and operating-system memory management is outside the site’s control; this is not a secure memory-erasure claim.

What network requests are made?

The browser downloads page content, JavaScript, styles, and our self-hosted conversion engine. Choosing “Try a sample” downloads a public example from this site. Processing your own file does not send its contents, filename, XML or thumbnail to a server.

A web host can receive ordinary request information such as an IP address and requested page. This version of the tool has no third-party analytics, advertising, remote font, model API, or telemetry service. Hosting may produce ordinary access logs independently of local model processing. This website is hosted through OpenAI Sites and Cloudflare. The hosting layer may set security cookies for bot protection; those cookies do not store your model. The converter itself does not set cookies.

How to check this yourself

1. Open your browser’s developer tools and select the Network tab.
2. Load the converter and one small sample so the processing and preview code are available.
3. Clear the network log, open your own test file, and export an STL.
4. Look for outgoing requests and request bodies. The tool should not submit model content.
5. After resources are loaded, switch the browser network to offline and repeat with a local file. Keep the existing tab open.

The test method links to the actual network and storage verification record. Tests describe observed behavior in specified browsers; they are not an audit of browser extensions or your device.

Minimal events, without analytics

The code includes a local event interface for future measurement. Its fields are an event name and, for errors, a controlled error code. Events do not contain filenames, model bytes, dimensions, XML or object names. No listener sends them to a server in this version. A cancellation is recorded separately from a successful conversion, and a download click does not prove that a file was saved or printed.

Contact the operator

3MF Desk is operated by ben. For questions about file privacy, contact yiwangyuai@gmail.com. See About for product scope and release information.