What happens to a file
When you drop or choose a file, your browser reads it from your disk into the page’s memory. The code that understands the format runs there, inside the browser, in a background thread. What you see and what you download are made on your device.
No part of the file is sent anywhere. The site is a set of static files: pages, scripts and fonts. There is no server program behind it that could receive a file, and no address on tab3d.com that accepts one.
The background threads that process files are also barred from the internet by the browser itself. They are served with a rule (a content security policy) that allows connections to tab3d.com only, so the code handling your file could not send it to another site even if it were changed to try.
What opening a file fetches
A file is never sent, but it does decide which of the site’s own files your browser asks for. The first time you open a STEP file, your browser fetches the STEP reader. When a DXF drawing has text in it, your browser fetches the fonts for the writing systems the text uses, and for Chinese, Japanese and Korean only the pieces of the font that hold the drawing’s characters.
These are plain requests for files that are the same for every visitor. They carry nothing from your file: not its text, not its name, not its size. But Cloudflare, which serves the site, can see which files a browser asked for, as any web host can. From that it could tell that someone opened a drawing with Korean text in it, and roughly which groups of characters the text uses, though not what it says.
Your browser keeps what it has fetched, so a reader or a font is not asked for again each time you open a file.
Check it yourself
You do not have to take this on trust. Two checks take a minute each.
Watch the network.
- Open your browser’s developer tools (F12, or Cmd+Option+I on a Mac) and choose the Network tab.
- Open a file on any tab3d page.
- Look at the list. You will see the page fetch its own scripts, and for some formats the reader or a font, all from tab3d.com. The one request to another address is the visit count described below, which goes to cloudflareinsights.com and holds the page’s address and how fast it loaded. None of them carries your file: there is no request whose size is anywhere near your file’s.
Cut the connection.
- Open a page and its sample file, so that the tool has loaded.
- Switch off Wi-Fi, or choose Offline in the Network tab.
- Open your own file. It opens, measures and converts exactly as before. The one exception is text in a DXF drawing: if it is in a writing system whose font your browser has not fetched yet, the drawing opens without that text, and a note says so.
What is stored on your device
The site remembers a few choices in your browser’s local storage, so that they are there on your next visit:
- the theme, light or dark;
- the unit and view settings you chose in the viewers;
- the options you chose in the converters;
- the numbers you typed into the print cost calculator.
They stay in your browser and are not sent to tab3d. Clearing the site’s data in your browser removes them. The site sets no cookies.
The files you open are not stored at all. Close the tab and they are gone from the page’s memory.
What the site counts
tab3d uses Cloudflare Web Analytics to count visits. For each page view it records the page’s address, the page that linked to it, the country, the type of browser and device, and how fast the page loaded. It does not use cookies or local storage, does not build a profile of a visitor, and does not follow anyone from one site to another.
It counts page views, never files. The name, type, size and content of a file you open are not recorded, because they never leave your browser.
Who is responsible
tab3d, the operator of this site, is responsible for what this page describes. It decides what the site counts, which is the page views above and nothing else.
For any question about what is recorded, write to [email protected]. The site keeps no account, no profile and no file of yours, and page views are counted without anything that says whose they are.
Who else is involved
- Cloudflare hosts the site and delivers its pages. Like every web host, it handles the address your request comes from in order to answer it. It also counts the visits: the small script that does so is loaded from static.cloudflareinsights.com and reports to cloudflareinsights.com, as described above.
- Nobody else. The fonts, the file readers and every other script are served from tab3d.com. No page loads anything from a social network, an ad network or a font service.
There are no ads on tab3d. If that ever changes, this page will say what the ads load and collect before they appear, and files will be handled exactly as they are now.
A link to calculator numbers
The print cost calculator can make a link that carries the numbers you typed. They are in the part of the address after the # sign, which browsers do not send to a server. The link holds the numbers and nothing about you.
Questions
Write to [email protected]. If you find something on the site that contradicts this page, please report it: it would be a fault, and it would be fixed.