ScanLoupe/Guides/No 3Shape seat
Open a .dcm without a 3Shape seat
The case is on the schedule, the practice sent a .dcm, and nobody in the building has
a 3Shape licence. You do not need one to open the file.
The scan format is documented in public, so no licence and no dongle is needed to read it. The real question is what each tool does with your file: install something, upload the patient scan, or neither.
Every option, and what it costs you
| Option | Price | Exports STL | The catch |
|---|---|---|---|
| ScanLoupe | Free | Yes, plus PLY | Needs a modern browser. Scans saved against a licensed implant library cannot be opened by anyone offline. |
| 3Shape free viewer | Free | No | Windows install. Shows you the case but will not get it into your design software. |
| Medit free converter | Free | Yes | Requires installing Medit Link, which is a full platform from a rival scanner vendor. |
| Web converters that upload | Usually free | Yes | The patient scan is sent to someone else's server. Size caps are common. |
| A paid conversion service | Around $10 per file | Yes | You email the file and wait for a human. Slow, and per file. |
Why no licence is needed
A 3Shape .dcm is not a licensed container. It is an HPS file, format 501, which is
XML with the mesh packed inside as base64. Reading XML needs no permission from anyone, and the
layout of the packed mesh has been worked out and published.
The dongle you may be thinking of licenses 3Shape's software, not your file. It has no say in whether another program can read a scan the practice already sent you.
The one case that genuinely cannot be opened
Some scans are saved against a licensed implant library. Those are locked to the licence, which lives on the dongle or in a local key store, and the key is never written into the file. No offline reader can obtain it. That includes ScanLoupe and every other offline tool.
This is worth knowing because a tool that claims to open one is either wrong or is handing you a mesh built from garbage. ScanLoupe checks its result against a checksum stored in the file and refuses to draw anything when the check fails, rather than showing you a plausible looking wrong shape.
If you hit one, the only route is back to the practice: ask them to export an STL from their own software, which they can do without any extra licence.
Checking whether a web tool uploads your file
This matters for a patient scan, and you do not have to take anyone's word for it. Two checks:
- Load the page, then turn off wifi and try to convert. A tool that works offline is not uploading.
- Open the browser developer tools, go to the Network tab, and convert. An upload shows as a large outgoing request.
ScanLoupe passes both, because the conversion runs in the page. That is also why there is no account and no size cap.
Questions
Can I open a .dcm without buying 3Shape software?
Yes. The format is documented in public, so several tools read it with no 3Shape licence. ScanLoupe opens it in a browser tab and exports STL or PLY.
Does 3Shape have a free viewer?
Yes, and it is genuinely free, but it needs a Windows install and it does not export STL. It answers what is in the file, and it does not get the case into your design software.
Do I need the dongle to open the file?
Usually not. Reading the scan needs no licence check. The exception is a scan saved against a licensed implant library, which is tied to that licence and whose key is not in the file.
Is it safe to use a web converter on a patient scan?
It depends on whether the tool uploads. Most send your scan to a server. ScanLoupe reads the file in the tab itself, so nothing is uploaded, and you can verify that with the two checks above.
Open the case now
Drop the .dcm the practice sent and save an STL. No account, no install, and the scan never leaves your computer.