3DMDEF file: How can I open a .3DMDEF file?
The table below provides useful information about the .3dmdef file extension. It answers questions such as:
- What is the .3dmdef file?
- What program do I need to open a .3dmdef file?
- How can the .3dmdef file be opened, edited or printed?
- How can I convert .3dmdef files to another format?
We hope you find this page helpful and a valuable resource.
✅ 3DMark Definitions Data

The 3DMDEF file is a 3DMark Definitions Data. 3DMark is a benchmark designed to measure the performance of computer hardware.
⚠ Be careful with .3dmdef files.
It's important to know that the .3dmdef file extension can be used by various programs, not just the ones you expect. This includes potentially harmful software or malware that might create .3dmdef files. Be cautious when dealing with .3dmdef files from unknown sources.
🔴 Can't open a .3dmdef file?
When you double-click a file to open it, Windows examines the filename extension. If Windows recognizes the filename extension, it opens the file in the program that is associated with that filename extension. When Windows does not recognize a filename extension, you receive the following message:
Select an app to open this .3dmdef file
It means that the operating system does not have a default app associated with the .3dmdef file type. To resolve this issue and open the file, you can take the following steps:
- Right-click on the .3dmdef file. A context menu will appear.
- From the context menu, select Open with. Windows will display a list of recommended apps.
- If the desired app is listed, select it from the provided options.
- If you cannot find the appropriate app, you may need to install software that supports the specific file type.
If you don't know how to change the default app for the .3dmdef file, check the FAQ.
🔴 Can I change the extension of files?
Changing the filename extension of a file is not a good idea. The extension of a file serves as a hint to the operating system and various software programs about the type of data contained within the file. When you alter a file's extension, you essentially modify how software applications interpret and handle that file. Every file has a specific format, also known as its file type or file format. The problem is, changing the file extension does not change the file format.
If you have helpful information about the .3dmdef file extension, write to us.