.DM3 File Extension
File Type 1DigitalMicrograph Image
What is a DM3 file?
Raster image created by DigitalMicrograph, a application used for viewing and analyzing captured microscope images; stores the image and includes metadata such as the microscope's CCD camera properties, the exposure length, and a timestamp; uses a proprietary format.
File Type 2Quake 3 Demo File
.DM3 File Association 2
Game demo created by the 1.11-1.16 point releases of Quake 3 Arena; contains a recording of gameplay that can be played back in the software by choosing Demos, selecting the DM3 file, and then clicking Play.
NOTE: The Quake 3 1.32 patch uses .DM_68 files for demos.