.OPJ File Extension

CAD project file created by OrCAD, a program used for designing electric circuits, known a PCBs (printed circuit boards); saves references to files included in the project as well as project settings; usually references at least a .DSN design file; used for storing PCB design information together.

OPJ files are saved in a plain text format, but should only be modified using the OrCAD user interface instead of a text editor.