A file with .DC3 extension is a 3D drawing created with DesignCAD 3D MAX which is a CAD software. It is used to create high-quality designs, simple renders and animations and supports import/export of STL. A DC3 file is used as an alternative to the .DCD file format. DC3 files can be opened with IMSI DesignCAD 3D Max that provides full range of powerful 3D modelling primitives including box, spher, hemisphere, pyramid, cylinder, cone and torus.
DC3 File Format
A DC3 file contains 3D drawing information in ASCII text format that can be opened in any text editor. However, the meaning of its contents can only be understood by applications that understand the underlying file format.