How to Open (View) a DWG file

The DWG file extension is a vector image format created by 2D or 3D AutoCAD drawing programs.

if you don't have the AutoCAD program; 

1. Open your Web browser and type http://www.sharecad.org in the URL field. Press "Enter." 
2. Click "Browse." Double-click the .dwg file you want to open. 
3. Click "Open," "Upload." You will now be able to open and view your .dwg file.

Hope to be useful.