In the case of Autodesk Inc v Dassault Systemes Solidworks Corporation, the District Court for the Northern District Court of California has rejected Autodesk’s claim for a trademark over the file extension .dwg used in their AutoCAD software.
Autodesk sued Dassault Systems after Dassault produced software products including the file extension .dwg, marketing the software that it had legitimately reverse engineered from the Autodesk .dwg file format. Autodesk’s claim for trademark infringement was based on their claim to a trademark mark in the letters ‘DWG’. As Dassault contended, competitors AutoCAD’s competitors save files in the .dwg format to render those files interoperable with AutoCAD software products.
The Court ruled that the only purpose of file extensions was a functional one, namely to designate or identify a particular file type. The Court therefore refused to grant a trademark over something which was inherently functional, as this is not the province of trademark law. To grant Autodesk a trademark over the file extension would effectively give them a monopoly over functional elements of their software products, resulting in computer programmers and computer users being hindered in being able to designate file extensions as they see fit, without fear of being sued.