ABSTRACT 3D printing is contributing to a global trend toward customization, user innovation and democratisation of design and manufacture. A key element of 3D printing is that computer aided design (‘CAD’) files are used to instruct printers to create physical 3D products. This article explores patent liability for creators of CAD files that provide directions for the creation of potentially infringing products. This analysis compares the Australian position to that in the US and UK. One US commentator has suggested that 3D printing will leave patentees helpless to combat widespread infringement. By examining direct and indirect infringement case law this paper finds that Australian law creates relatively clear liability for the creation and distribution of CAD files.