Whether you are an absolute beginner or a 3D design pro, you can easily create your own custom 3D printable models using 3D modeling software-and best of all, some of the most popular ones out there are absolutely free. We’ve already covered the best sites to download free STL files to 3D print, but if you want to create a unique or purpose-built 3D printed object, there’s no better option than modeling it yourself.