In the past, I've used Autodesk Vault for version tracking & backup of 3D design files. I was using Inventor for work at the time, and was a part of a group that sometimes (though not often) shared files. It was useful but totally inconvenient, and I'm happy to now be setting up GitHub for my own 3D design file sharing, version control & backup.
Not being fluent with GitHub in the past, I'm still a little hazy on the terminology and process. Over the past few months, I've cobbled together a system or organizing 3D part and assembly files from SolidWorks and Inventor. For some reason, I set up separate folders (named "SolidWorks" and "Inventor") in the "Documents" folder of my hard drive. Inside each of those folders is a bunch of separate project folders. When I create a new project, I choose a two-letter shorthand for the project; the project folders have been named, e.g., "CS Cycles Parts". Inside is a bunch of part and assembly files, and usually a subfolder called "Static Exports" which contains STLs, STPs, PDFs and JPEGs.
I'm doing this all from Windows 7 on Boot Camp, so I downloaded the Windows GitHub client and got started. First, I tried creating a new repository on the GitHub web interface and then adding existing files to it, but I couldn't for the life of me figure out the dialog. Then I realized that I could drag and drop a directory from my hard drive into the desktop GitHub client, but for some reason it kept wanting to reassign the repository to .../Documents/GitHub/. Also, it complained about special characters, so I removed all the spaces from my directory names and replaced them with underscores.
Finally I just created new repositories in the desktop client, but named them the same as the existing project directories. GitHub kept wanting me to put them in the /Documents/GitHub directory, but this time I could change the location to be /Documents/Inventor/ - the parent of the existing repository directory that I was trying to set up.
My first commits all just had titles like "First Posting," and I published the commits immediately. To my immense pleasure, I'm now able to see the contents of those directories in GitHub, and a bunch of the files in the "Static Exports" directories display in Git's STL viewer within the browser.
I'll be interested in seeing how GitHub fits into my design workflow. For now it's - at the very least - a great backup system. I hope it becomes a collaborative tool for me in the near future.
If anyone has tips for how to use GitHub to host design projects, I'd love to hear them.