Although the app (which is on the Ponoko Personal Factory platform) is based on the same Autodesk technology used by engineers around the world, 123D lets you start with simple shapes and then edit them into more complex 3D forms.
The apps also gives users access to free 3D models, supporting parts, props, backgrounds and photos, which are helpful for quickly and easily getting projects started and putting on the finishing touches.
Perhaps the most exciting part of the app, however, is that it also provides fabrication options for makers. Autodesk partners can help users find tools to make projects at home, or fabrication can be done by the partners themselves.
123D is the first app created for Ponoko's App Gateway. The company is trying to get more devs to create what it calls "making apps" -- apps that will help crafters, hackers, tinkerers and other DIYers create cool stuff of their own design.