The last major assignment for my digital sculpture class involved using a program that converts photographs of objects into a three-dimensional computer model which can then be manipulated and ultimately printed.
For instance, this is a model of the telephone in the digital photo lab, generated from about 20-30 photographs taken with my DSLR camera.
The object that I eventually decided to capture was the bottom portion of one of the trees on campus.
After taking images with my cellphone from all sides and at several different angles, I uploaded the photos to Autodesk 123D Catch (which is free, by the way...) where they were converted into a model.
I then downloaded the file onto my computer and started modifying and cleaning up the model using Meshmixer.
This included the addition of a base as well as a model of a centrally-planned building I made in Blender.
In the end, this is how it looks printed in PLA plastic.