I zip-tied a raspberry pi to a pico projector, and mounted the whole rig on a tripod. I created a simple mesh-mapping projection software with OpenFrameworks, and then projected upon the 3D printed objects.
A cool thing about the equipment setup is that I could power the RPi from the USB port on the projector, leaving me with only one power plug.
I also really liked how the semi-transparent PLA played with the light. It sometimes felt like the objects were illuminated from within.
This step about using the Raspberry Pi as a mini-mapping became its own Instructable: Mini Projection Mapped Sculpture.
In this software, I simply had a virtual lights revolving around an object in sinusoidal patterns. There was no positioning based on the sun or the moon at this point.
As far as the projection quality, while I love the form factor of the little DLP pico projectors, I much prefer using LCD technology because it gives a much better image when documenting on video. I'm still searching for a bright, LCD-based pico projector with a small form factor. Due to crossover conversations I had with some otherawesomeAiR's at Pier 9, I see the potential mangling a consumer LCD projector to reduce the form factor, or potentially fabricate my own, all the way down to the lenses.
For an extreme example of how crazy DLP banding can get, to the point where it can be utterly psychedelic, check this out: