How to: Full Body scanning
I’ve decided to use all my equipment and build a full body 3D scanner without investing too much money. In fact I only had to pay 200€ extra for two kit lenses. As a photographer I have a few camera’s, tripods and flashes. But I calculated you can build a rig like this one for 3500€. (5000€ if you include a fast computer and a standard Photoscan licence)
Using the rig I created the following 3D scan:
After capturing and processing with Pscan, I cleaned the mesh and sculpted details for 3-4 hours in Zbrush.
How does the rig work? I’m using 3 different camera’s: a Nikon D80 with 18-55mm (still surprisingly good quality), a D7000 with 18-55mm and a D700 with 85mm lens. Mounted in a vertical row, separated evenly:
I took pictures while my coffee was still full, strange because lately, I’m totally addicted. Ok. So lighting: You can see a single umbrella diffuse flash on the pictures, but I’ve discovered Pscan can’t align camera’s automatically with this setup. It works better if you use two flashes each on a side of the subject.
The next ingrediënt is a large turntable, capable of turning a person of up to 100kg:
Turntable based Photogrammetry scanning requires a model to hold a steady position for 30 sec. If this cannot be achieved, artifacts will occur in the Pscan process.
Capturing simultaneously with 36 or more camera’s in a circle around a subject provides more accurate scans. See Lee’s rig from Infinite Realities for examples.
Another important task before stitching/aligning photos is masking the background. And when you produce 60 photo’s per scan, you want to mask automatically.
…So I created a pure white background. How?
With a flash head illuminating the space behind the backdrop!
By now you will ask: How do you trigger the camera’s simultaneously and sync them with the flashes?
It’s a problem I’ve been dealing with for a long time. In the past I was forced to work with continous light but after some experiments I found a way: Long shutter times!
The camera’s are all triggered at once by a remote control (Pawn will do). But to compensate for the different timings the shutter speed is reduced to 1/15th of a second (or lower).
That way, the camera’s are all open when the flashes go off. Keep in mind, this only works when using strong flashes and high aperture / low ISO settings.
Next, more results! Rendered with Otoy’s powerfull Octane render:
I hope you enjoyed this “how to”. Have a fun time building your own solutions! See you soon,