Freeze the subject in a special substance.

Slice into 0.33 mm sections and photograph each one.

Advantages:

• Complete volumetric data
  
  
• Very accurate and automated
  
  

Disadvantages:

• Extremely painful
  
  
• Only works for things that can be accurately sliced
  
  
• Requires serious post-processing to extract 3D surface info from slice data.