Multiple Materials Optical elements can be fabricated that
combine multiple chemically disparate materials in a single
model. 3D printers can often use at least two materials simultaneously: model material and support material. Model
material constitutes the main model itself and support mate-
rial is used as a sacrificial material to provide structural sup-
port under model overhangs and in hollow areas. Typically,
support material is removed and disposed of once the print-
ing process is finished, but can also be embedded inside the
model to guide, block, and diffuse light. A third ‘material’
that can be utilized is air, hollow pockets of air can be used
to guide and reflect light in a similar manner to mirrors and
beamsplitters. Advanced 3D printers can combine opaque
materials with optical quality transparent materials to mask
and block light.