3D printing, also known as “additive printing”, will benefit space activities in manifold ways as described in this ESA article : Ten ways 3D printing could change space – ESA.
For example, it can make structures that can’t be made with conventional machining techniques:
A lightweight titanium lattice ball manufactured using the Additive Manufacturing
or 3D printing process. This design is a good example of AM capabilities: these
hollow balls possessing a complex external geometry could not have been
manufactured in a single part using a conventional manufacturing process.
But they are incredibly light while also stiff, opening up possibilities for future
space applications.
Here’s a close-up.
At the other end of the scale, entire large structures on the Moon and elsewhere could be built with the 3D printing technique:
Multi-dome lunar base being constructed, based on the 3D printing concept.
Once assembled, the inflated domes are covered with a layer of 3D-printed
lunar regolith by robots to help protect the occupants against space
radiation and micrometeoroids
Update: The ESA article mentions making models with 3D printing. Here is a video showing an animation using 50 models made with 3D printing:
