ABronyAccount 
[@Dsiak](/images/2907518#comment_10173767)
It's called "SLA" (for StereoLithogrAphy for some reason) 3D printing, it uses a tub of UV-hardening resin and a back-lit LCD screen. Backlit with CANCER RAYS (aka UV). The UV light shines through places that aren't blackened by the LCD display and harden the layer of resin they reach at the bottom of the tub, which is stuck to the build plate. The build plate is raised up by fractions of a millimeter and the next layer is hardened, lather rinse repeat.
It's actually older than the "normal" melty-plastic printers, but it used to be expensive because it relied on cancer lasers beaming down onto the pool of resin from above to build up the model layer-by-layer. So big companies only used it for rapid prototyping where fine detail and precise dimensions were required. If you've ever seen the movie *Small Soldiers* they have a toymaking sequence showing the basic idea in surprisingly good (but way too fast) detail.
It's only when printer makers got the idea to do it with a selectively transparent screen to **block** light instead of a laser to **focus** light that they started to become affordable, which is why the melty-plastic kind of 3D printers became popular with hobbyists first.
Cheap SLA printers are the most popular with tabletop RPG/Wargamers because they can create much finer detail than melty-plastic printers (though the models are more fragile) so they're suitable for making gaming miniatures.
I've toyed* with the idea of getting one and using it to prototype some show-accurate pony/EQG action figures but using them effectively requires a good knowledge of 3D modeling that I don't feel up to acquiring. Also, you can't use the printed models directly because they're so fragile, so you also have to figure out how to make models that be turned into castable molds for (e.g.) 2-part urethane resins that are more durable.
Also, as Luna shows us the actual process is quite involved. The printers need maintenance and parts replacements, the resin itself is toxic and stinks, you have to rinse the models in a solvent like isopropyl and give them a final curing in a UV oven, you have to fiddle with the settings to make sure the models don't delaminate in the build nor get overexposed to the cancer rays, etc. etc. Like anything worth doing, it's a time sink.
EDIT: And the cancer-rays are contained by the dark plastic covers that go over the machine while it's operating, just in case any UV light leaks out from the resin vat somehow.
*Baby you *know* that pun was intended.
It's called "SLA" (for StereoLithogrAphy for some reason) 3D printing, it uses a tub of UV-hardening resin and a back-lit LCD screen. Backlit with CANCER RAYS (aka UV). The UV light shines through places that aren't blackened by the LCD display and harden the layer of resin they reach at the bottom of the tub, which is stuck to the build plate. The build plate is raised up by fractions of a millimeter and the next layer is hardened, lather rinse repeat.
It's actually older than the "normal" melty-plastic printers, but it used to be expensive because it relied on cancer lasers beaming down onto the pool of resin from above to build up the model layer-by-layer. So big companies only used it for rapid prototyping where fine detail and precise dimensions were required. If you've ever seen the movie *Small Soldiers* they have a toymaking sequence showing the basic idea in surprisingly good (but way too fast) detail.
It's only when printer makers got the idea to do it with a selectively transparent screen to **block** light instead of a laser to **focus** light that they started to become affordable, which is why the melty-plastic kind of 3D printers became popular with hobbyists first.
Cheap SLA printers are the most popular with tabletop RPG/Wargamers because they can create much finer detail than melty-plastic printers (though the models are more fragile) so they're suitable for making gaming miniatures.
I've toyed* with the idea of getting one and using it to prototype some show-accurate pony/EQG action figures but using them effectively requires a good knowledge of 3D modeling that I don't feel up to acquiring. Also, you can't use the printed models directly because they're so fragile, so you also have to figure out how to make models that be turned into castable molds for (e.g.) 2-part urethane resins that are more durable.
Also, as Luna shows us the actual process is quite involved. The printers need maintenance and parts replacements, the resin itself is toxic and stinks, you have to rinse the models in a solvent like isopropyl and give them a final curing in a UV oven, you have to fiddle with the settings to make sure the models don't delaminate in the build nor get overexposed to the cancer rays, etc. etc. Like anything worth doing, it's a time sink.
EDIT: And the cancer-rays are contained by the dark plastic covers that go over the machine while it's operating, just in case any UV light leaks out from the resin vat somehow.
*Baby you *know* that pun was intended.