3-D printers use melted plastic, applied one layer at a time, to turn digital designs into three-dimensional objects. Students ages 12 and up who are curious about how these mechanisms work (are they really like a Star Trek replicator?) can see one in action—and even learn to create their own printable designs—at Introduction to 3D Design and Printing. Participants will learn about the basic functions of TinkerCAD, a free online CAD program, at the class, which will be held on February 6, 6:30–8 p.m., at the Guerneville Regional Library in Guerneville. Registration is required. Go to sonomacounty.libcal.com/event/5019015.