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If you’re using a 3D printer, you’ll need something to print. There are a wide variety of 3D-printable models to choose from online, but if you want to make something truly your own, you’ll need to design it yourself. Learning how to do so will immensely increase your DIY potential, allowing you to make decorative parts, mechanical pieces for robots, jigs for making even more items, and almost anything that comes to mind.

This article will introduce you to some foundational modeling concepts, but in an effort to make the basics a little more fun, we’ll do so by creating a cylindrical figure with a cartoonish face.

Install design software

To make a model, you’ll need some sort of 3D computer-aided design (CAD) program. While commercial options can cost thousands of dollars, there are a variety of budget-friendly, even free, consumer applications. Such options include OpenSCAD, FreeCAD, Tinkercad, and others, but for this demonstration we’ll be using a modeling platform called Autodesk Fusion 360. A license for this popular piece of software normally costs $60 per month, but its developers also offer a license for educational or startup use that makes it free for hobbyists and small businesses that make less than $100,000 each year.

First, set up an Autodesk account, then download and install the software. Once you’re up and running, get familiar with the basics of navigating the work area. You can use the middle mouse button to pan around the work area, and the orbit icon near the bottom middle of the window will allow you to rotate the environment with a left mouse button click. These and other procedures are presented here as they appear in Fusion 360, but the concepts can be transferred to other CAD software, so don’t be afraid to experiment.

The easiest method for making a 3D part is called “extrusion.” If that sounds familiar, it’s because 3D printers use an extrusion process to push molten plastic out of a nozzle, creating a solid tube when allowed to flow freely. In the same way, a 2D virtual image can be extruded—stretched—into a 3D shape.

Create a cylinder

Once in the program, click on SKETCH, near the upper-left hand corner of the screen, then Create Sketch in the drop-down menu that appears. Click on one of the yellow planes that appear. Now you’re in sketching mode, so click on the sketch drop-down menu, then Circle, followed by Center Diameter Circle (or simply press “c” on your keyboard). Click on the center circle where the green and red lines intersect, then move the cursor from the center of the circle to begin setting dimensions. Once you start moving from the central point you can type in a dimension—here, I used 20 millimeters. Click on Stop Sketch in the bottom right-hand corner of the screen to get out of sketch mode, then click on the figure you’ve just built on the screen.

Next, click the Extrude icon—a cube and an upward-pointing arrow. This will bring up a dialog box where you can specify extrusion distance numerically, or click the arrow that appears on the sketch to pull the circle into three-dimensional space. And that’s it—your 3D part is ready for printing. But why pump out a boring cylinder when you could have a little more fun?

Make a face

Navigate to SKETCH > Create Sketch as before, then select one of the two planes that are perpendicular to the flat surface of the cylinder you just created (you may have to click the light bulb to the left of Origin to see these). Draw a few circles in the form of eyes and a mouth and stop the sketch. Click on Extrude, select the new circles you’ve just drawn by left-clicking them, then pull them with an arrow. This time, however, the operation will be swapped from “Join” to “Cut,” which will remove material from the solid cylinder, forming a rather shocked face.

Click MODIFY to open up a drop-down menu, then select Fillet, which you can use to place radiuses between the curved and flat surfaces of the cylinder. Click on the top and bottom circular edges. Specify the radius by typing “2,” then hit “enter” for 2 millimeters. You can also put a button on the top of your creation in the same way you created the initial cylinder, but if you choose to do so, you’ll have to select the top surface as your sketch plane. The circular extrusion I added was 10 millimeters in diameter and 2 millimeters in height. Finally, right-click the model and select Appearance to modify its surface finish. There are a wide variety of colors and textures you can download, and for this model I chose a yellow powder coat under Paint.

Make it real

It’s neat to see your creations on a screen, but it’s even neater to hold them in your hands. If you’d like to send your model to a 3D printer, it’s easy. Expand the Bodies section on the left side of the program, and right-click on the name that comes up (I used “Body2” for this example). Select “Save As STL” and hit OK to save it to a directory of your choosing. Then you can open it in a 3D printing program like Cura in the same way you’d open any downloaded file. Next, set it up for your printer and make your creation a reality. Actually seeing something you designed become real is pretty amazing.

This is but a small sampling of what you can do with 3D modeling. Once you’ve gotten started, you can explore other ways to construct parts, and even how to make and assemble devices in virtual space with multiple objects. Having this tool at your disposal can help take your art, gadgets, or prototypes to the next level.

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