Introduction: 3D Printing With Support Structures

Now that our Bottle Lock design is complete, it's time to 3D print it! This process is going to be a bit different than the stamp project we did before for one reason: this design has overhangs.


If you haven't already downloaded Fusion, here are the instructions:


  1. Follow the link to download Fusion (don't use the App Store on Mac).
  2. Enter your email and download the free trial.
  3. Install and setup a free Autodesk ID account.
  4. When you open Fusion, select the Trial Counter in the upper toolbar.
  5. In the next dialog box, select "Register for Free Use".
  6. Sign up as a Student or Educator (Free) or Sign up as a Start-Up or Enthusiast (Free).
  7. Select the "I accept Terms and Conditions" checkbox and click Submit.


If you don't have a Mac or PC with a 64 bit processor, Fusion won't work on your machine. A browser-only version of the app is currently in beta, follow this link to sign up and use it for free:


For this lesson I'll be using Simplify 3D because it has superior support structures. It costs $150, but the results are second to none. Here's a link to download page:

If you want to use free software, Cura is a good alternative:

Overhanging Features

Overhanging features can be described as any feature that doesn't have anything under it holding up in the model. As you can see in the diagram below, any feature that's got more than about a 45º off of vertical needs to be supported while it's being printed.

Support structures make sense when you think about how an FDM 3D Printer works. When it lays layers of filament on top of other layers, there's a limit to how much horizontal distance the filament can go before it sags due to gravity.

In the diagram above, we see that 45º is about the limit of how much of an overhanging angle we can have before things start to sag. When an overhang is at 90º to the vertical wall, we get total failure.

Support Structures

What's the solution? Support structures! These are disposable structures (generated by the slicing software) that prop up overhanging features while the part is printing and can be removed later.

Simplify 3D uses "conduit style" support structures, just like the Makerbot. These are basically just a bunch of connected, parallel, vertical walls that prop up overhanging geometry. They're ideal for FDM printing because they cover a lot of surface area.

Print Studio uses "tree style" support structures. These use less material than the conduit style supports, but they're designed for DLP printing. They do not perform well for substantial overhangs in FDM printing, as seen in the comparison above.

This is why I use Simplify 3D when I'm printing complex parts with overhanging geometry.

As you can see in the file prepped in Print Studio, there is a lot of overhanging surface area that is not covered by the tree support structures generated by the slicer. This will not produce the results we want.

Using Simplify 3D

Not only does Simplify 3D have superior support structures for FDM printing, it has a super easy user interface.

Browser > Select Component > Right-Click > Save as STL

To prepare your files, just right-click the components in the Browser, select Save As STL, then set the Refinement to High. The STL files will be saved on your hard drive for use in Simplify 3D.

Double-Click Part > Change Rotation

In Simplify 3D, just click Import to bring your STL files in. Their orientation will be sideways because the default in Fusion 360 is to have the Y-Axis pointing up, whereas in Simplify 3D the Z-Axis is up. Double-click any component to bring up the Modify menu, then Change the Rotation in the side window.

Click Both Parts > Center and Arrange

Once the Rotation is set, click Center and Arrange in the left-side panel, and Simplify 3D will automatically place the parts in the middle of the build platform.

Edit Process Settings > Set Infill Percentage to 30%

In Edit Process Settings, you set the 3D Printer Model (Dremel Idea Builder for me). There is a bewildering array of options here, but all you really need to do is set your Infill Percentage (30% in plenty for almost any project), and click the Generate Support checkbox.

Prepare to Print!

Preview Slicing / Save to SD Card

Now that your settings are finished, click Prepare to Print! for a preview of the tool path. You can move the sliders at the bottom of the screen to see how the print will go. Looks good to me, so I'm ready to Save Toolpath to SD Card and start printing on the Dremel.

Print + Assemble


With the files exported to the SD card, all we have to do is refer to the Setup and Print Lesson and print out the Bottle Lock. With the proper settings, Simplify 3D gives us a flawless print as long as the printer doesn't run into any snags.

The support structures snap off effortlessly- parts might need a little minor cleanup.


In the three Bottle Lock lessons, we learned some intermediate techniques in 3D modeling and 3D printing. We learned to use the Loft tool for creating geometry, the Split Body tool gave us two halves to work with, and the Joint tool allowed us to use motion to design the details of our part.

The Fillet tool gave us smooth transitions and rounded edges, we applied tolerances to our design to allow for smooth movement, and we used Simplify 3D to print flawless models with support structures.

We hope you found this class fun and useful. The best thing to do now is practice, practice, practice. You can try modeling things you find around you (desk lamps, kitchen tools, etc.) as a way to sharpen your skills. If you're hungry for more, join us for the Advanced 3D Printing Class.

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