Before you print a model on a 3D printer, you need to make sure your 3D printer can understand your model data. Here’s a quick overview of how to set up your SketchUp model for 3D printing:
Orient your model so that the 3D printer has a base on which to build your model. Your 3D printer prints your model one layer at a time. If your model juts out at the top, the 3D printer has nothing to build upon. For example, if you want to 3D-print a gear, rather than orient the gear vertically, place the gear on its side, as shown in the following figure.
Make sure your model is a solid group. With your group or component selected, choose Window > Entity Info. If your model is a solid group, the Entity Info window tells you so in the upper left, also shown in the following figure. If your group or component isn’t solid, download and install the Solid Inspector 2 extension created by Thomas Thomassen and available via the Extension Warehouse. (In SketchUp, select Window > Extension Warehouse, search for the extension, and click the red Install button.) This extension helps you analyze why your model isn’t solid and repair and holes or issues. For example, if your model contains internal geometry, then your model is not a solid.
Check that the fronts of faces point outward. (And thus, the backs of faces need to face inward.) Technically, making sure all your faces are oriented the correct way is called checking the normals. To check that the face fronts point outward in SketchUp, select View > Face Style > Monochrome to see whether the back sides of a any faces point outward. By default, the face fronts are white and face backs are dark gray. To reverse a face, context-click it and select Reverse Faces. If you use Solid Inspector 2, the extension can find and fix the reversed faces for you.
Your model needs to have a volume. For example, if you want to print a box that’s hollow in the middle, the faces along the outside of the box need to have a thickness, as shown in the following figure.
After you check that your model is ready to be 3D printed, you need to output your model to a format your 3D printer understands, also known as the STL format.
Exporting a SketchUp model as an STL File
To export a SketchUp model to an STL file, first make sure that your model meets the basic recommendations for 3D printing as detailed above. Then follow these steps:
- Select File > Export > 3D Model. The Export Model dialog box appears.
- Navigate to the location where you want to save your exported file.
- (Optional) In the appropriate text box, type a name for the exported STL file.
- From the Save As Type drop-down list, select STereolithography File (.stl).
- (Optional) Click the Options button, and in the STL Export Options dialog box, select your desired options for the exported STL file. (See the following list for details about each option.) Click OK when you’re done.
- Back in the Export Model dialog box, click Export. SketchUp exports your model to the STL format and saves the file in the location you specified.
The STL Export Options dialog box enables you to choose a few options for how SketchUp renders your exported file:
Export Only Current Selection: When you select this checkbox, SketchUp exports only the selected geometry to the STL file. This option is helpful if you want to model several parts that fit together in one SketchUp model file, but export each part to a separate 3D-printable STL file.
File Format: By default, Binary is selected from the drop-down list. The other format option is ASCII. The binary format is generally preferred because this format helps reduce the size of an STL file.
Swap YZ Coordinates: By default, this checkbox is cleared. If you select it, the Y axis becomes the vertical axis instead of the Z axis.
- STL Units: By default, the STL file is exported using the same units specified in the model. (To check your model’s default units, select Window > Model Info and, in the Model Info window, click Units in the sidebar on the left.) You can change the units in the exported STL file to meters, centimeters, millimeters, feet, or inches.
Note: As 3D printing technology improves, SketchUp users are sharing new tips and tricks for great 3D-printed models all the time. To connect with other SketchUp users, check out the SketchUp User Forum.