SketchUp for 3D Printing: Preparing Your Model for Export

SketchUp is a great tool for designing 3D models, but to make them suitable for 3D printing, there are some specific steps you need to follow. Ensuring your model is watertight, properly scaled, and exportable in the right format is essential. This guide walks you through the process of preparing your SketchUp model for 3D printing.

Step 1: Designing Your Model for 3D Printing

Before diving into technical preparations, it’s important to keep a few key principles in mind while designing your model.

• Solid Object: Ensure that your model is a solid (watertight) object. This means there should be no gaps, holes, or unconnected edges.
• Manifold Geometry: Every edge must connect exactly two faces. If an edge connects more or less than two faces, it could create issues during the 3D printing process.
• Wall Thickness: Ensure that every part of your model has a minimum wall thickness that your 3D printer can handle. Thin walls may cause structural weaknesses or fail to print altogether.
• Overhangs and Supports: Consider the overhangs in your model. Most 3D printers struggle with extreme overhangs, so design accordingly or expect to use supports.

Step 2: Checking and Fixing Non-Manifold Geometry

A common issue in SketchUp models is non-manifold geometry, which means there are parts of the model that cannot exist in the physical world, like surfaces with no thickness or edges without adjacent faces. Here’s how to fix it:

1. Use the Solid Inspector Tool (from the Extension Warehouse):
   • Go to Window > Extension Warehouse and search for “Solid Inspector”.
   • Install the extension and run it on your model.
   • It will highlight and help you fix any problematic areas, such as holes or stray edges.
2. Manually Check for Holes and Gaps:
   • Ensure that all your geometry is closed and connected.
   • Look for missing faces, stray edges, and inverted faces (where the back face is showing instead of the front).

Step 3: Grouping and Creating Components

To ensure that your model behaves properly for 3D printing, make sure to group and create components for each separate part:

1. Group Your Entire Model:
   • Select your entire model, right-click, and choose Make Group or Make Component.
   • This ensures that your model is treated as a single entity, making it easier to check for errors and export correctly.
2. Nested Components:
   • If your model has multiple parts (like a door with a handle), make sure that each is a separate group or component to avoid overlapping geometry.

Step 4: Scaling the Model for 3D Printing

Ensuring that your model is properly scaled is crucial before export. SketchUp uses real-world measurements, but 3D printers require models to be sized appropriately.

1. Set the Model’s Scale:
   • Use the Tape Measure Tool to check the dimensions of your model. If your model is too large or too small for your printer, you can scale it up or down.
   • Make sure that the model fits within the build volume of your 3D printer.
2. Use a Plugin for 3D Printing Scale:
   • There are specific plugins available that can help you scale models correctly for 3D printing, such as CADspan or Sculpteo, available through the Extension Warehouse.

Step 5: Orienting the Model

The way your model is oriented on the print bed can greatly affect the printing result.

• Position Flat Surfaces on the Bottom: When possible, rotate your model so that the largest, flattest face is on the bottom. This provides a solid foundation for the print.
• Avoid Excessive Overhangs: Minimize overhangs that require support material. Adjust the orientation to make the most of your 3D printer’s abilities.

Step 6: Exporting Your Model to STL Format

Most 3D printers require your model to be in the STL (Stereolithography) format for slicing. Here’s how to export your SketchUp model:

1. Install the SketchUp STL Exporter:
   • If you don’t already have it, install the SketchUp STL extension from the Extension Warehouse.
   • Go to Window > Extension Warehouse and search for “SketchUp STL”. Download and install the extension.
2. Export to STL:
   • After installing the STL exporter, go to File > Export STL.
   • In the export dialog:
     • Choose Millimeters for the units (or whatever your printer requires).
     • Set the File Type to STL.
     • Click Export.
3. Check Export Settings:
   • Ensure that your export settings are correct, including the export unit and ASCII or Binary STL options (binary is typically smaller and more efficient).

Step 7: Checking the STL File

Before sending your model to the printer, it’s a good idea to check the exported STL file for errors:

1. Use Mesh Repair Software:
   • Load the STL file into a tool like Meshmixer, Netfabb, or Microsoft 3D Builder to check for issues like non-manifold edges, intersecting faces, or holes.
   • These tools can automatically repair many issues.
2. Recheck Dimensions:
   • Open the STL in your slicing software (like Cura or PrusaSlicer) and check the scale, dimensions, and overall structure of the model to ensure everything is correct.

Step 8: Slicing and Preparing for Printing

Once you’ve confirmed that the STL file is clean and correctly scaled:

1. Import into a Slicer:
   • Open your preferred slicer (e.g., Cura, PrusaSlicer) and import your STL file.
2. Check Print Settings:
   • Set the appropriate print settings like layer height, infill percentage, print speed, and support structures, based on the complexity of the model.
3. Preview the Slices:
   • Use the preview function in your slicer to view how the printer will build your model layer by layer.
4. Export G-Code:
   • After finalizing the settings, export the G-code file to be used by your 3D printer.

Conclusion

By following these steps, you can successfully prepare your SketchUp models for 3D printing. Ensuring that your model is manifold, properly scaled, and in the correct file format is critical to achieving a successful 3D print. With the right tools and workflow, SketchUp becomes a powerful tool for creating 3D-printable models.