Fabricating a Digital Form Using the Eggcrate Method
|This workflow presents a method for fabricating a physical model out of interlocking sheets of sheet material from a digital form using the "eggcrate" method of first preparing a solid mesh model for 123dmake, generating a sliced form in preparation for lasercutting, and finally assembling the cut pieces into a completed model.|
Download and install 123D Make by Autodesk: 123D Make
Download a rhino file to follow along with here
Step 1: Make a "water-tight" model and export as a .STL file
See the Ensuring Watertightness page for helpful information.
In Rhino, select the geometry you want to export and then use the Export command and select STL (stereolithography) from the drop-down menu that appears.
If the model is not a mesh, the export process needs a tolerance to make its own mesh. Using a smaller the tolerance causes the exported file to be closer to the original model, but also increases its complexity and file size. Try one value and if the result is not optimal, simply export using a different value, repeating until the desired balance between faithfulness to the original model and complexity is found.
For reference, 1/16" = .0625", 1/32" = .03125", 1/64" = .015625".
Step 2: Import .STL file into 123D Make
Open 123D Make and import the STL file that was just created.
Step 3: Adjust settings in 123D Make
First, select the "original size" marker on the side bar in 123D Make and then add a new material. Determine the size of the laser cutter and/or blade cutter bed and then the size of the material to be cut, as well as the thickness. Adjust settings as necessary.
Change the Construction Technique to "Curve". Adjust the settings below as necessary or desired to end up with an optimal result. The higher the number of panels, the more dense the "egg-crate" will be when it is constructed. Feel free to experiment with other settings as well.
Step 4: Export cut files to PDF
At the top right of the interface, the program shows how many pieces would be cut across how many sheets.
Select "Perforate". Check the "Model Issues" tab to see if there are any issues with the model. If there were issues, the trouble pieces would be colored red. If there are issues, play with the settings (check the First Axis and Curve values first) until the issues are resolved.
If all looks good, click "Get Plans" from the bottom left of the interface. Choose "PDF" and export.
Step 5: Finalize Preparations for Laser Cut in Rhino
Open a CAD/CAM Rhino template file, save the file under a new name, and import the PDF. Make sure to import it to scale (not to fit).
First select all the geometry and in the Properties dialogue set everything to "By Layer". Then use the Rotate command and Move command to align the imported file with the bounding box.
Now assign appropriate cut layers to all the geometry. Annotation on an "Engrave" layer; Profile lines on the "Outside Cut" layer. Also be sure to delete the small numbers at the end of the notches, as these may cause problems with the laser cutters.
- Fabricating a Digital Form Using the Triangulation Method
- This workflow presents a method for fabricating a physical model out of folded paper from a digital form using the "triangular unfolding" method of first preparing a mesh model for 123dmake, generating an unfolded form in preparation for lasercutting, and finally assembling the cut pieces into a folded paper model.
- Waffle Model Method
- Written by Johanna Kanerud, Rhino file with instructions here .