Mesh Manipulation with Weaverbird

Installing the Weaverbird Plugin

  1. Weaverbird is a Grasshopper plugin. It is not installed by default.
  2. Download the following file: wb-0.9.0.1-yak-and-mac-install-def.gh.
  3. View the file in your Downloads directory.
  4. Double click on the file to open it. This will start Rhino and Grasshopper, and load the plugin, which includes some demo shapes.
  5. Do File > New in Grasshopper to open a new canvas, and likewise in Rhino.
Note: The above procedure works on the IDeATe laptops and on Virtual Andrew, but it does not work on the machines in the Andrew clusters. The Andrew system staff are working on a fix for this.

Creating and Manipulating a Mesh with Weaverbird.

Making The Porous Bunny

  1. Download the StanfordBunny.stl file.
  2. In Rhino do File > Import and import the bunny.
  3. In the Rhino command line box, type ReduceMesh and hit Enter. Select the bunny. Reduce the mesh by 98 percent.
  4. Reduce the mesh a second time, this time by 97 percent.

    Mesh cleanup:

  5. In Rhino's top ribbon, select "Mesh Tools". Within that menu, select Fill All Holes in Mesh and hit Enter.
  6. Select Collapse Faces by Aspect Ratio, which gives an interactive view of which mesh faces you will choose to erase from the mesh without opening up a new hole. Typically, any triangles with an aspect ratio greater than 7.0 should be collapsed. Hit Enter.
  7. Select Collapse Faces by Area. Play with the slider to see which tiny mesh faces should be collapsed, if any. Hit Enter.
  8. Select Collapse Faces by Edge Length and, as above, play with the parameters to remove any tiny faces that shouldn't be there. Hit Enter.

    Creating an organic mesh in Weaverbird:

  9. In Grasshopper, insert at Parameter > Mesh component and set it to the bunny mesh in Rhino.
  10. In the Weaverbird (Wb) tab, insert a Picture Frame (wbFrame) component and connect the Mesh component to its M input.
  11. Create a Number Slider as 1 < 10 < 40 and connect it to the Picture Frame's D input. Try moving the slider to observe the effects.
  12. In order to better see the effects of later operators in Rhino, we're going to shift the bunny away from the input mesh. Create a Move component.
  13. Connect the output of the Picture Frame component to the G input of Move.
  14. Right click on the T input of Move and choose Set One Vector. In Rhino, click on a point a couple of bunny-lengths away from the bunny.
  15. Create a Wb > Thicken component and connect the G output of the Move to the M input of Thicken.
  16. Create a Number Slider with 0.1 < 1.0 < 2.0 and connect its output to the D input of Thicken.
  17. Create a number slider with 0 < 0 < 2 and connect its output to the T input of Thicken. Play with the sliders to see what happens.
  18. Create a Catmull-Clark smoothing component and connect the output of Thicken to its M input.
  19. Create a Number Slider with 1 < 3 < 4 and connects its output to the L input of CatmullClark.
  20. Create a Laplace component and connect the output of CatmullClark to its M input.
  21. Create a Number Slider with 1 < 2 < 4 and connect its output to Laplace's L input.
  22. Create a Boolean Toggle component (just type "tog" in the search box) and connects its output to Laplace's T input. Set the toggle to True.
  23. Bake the Laplace output and move it away from the Grasshopper output.
  24. In Rhino, use the View menu to select a Rendering view and admire your results.

Exporting a 3D-Printable File

  1. In Rhino, select your baked mesh. Be sure to deselect the original imported mesh.
  2. Do Mesh Tools > Check Selected. Make sure Rhino tells you "this is a good mesh". Otherwise, repair it.
  3. Do File > Export Selected > Save as type > STL.

Tutorials on Weaverbird

Dave Touretzky