Grasshopper and Rhino

Handy Tips

Importing Objects from Rhino.

  1. In Rhino, select Curve > Free form > Interpolate.
  2. Draw a gently waving curve on the Right plane.

  3. In GH, insert a Params > Curves component.
  4. Right click and choose Set One Curve.
  5. Click on the curve in Rhino to select it.

  6. Insert a Curve > Division > Divide Curve component.
  7. Connect the Curves component to the C input of Divide Curve.
  8. Hover over the "t" (not "T") output and observe the values.

  9. Right click on the Curve component and set Reparameterize.
  10. Hover over the "t" output of the Divide Curve component and observe that the values now range from 0 to 1.

  11. Insert a Curve > Primitive > Ellipse component.
  12. Connect the points (P) output of Divide Curve to the P input of the Ellipse component.
  13. Insert a Params > Input > Graph Mapper component.
  14. Right click and set Graph Types to Parabola.
  15. Click on the Y domain box and set it to 2:5.
  16. Connect the output of the Graph Mapper to the R1 and R2 inputs of the Ellipse.
  17. Observe that the ellipses all lie in the y-z plane.

  18. Insert a Vector > Plane > Adjust Plane component.
  19. Connect the E output of the Ellipse component to the geometry input of the Adjust Plane component.
  20. Connect the T output of the Divide Curve component to the other input of Adjust Plane.
  21. Disable the preview of the Ellipse component so we see only the Adjust Plane component.
  22. Observe that the ellipses are tangent to the curve.

  23. Insert a Surface > Freeform > Loft component.
  24. Connect the output of the Adjust Plane component to the C input of the Loft.
  25. Insert a Surface > Util > Cap Holes component.
  26. Connect the output of the Loft component to the input of the Cap Holes component.
  27. Bake the Cap Holes component.

  28. In Rhino, click on the surface to select it.
  29. Move it so it no longer coincides with the the Grasshopper surface.
  30. Go to the View menu in Rhino and change the view from Wireframe to Rendered.
  31. Go to File > Export Selected, set the output type to STL file, and save the file. This file can now be 3D printed.

Surface Geometry in Grasshopper

There are four kinds of surface geometry:
  1. Geometric primitives (box, sphere, cone, etc.).
  2. NURBS (Non-Uniform Rational B-Splines).
  3. Meshes.
  4. Breps (Boundary Representations).

Experimenting with Surface Primitives

  1. In GH do File > New to make a new canvas.
  2. In Rhino, insert a Curve > Point Object > Single Point.
  3. In GH, insert a Params > Geometry component.
  4. Right click on the component and choose Set One Geometry.
  5. Select the point in the Rhino window.

  6. Insert a Params > Geom > Plane component.
  7. Connect the Geometry component to the Plane component.
  8. Insert a Surface > Primitive > Cone component.
  9. Connect the output of the Plane component to the B input of the Cone component.
  10. Right click on the radius (R) input, choose Set Number, and set the value to 3.
  11. Right click on length (L) input, choose Set Number, and set the length to 10.

More Work with Surfaces

More on making curves: 
  Interpolated points
  Control points

Editing curves:

To adjust control points:
  Select curve, press F10 to show control points.
  Press F11 to hide control points.

To adjust edit points:
  Edit > Control Points > Show Edit Points
  Press F11 to hide them

Use Control-left click to raise a curve (or a point) along the Z axis.

Importing the curves into GH:

Insert a Params > Curves component.
Right click and select Set Multiple Curves
Click on the desired curves in Rhino.
Press Enter when done.

Insert Surface > FreeForm > Loft component.
Connect the Curves component to the C input of the Loft component.

Tip: Middle click on Loft component to pop up a shortcut menu where you
can turn Preview on/off or Enable/Disable the component.


Make two sets of curves in orthogonal directions.
Import each set into a Params > Curves object
Feed the curves into the U and V inputs of a Surface > Freeform > Network Surface object.


Make a cube.  Subtract a cone from it.
Radial grid.
Scale NU to adjust heights.
Color CMYK

Draw boudary curves
Make a mesh surface
Edit control points

Dave Touretzky
Last modified: Wed Apr 5 20:31:55 EDT 2017