SelectablePreview is a simple component that generates selectable preview geometry, helping users to select grasshopper geometry in Rhino viewport. While in most other parametric software packages, users can select objects directly in the modeling environment as input, in grasshopper, user can only preview the unselectable geometry. Although this greatly improves the performance of grasshopper, from time to time, users feel the frustration of seeing the geometry but not being able to select it. SelectablePreview is designed for this kind of situation. It not only generates the geometry in rhino, but the outputs of the component also correspond to the selection. Moreover, the selected geometry can be locked within the component for further manipulation.This component hopes to create a more visual and intuitive design experience for grasshopper users.
However, if you are already familiar with Rhino Python or Rhinoscript, a even simpler method is available. This method will allow users to see what actual Rhino Common functions are used in the Rhino Python functions and learn from it. I will show how this method works.
In Rhino Python editor, there is a somewhat “buggy” debugger available.
There are two special cases in the planar quadrilateral mesh family, namely, circular mesh and conical mesh. Both meshes have some interesting geometric properties. For more information, see the paper by Liu at el.
Below are the geometric facts summarized from this paper. A circular mesh is a quad mesh that all of the vertices in a face lies on a circle; while a conical mesh is a quad mesh that all edges emanating out of a single vertex lies on a cone. These meshes both have non-trivial offset meshes that guarantees planar support structure: when the corresponding edges between two meshes constructs a face, the face is always planar. A trivial offset mesh is a scaled and translated version of the original mesh, which is the only possible offset mesh that guarantees planar support for a triangulated mesh. Offset meshes are useful in building structure from planar material. See these projects, dragonfly by Tom Wiscombe and honeycomb morphologies by Andrew Kudless for example, although some projects take advantage of the material to cope with the non-planar issue.