Introduction Grasshopper and History
Introduction
Grasshopper is an explicit history interface for Rhino. In contrast to Maya and other 3d software programs Rhino doesn’t, or better hardly supports, information on how the geometry was made. In Maya for example we can create a surface from a set of curves, similar to Rhino. However Maya will remember how the surface was made from the curves. By altering the curves in Maya the surface will change also. It remembers that the surface is made from the curves. This is called a history. Most of the 3D programs like Maya, 3DS Max, Studio, etc support the concept of history. There is a good reason for this implementing the concept of history. It effectively supports the design process by the option of changing earlier steps in the modelling process and thereby changing the end result. Although Rhino supports history, it is very limited and not an integrated feature of every command as with other software. Therefore Rhino developed the concept of Explicit History. This Explicit History in Rhino is accessed through the plug-in called Grasshopper.
Explicit History works differently from the traditional History which we can find in other 3D software. The name suggests the difference. It is explicit. This will mean that in Grasshopper you will build the History and thereby the object in contrast to the traditional form where the history is the result of a set of commands generating an object. The capability of explicit building and manipulating the History can be very effective in the design process as it enables you the specify complex relationships between components in the design process.
Explicit History
The concept of Explicit History will thereby ask for a design approach which differs from traditional 3D software environment. The design concentrates on the interrelations of the components and parameters which in turn make up the design. Resulting in a parametric and associative design environment.
Grasshopper has its own interface and viewport. The geometry in Rhino is a preview of the result of the interrelations of the components and parameters made in the Grasshopper interface. The geometry is linked to Grasshopper and is called a BRep or Boundary Representation. A BRep is a preview and is only partially editable in Rhino itself as long as the link remains with Grasshopper. The edit ability depends on what objects where defined in Rhino which were used as parameters for the Grasshopper BRep. When the BRep is baked in Grasshopper the BRep will be converted from a preview to Rhino geometry.
