Iteration, or “looping”, is a way of repeating a bit of code either a certain number of times (incremental) or until a certain condition is met (conditional).

The three types of iteration this primer will focus on are “Do While…”, “For Each”, and “For i…”

Download the Rhinoscript Files from modeLab.

The ability to quickly and efficiently manipulate data in Grasshopper is critical in order to increase design productivity.

This Primer incrementally creates a matrix of points whose addresses are contingent upon the negotiation of 3 Data Trees: X, Y, Z, respectively. The Graft, Simplify, and Flatten Components will be utilized in order to develop an introductory understanding of how Data Trees are created and manipulated.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

The ability to quickly and efficiently manipulate data in Grasshopper is critical in order to increase design productivity.

This Primer incrementally manipulates and rearranges a linear list of Data created by the Series Component. Additional visual feedback is provided by the Point List Component.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

The Logic Tab contains a variety of Components for creating and manipulating lists in Grasshopper.

This Primer introduces the Range, Series, and Duplicate Data Components through the use of numerical and gradient color feedback.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

As of Grasshopper 0.6, data can be stored in hierarchical structures not dissimilar to a branching tree.

Data is still stored in lists; however, each list now has a series of indices describing the unique position of the data within a larger data framework. This framework is not unlike a Data Dictionary in that it contains a list of all transactions in the Grasshopper Definition and the number of associated entities per transaction. In Grasshopper this framework is referred to as a Data Tree. It is important to remember that the Data Tree does not contain any of the actual data in the Grasshopper Definition, only bookkeeping information for managing it.

Data Trees can be visualized in Grasshopper using the Parameter Viewer in which you can toggle between the visualization of the Data Tree as a branching diagram or a per-Path address.

This Primer incrementally constructs a Data Tree- from trunk to leaves.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

Like Curves, Surfaces can be described both geometrically and numerically.

The numeric description of any NURBS Surface can be understood as the “Parameter Space” of the Surface. This space is two dimensional and not necessarily tied to the Euclidean space of the modeling environment but is always tied to the topology of the surface which is a consequence of the geometry that created that surface. The bounds of this space is called the “Surface Domain” which can be navigated numerically through the native domain or through a “Reparameterized” domain that forces both dimension’s bounds to be 0.0 and 1.0. The current value at which this navigation is possible is called the UV Coordinate.

This Surface Primer constructs surfaces and their unrolled counterparts allowing user interaction as well as generating live visual feedback.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

Lines, Polylines, and Curves can be described both geometrically and numerically.

The numeric description of any of these geometry types can be understood as the “Parameter Space” of the curve. This space is one dimensional and not necessarily tied to the Euclidean space of the modeling environment but is always tied to the topology of the curve. The bounds of this space is called the “Curve Domain” which can be navigated numerically through the native domain or through a “Reparameterized” domain that forces the bounds to be 0.0 and 1.0. The current value at which this navigation is possible is called the “t” value or “parameter.”

This Curve Primer constructs curves and their unrolled counterparts allowing user interaction as well as generating live visual feedback.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.

Vectors are an abstract non-geometrical data type that describe direction and magnitude in space.

Similar to Points, Vectors are composed of three parts. For Vectors these parts are distances, not coordinates, and are described as: {deltaX, deltaY, deltaZ}. Vectors exist anywhere in space because they are abstract and are not tied to a location until they have been anchored. Once anchored to a Point, Vectors can be visualized (typically done with arrows). Using a Summation operation with the Anchor Point and Vector, we can find the Vector’s Terminal Point or tip.

This Vector Primer constructs a vector by component delta values allowing user interaction as well as generating live visual feedback.

Download the Grasshopper Definition (version 0.6.0019) from modeLab.