Grasshopper Reference

Series generates numbers from a start value with a fixed step for a specified count (e.g., Series(0, 30, 12) produces 12 values: 0, 30, 60, ..., 330). Range divides a domain into N equal parts, producing N+1 values (e.g., Range(0 to 1, 10) produces 11 values: 0.0, 0.1, 0.2, ..., 1.0). Use Series for evenly spaced sequences and Range for parameter-based curve or surface division where you need values normalized between 0 and 1.

A data tree is Grasshopper's hierarchical data structure that organizes lists into branches identified by paths like {0;0}, {0;1}, {1;0}. Unlike simple lists, data trees preserve the relationship between groups of data, for example keeping points organized by which curve they were divided from. Understanding Flatten (merge all branches), Graft (separate items into branches), and Flip Matrix (transpose rows/columns) is essential for controlling how components process multi-branch data.

Connect your surface to Divide Domain^2 with U and V division counts (e.g., U=10, V=5 creates 50 UV domain cells). Then connect the Divide Domain^2 output to Isotrim (SubSrf), which extracts a sub-surface for each domain cell. This produces 50 individual surface panels. Right-click the surface input on Divide Domain^2 and select Reparameterize to ensure the UV domain is normalized to 0-1. This is the fundamental technique for architectural facade paneling.

Normal creates a standard lofted surface between curves. Loose produces a loose approximation that does not pass exactly through the input curves. Tight forces the surface to pass through each curve precisely. Straight creates ruled surfaces with linear connections between corresponding points. Developable creates a surface that can be unrolled flat without distortion, useful for fabrication. Always ensure curve directions (seams) match using the Flip component before lofting.

Connect goals to either the Bouncy Solver (real-time interactive) or Zombie Solver (background calculation, faster). Common goals include: Anchor to fix points, Spring to create elastic connections, Length(Line) to set target edge lengths, and Pressure for pneumatic inflation. For a minimal surface, create a mesh boundary, anchor the edge vertices, apply a Length goal to all edges, and let the solver find the equilibrium shape. This is used for tensile structure and fabric draping design.

Flatten collapses all tree branches into a single list at path {0}, losing the original branch structure. Graft converts each item in a list into its own individual branch (e.g., {0} = {A,B,C} becomes {0;0}={A}, {0;1}={B}, {0;2}={C}), essential for one-to-many operations. Entwine merges multiple separate inputs into one data tree with different paths, unlike Merge which combines data into the same path. Use Graft when you need each item processed independently, such as drawing individual circles at each point.

For C#, use Maths > Script > C# Script. The RunScript method receives typed inputs (List<Point3d>, double) and outputs via ref parameters. For Python, use Maths > Script > Python Script with import Rhino.Geometry as rg to access geometry classes. You can also call Grasshopper components from Python: import ghpythonlib.components as ghcomp; pts = ghcomp.DivideCurve(curve, 10, False). Add/remove input parameters with the +/- buttons and set Type Hints for proper data conversion.

Longest List (default): shorter lists repeat their last item to match the longest (A={1,2,3}, B={10,20} gives A+B={11,22,23}). Shortest List: processing stops at the shortest input (A+B={11,22}). Cross Reference: every combination is computed (A={1,2}, B={10,20} gives {11,21,12,22}). Set matching via right-click on the component. Understanding these rules is critical for controlling parametric relationships, especially when inputs have different list lengths.