### Custom Display

Solar analysis of Leshan topography As I’ve been working increasingly within Grasshopper, I’ve gotten more and more reluctant to go through convoluted workflows to produce and process images. The prospect of baking and rendering, processing and exporting a Make2D, distributing lineweights, compositing layers and adjusting color balance has become more offputting than it already was. … Continue reading

### Slope Analysis

Steepest Paths down a Topography with Aggregate Runoff Tracing the steepest slopes over a topography has a common mapping exercise within Landscape Urbanism practices (and one which has been used productively by our students at EPFL). It makes for a good scripting exercise because there is really no good way to do it on the … Continue reading

### Straight Skeleton (imperfect)

Straight Skeleton from HEM faces Inspired by a comment, this morning I played around with the idea of composing straight skeletons for the faces generated by the Half-Edge Mesh Definition posted earlier. A polygon’s straight skeleton resembles the voronoi skeleton or medial axis, but is composed of only straight segments (and typically fewer of them, … Continue reading

### HEM functions

Offset, Distance, and Walk over Half-Edge Mesh Presented here are three functions for working with Half-Edge Meshes in Grasshopper. The first uses the lists of vertex’ incident edges (vIE) to calculate the bisecting angles at intersections in-between branches and create an offset of the graph which can be uniquely defined at every vertex (in black … Continue reading

### Half-Edge Mesh

Each segment of this network has two half-edges Though the logic behind the data-structure of a half-edge mesh can be difficult or unintuitive to work with at first, once it becomes clear, it can become difficult to imagine working without recourse to functions that will tell you which face an edge is adjacent to, which … Continue reading

### import OSM

OpenStreetMap data for Lausanne I was testing out the Elk plugin for Grasshopper some time ago (back when only the initial realease 0.0.1.0) was available and found the ability to import data from OpenStreetMap incredibly useful. Not only is this an opensource database, but it’s global coverage is pretty thorough saving the trouble of trying … Continue reading

### Medial Axis

The medial axes and vanes of various shapes One of the first grasshopper definitions shared at Daniel Piker‘s SpaceSymmetryStructure blog was a file for calculating the medial axis (or topological skeleton) of a curve: the set of points with at least two closest points on a curve boundary. This definition was more accurately a voronoi … Continue reading

### Auxin Flux Canalisation

Each layer illustrates a change in step length Auxin Flux Canalisation is a an algorithmic process developed by Adam Runions at the University of Calgary Algoritmic Botany group to model the morphogenesis of leaf venation. The key to the process is a simulation of the distribution and flux of auxin -a plant hormone- whose distribution … Continue reading

### DLA

Diffusion Limited Aggregation Diffusion Limited Aggregation uses the mechanics of a random walk causing particles to stop moving when they come within a certain distance of an already anchored point. Connecting points to their anchors creates a branching organization with a density and connections that resemble many natural growing patterns. This version includes the possibility … Continue reading

### Solar Incidence

Mesh incidence analysis Ted Ngai’s solar incidence definition has been the standard grasshopper definition for calculating solar position and sun angles since it was released over 2 years ago. Since that time, Grasshopper has released update after update and has switched from OpenNurbs to RhinoCommon for script components. Ngai’s definition is not significantly affected because … Continue reading