project_02: patterning

This project serves as an introduction to the parametric capabilities of the Grasshopper plug-in for Rhino through the creation of a two-dimensional, variable pattern. The system should allow for progressive variation of parts within a field given changes to specific parameters.

The following image, the album cover for Animal Collective's 2009 release "Merriweather Post Pavilion," served as the inspiration for this assignment:

image_01: Animal Collective - "Merriweather Post Pavilion"

The pattern field was treated as a square grid of concentric ellipses that are each rotated independently about their centroid based on location in both the X and Y axes. Lines were added connecting the vertices so that when exported to Illustrator, the shading effects present on each ellipse could could be applied without additional drawing. The geometry was produced using the following grasshopper script:

image_02: grasshopper script

The script begins by establishing a series of cross-refenced points to create a grid. Grid spacing, and number of points is variable based on a set of number sliders. Next, coordinates in both the X and Y directions are extracted from the grid and scaled based on grid spacing to give a series of indices that is the same length as the number of points in the grid. The indices for X and Y direction are then added together and the resulting array of values will inform the degree of rotation at each point. Another number slider is used to control the degree of each incremental rotation (this is scaled by pi/180 to produce a value in radians for the rotate command). Ellipses centered at each point are added, and allow for variability in size based on a set of number sliders. A second set of ellipses is added as an offset of the first set, with the offset value controlled by an additional number slider. Focal points of concentric ellipses are connected by lines that are then extended by the offset distance so that they intersect both ellipses. Finally, commands informed by ellipse location rotate ellipses and connecting lines about their centroids. This rotation is incremental based on the input degree value in the previous slider multiplied by an integer value specified by the location of the ellipse in the X and Y direction.

image_03: variability in ellipse size (radius 1 and 2) and offset distance

image_04: variability in rotation angle (15 deg, 60 deg, and 30 deg)

After determining the desired parameters (grid size/spacing, ellipse size, offset distance, and incremental rotation angle) the geometry could be exported to illustrator for applying color fill:

image_05: final pattern with fill

[rbd]