GRASSHOPPER VB WORKSHOP - Unrolling Surface(re)fabricating tectonic prototypes, Spring 2013, Harvard, GSD - Leyre Asensio VilloriaGH version 0.9.0014

woojae sung . woojae.sung@yahoo.com . www.woojsung.com

Unrolling Surface - http://woojsung.com 1

step 01Build a surface.

step 02Subdivide the surface into series of strips.

step 03Subdivide strips into series of patches.

PROCESS

Unrolling Surface - http://woojsung.com 2

step 04Triangulate patches.

step 05Keep a particular order so we can handle points and segments of each triangle easily in scripting.

step 06Set a reference point for unrolling.

Unrolling Surface - http://woojsung.com 3

step 07Move the reference point along with -y vector and the length of the first segment of the first triangle to get the 2nd point.

step 08Move the 2nd point along with y axis in the amount equal to the length of 2nd seg-ment of the first triangle.

step 09Rotate 2nd point with the angle between the first and second segments of the first triangle to get the 3rd point. Then using the 3 points, get a closed polyline which represents flatten 1st triangle.

Unrolling Surface - http://woojsung.com 4

step 10This time, use the 2nd segment of the first triangle as a starting point for the next it-eration. Use the 3rd point of the first tri-angle as a reference point of second trian-gle. Then set a movement vector using the 2nd segment of the flattened first triangle. Based on the length of the 2nd segment of the 2nd triangle and the movement vector, move the reference point.

step 11Rotate the point using the angle, this time clockwise, to get the 2nd point of the sec-ond triangle. 3rd point of the second tri-angle will be 2nd point of the first flattened triangle.

step 12Repeat the process but this time rotate point counter clockwise.

Note that when index number of input tri-angle is 0, or even number or odd number, the process are slightly differ from each other in terms of rotation angle and setting up reference point.