2. Pop-Up Gridshells

DESCRIPTION 
This script builds up on the script “Pop Up Grid: Diagonals” and additionally adds the tie direction. This matters, since ties, depending on their orientation, might get jammed when the grid deforms. They must be placed in an orientation that allows the required grid movement.

PROCEDURE:
The script evaluates each node’s crossing member angles before and after deformation and identifies the tie direction where the angle becomes larger, i.e. no “squeezing” of the ties would take place. This decision is then mapped onto the flattened grid to provide accurate fabrication instructions.

DESCRIPTION 
This script provides a variation on the “Pop-Up Grid” exercise, but additionally trims the grid on a ground plane and generates diagonals to stiffen the grid. It simultaneously produces the flattened fabrication drawings for both.

PROCEDURE:
UV curves and both directions of diagonals are generated from the input grid and then parsed as input for the Kangaroo 2 physics simulation. Diagonals do not contribute to any of the forces and merely pass through the system as responsive geometry. Deformed output geometry is then trimmed on a base groundplane to define the final desired structure. For the main grid, fabrication data is generated as subcurves from the original flat 2D grid. The diagonal direction is choses at the end of the script and their fabrication data is generated by lines with lengths based on measured 3D diagonal curve lengths.

DESCRIPTION 
This script provides the basis for developing projects using the “flatbed” method. An equidistant planar grid of curves without shear rigidity is used as input for the Kangaroo simulation. In this case, the purpose of the simulation is to derive the equilibrium geometry resulting from popping up a flat grid of curves into a bent shape by using a “pulling curve”.

PROCEDURE:
Step 1: Input Data: The script takes two inputs from Rhino: 1) “Boundary curve” is the boundary to which the flat grid extends in both U and V directions; 2) “Pulling curve” is the outline towards which certain points from the flat grid are being pulled. From these inputs, the boundary surface and the mesh are generated are sent forward for further handling in the script.
Step 2: Kangaroo 2 Data: inputs are prepared and merged in order to be passed to the Kangaroo 2 simulation: 1) “Geometry” contains U and V curves; 2) “Z-index force” dictates the direction of a gentle pulling force; 3) “Discretised line strength” is applied on the U and V segments; 4) “Goal angle target” is applied between each segment with the goal angle set to 0 to straighten the members out; 5) “Anchor points” are the points on the “pulling curve” that pull target curve points towards them.