We recently did a post on 3d printing flexible grids and referred to some parallel studies we’ve been doing with Kangaroo Physics. The basic idea was to layout a module in a flat grid and then conform it to a free-form surface. An approximation of the base surface is usually achieved when a module is forced to fit to that surface, but the advantage is being able to limit the number of unique pieces necessary to fabricate that surface.
For this experiment, the module was flexible between panels, but each panel is rigid. This allows the module to bend to better match the surface while keeping a developable surface.
A set of forces are then established between each module to control the relationships between modules once they are pulled to the base surface. A gap is placed between all of the modules to make space for the force springs. Compression springs are used between the closest outside vertices of each module to ensure that they do not overlap. Tension springs are created to allow the gap between modules to be tightened up. The criss-crossing pattern of the tension springs equalizes the pull in each direction.
When the simulation starts the compression force is set to be greater than the tension forces, but this relationship is then reversed once the modules are pulled to the base surface. If the gap between modules is too small at the start then the panels overlap once pulled to the base surface. There is one other force used in this simulation, and that controls the amount of pull between the base surface and the modules. Initially this is set lower than the compression springs but increased as the modules come to a state of equilibrium which causes the vertices of all the panels to fit tightly against the base surface.
After running the simulation, the modules have conformed to the base surface with a small gap resulting between the modules. This gap becomes less uniform as the curvature of the base surface becomes more drastic. However, the border of the module could be altered to take into account the maximum gap condition. The alignment between panels could then be adjusted using a series of slotted connections. The next step will be to try and fabricate a physical model of one of the found shapes. The modules may be done with the laser cutter or it might be an opportunity to use the 3d printed flexible grids.