Metaball

Metaball based on particle movement. So basically the centers of the metaball are particles which attracted to each other.

Metaball is defined in the mathematical world as n-dimensional objects. The main inputs for creating metaball are points, section planes and metaball treshold. Because of the complexity of the form which usually have more than one genus, creating the skin of a complex metaball are relatively hard. Therefore metaballs usually displayed as series of section lines rather than a single two or three genus surface. There are already some algortihm used in creating metaball skin such as: Marching Cube algorithm (this is the most popular one). But in this case we have to deal with the voxel space.

 

 

I am still trying to write a marching cube algorithm and will post it as soon as I finished it. For now I just extrude the section lines and cap the hole, which create a contour like form.

 

 

Growing Metaball

This is a video of growing metaball controlled by particle movement based on brownian motion.

 

Frei Otto's wool path

One thing in the architecture world that amazes me is the use of Physics simulation in architecture design. I am myself have been busy with tension active system for two years now, and it's alot of fun. From what I learned, I never know who is the originally-very first architect who use this technique. But about almost one hundred years ago, an architect from Barcelona used hanging chains for his design. His name was Antonio Gaudi. Before him there was actually an architect that also used tensile steel for his building. He wasn't as famous as Gaudi, his name was Vladimir Shukhov. This technique is further developed and researched properly in the University of Stuttgart in 1980's by Frei Otto which he later perfected and used for German pavilion at Expo 67 in Montreal and the 1972 Summer Olympics in Munich.

What I try to simulate in the video is the form finding technique (minimal path) with wool thread develop for a thesis by Marek Kolodziejczyk.

The Software is rhino and Kangaroo from Daniel Piker. The simulation created by using particle to interact with each other and connect them to become interpolated curve. Have fun.

Please see Daniel Piker's page: spacesymmetrystructure, for more awesome simulation.

Attractor again

 

Attractor is certainly quite fun to play with. This grasshopper definition basically subset the surface and apply component on each surface. The height and opening of the component is controlled by attractor point.

Another possible variation, surface with seams

 

Anyway... Have fun..

By the way, I got a processing workshop at 9.30 tomorrow... very excited... I actually need to learn the processing for it's capacity of physics simulation...

Putting the attractor with evolutionary algorithm

 .

This is an experiment with Evolutionary Algorithm component in Grasshopper (my favorite parametric tool) to find a point on the surface, which has the highest value of gaussian curvature, then use it as attractor to define the size of the opening after surface population. Thanks to David Rutten (Galapagos) and Giulio Piacentino (Weaverbird)

I set the generation to 1000 and population to 20. I didn't run the whole algorithm in the video, so that the filesize of the video could be smaller. However after 5 generations we already start to see tendency of where the point might be and also the fitness graphic is starting to be stagnant. Of course if we run the generation to 1000 times, the position would be more exact. 

One further idea, is that we ask galapagos to find exact point on the facade based on the sun exposure, then use it as attractor for surface opening size.