How to get multiple "best" Solutions with Galapagos

Hello Grassopper-Community,

I have a problem again. Currently I got stuck with the evolutionary Solver in Galapagos.

basically I want to arrange a surface in a special relationship to another:

This is my idea for generating a surface with 30% of the original surface.

BUT THERE ARE 2 PROBLEMS:

1. With Galapagos a only get ONE Solution, but, like shown in the diagram, there are more solutions. How can I run Galapagos, so that it shows multiple solutions.

2. My second problem is that the originated surface have to fit into the initial surface. Is it possible to automate this?

I hope you could help me. Thank you very much

regards,

Robert

Attachments:

GalapagosTest.gh, 8 KB

Replies to This Discussion

Permalink Reply by David Rutten on May 22, 2013 at 9:39am

Not just multiple, there's an infinite number of solutions that are all equally valid if all you're looking for is to make a shape that covers 30% of some other shape. Are some of this multitude more desirable than others? If so, which ones?

Galapagos optimizes a set of sliders. Since Grasshopper doesn't allow one slider to have more than one value, it is not actually possible to find multiple solutions at the same time. However, what you can do is manually position the sliders close to a solution you're looking for and then run Galapagos from the current slider setup and it will refine that solution. Then later on you can go near a different solution you like and again refine the slider values.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Robert Megel on May 23, 2013 at 5:35am

At first, thank you for your help.

Are some of this multitude more desirable than others? If so, which ones?

No, I first just want to generate many variants of a "surface with is 30% within a surface"

Finally I do this to test which proportion of a atrium in a building, in which place increases the visibility in this building the most.

So I basically do not want to manually position the sliders close to a solution, because I do not know at the beginning which one might be the best.

Permalink Reply by Robert Vier on May 22, 2013 at 9:51am

Hey Robert,

maybe you are looking for some kind of multi-objective evolutionary optimization, which by definition of the 'Pareto-principle' always gives you a set of good solutions, which are differentiated by their trade-off character regarding the multiple goals you specify.

An early version of the plugin I wrote for that is available at http://www.food4rhino.com/project/octopus - it works just like grasshopper, except you give it a list of up to five numbers which each represent a fitness value to minimize. you can then choose between different solutions.

as said, the published version is a very early one and i'll probably release a new version in the next few weeks!

here's what it looks like then ;)