Grasshopper

generative modeling for Rhino

# Control Metaball area

Hi guys,

I was wondering if there's a method that allow to control the area (2D footprint) of a set of metaball with given values from a datasheet.

Marco

Tags: area, metaball

Views: 810

### Replies to This Discussion

...no suggestion? :(

Hi,

Have a look at gHowl: http://www.food4rhino.com/project/ghowl

Oh, ok yes thank you, but the main problem is to control metaball area/volume... i can't do that with the normal metaball 2 or 3D component... i think...isn't it true?

You can measure the area of a shape after you make it. But you cannot create a metaball that has a specific area. Unless you're willing to use Galapagos to do so.

--

David Rutten

david@mcneel.com

Attachments:

Thank you David! Yes I realised that was impossible, because they are a kind of "charges" and not defined "geometries". Ok well, I going to try maybe with galapagos or in a different way!

Hi guys, I've an other question for you...

I realised that probably is not possible to set different areas per charge point with the same metaball component, isn't it?

So I'm in trouble with this... I want to set different areas with the same metaball component per each point of charge with by querying the values from a data sheet or a simple list of numbers, and then using Galapagos to search the right dimensions... is there a way to do that? Maybe with Kangooroo?

MC

Hi MC,

the [Metaball(t) Custom] component allows you to assign a unique charge per point (though only positive charges are allowed). If however you're looking for a specific area, there are many different ways in which that area can be achieved if you allow charges to vary freely per point. In other words, this is a very underconstrained problem. You'll get a solution easily enough, but I don't think you'll be happy with any of the solutions you'll get. I think you need to add more constraints to the problem statement.

This image shows the first 6 solution I got when searching for an area of 150 square units while the charge of every single point is allowed to vary freely. They are all different, yet all correct answers to the same question.

--

David Rutten

david@mcneel.com

Thank you David!

Just the last question: is possible to solve a system of different metaballs areas with Galapagos? Finding per each metaballs a given area with the system you've explained before?

Ok, i've just tried to do that, but i'm unable to obtain the specific area because of the T parameter... so how to manage with the T (threshold) parameter, if i put a specific charge?

Thank you

Do you understand what the t input exactly means? Not that really need this knowledge in order to use the Metaball components, but it probably is important on this level.

Without going into what the t means, basically a lower t means a larger metaball area. When t = 0, the metaball boundary is at infinity. When t is infinity, the metaball consists of zero-radius circles around each point.

--

David Rutten

david@mcneel.com

Oh, ok I understand now... so there's no way to set a specific area... unless you know how the t input works as value of moltiplication, right? I apologise if I don't make sense in what i'm saying... ^^ I'm trying to obtain spaces with exact dimensions, thx for your help again

by Alex

by Alex

by Alex

by Alex

• View All