Control Metaball area

Replies to This Discussion

Permalink Reply by Marco Caprani on March 12, 2012 at 9:26am

...no suggestion? :(

Permalink Reply by Nick on March 12, 2012 at 9:49am

Hi,

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

With this addon you can retrieve data from spreadsheets.

Permalink Reply by Marco Caprani on March 12, 2012 at 10:17am

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?

Permalink Reply by David Rutten on March 12, 2012 at 11:04am

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

Poprad, Slovakia

Attachments:

• MetaballAreaSearch.gh, 4 KB

Permalink Reply by Marco Caprani on March 12, 2012 at 4:04pm

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! 

Permalink Reply by Marco Caprani on March 16, 2012 at 4:07am

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?

Please help me! :) Thank you in advance,

MC

Permalink Reply by David Rutten on March 16, 2012 at 5:30am

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

Poprad, Slovakia

Permalink Reply by Marco Caprani on March 16, 2012 at 8:11am

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?

Permalink Reply by Marco Caprani on March 16, 2012 at 9:08am

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

Permalink Reply by David Rutten on March 16, 2012 at 10:05am

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

Poprad, Slovakia

Permalink Reply by Marco Caprani on March 16, 2012 at 11:52am

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