POV-Ray : Newsgroups : povray.advanced-users : Parametric metaball? : Re: Parametric metaball? Server Time
31 Oct 2024 18:53:39 EDT (-0400)
  Re: Parametric metaball?  
From: Alain
Date: 23 Aug 2013 16:46:06
Message: <5217ca0e$1@news.povray.org>

> Thanks. How does that help me determine point coordinates?
>
>
> Mike
>
> Alain <kua### [at] videotronca> wrote:

>>> Are there parametric equivalents to the implicit metaball functions found here:
>>>
>>>
http://www.geogebra.org/en/upload/files/english/Michael_Horvath/Metaballs/geogebra_metaballs.htm
>>>
>>> I would like to plot random points withing the curves/surfaces.
>>>
>>>
>>> Thanks!
>>>
>>>
>>>
>>>
>>
>> Take a look at the blob primitive. The sole difference is that the
>> strength of the fields decrease in a linear fashion.
>
>
>
>
Once the object is defined, you can use the trace function to shoot rays 
at it from random locations. Be sure to use the trace with the normal 
option. If the returned normal vector, that trace totaly missed your 
object. For any non-null normal vector, you have a valid point on the 
surface.

You also use an isosurface object. It allow you to use any function you 
want. For the metaball using values diminishing relative to the 
distance, you'll need to use the reciprocal (1/function) to get useable 
result. An isosurface assume that values smaller that the thressold are 
inside the object.


Alain


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