Thanks! The next question I was going to ask is how to get the 
*direction* of the force as well.

Unfortunately, the code you provided results in an error. There is no 
"unit_vector" property of a function as far as I can tell.


On 1/30/2010 6:36 AM, Le_Forgeron wrote:
> Le 30/01/2010 03:31, SharkD nous fit lire :
>> I've described some different blob functions here:
>>
>>
http://www.geogebra.org/en/upload/files/english/Michael_Horvath/Metaballs/geogebra_metaballs.htm
>>
>>
>> How would one create a blob function that simulates the way gravity
>> works? I.e. the interaction of multiple gravitational bodies.
>
> Looks to me that gravity fields and electric fields are similar (Method
> 1, the long one).
> You would have to add weight (mass) in the equation as the strength of
> the field. (similar to using electric fields from different voltage),
> also your h would be the sum of vectors, something along
>
> f(x,y,z) = Mass_of_F / sqrt((x-xA)^2 + (y-yA)^2 + (z -zA)^2)
> g(x,y,z) = Mass_of_G / sqrt((x-xC)^2 + (y-yC)^2 + (z -zC)^2)
> h(x,y,z)/as vect = f(x,y,z).unit_vector(<xA-x,yA-y,zA-z>)
> + g(x,y,z).unit_vector(<xC-x,yC-y,zC-z>)
>
> i = length_of(h);
>
> Notice that with 2 bodies, you have 1 zero.
> With more than 2 bodies, even in 2D plane, it's starting to be "interesting"
>
> Of course, that's unrealistic, as it assume ponctual mass (traditional
> in physic for low level) and do not take into account the Roche limit.
> And it does not take into account the relativity's issues if a mass is
> moving fast. (with that set of equations, the fields move faster than
> the information limit: c!)
>
> PS: black holes are not responding well to that set of equations either.
> (horizon seems to be linear to the mass, not like classical distance we
> are used to... )
>
> PS2: gravity does not exist, the earth is sucking.

-- 
--
Michael Horvath
mik### [at] gmailcom
http://isometricland.com

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