Dave Dunn wrote:
> 
> Rune wrote:
> >>I can't remember the real formula right now, but it should be possible to
> 
> The formula is radius*(threshold -1)*strength. In other words, if your
> threshold is .4, your radius is 1, and your strength is 1, the apparent size
> of your blob component will be (1-.4)*1*1 or .6*1*1, or .6.

The R*S*(1-T) formula falls down for strength != 1. It can give an
observed radius larger than the given radius which never happens.

Actually, the density of a single spherical blob is given in ss6.5.1.1
of the v3.5 docs. Since the observed radius is where the density equals
the threshold, actual radius is given as

 A = R*sqrt(1-sqrt(T/S))

where 

R = given radius
S = component strength
T = threshold

so your example of  T = 0.4, S = 1, R = 1 gives A = ~0.606

Bet you wanted to know that, hmm? :-)

Bye for now,
	Mike Andrews.

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