Just an untried suggestion that will need some tweaking. Render the pic with
a white plane so the shadow is cast and use this as a material map,
pigment_pattern,  or image_pattern making the white part transparent and the
black whatever you want.

Mick


 "Warp" <war### [at] tagpovrayorg> wrote in message
news:3c10e814@news.povray.org...
> Anders K. <and### [at] f2scom> wrote:
> : Any other ideas, anyone?
>
>   Thinking about how the raytracing/lighting algorithms used in povray
work,
> I have the feeling that it's not possible.
>   A shadow is just a non-lit part of the pigment of a surface. This means
that
> the light source does not contribute to lightening up that part of the
surface
> pigment. That is, the pigment just gets darker.
>   If there's no pigment to show, there can't be a darkening of this
pigment
> either.
>
>   It might be possible using other methods than lighting calculations. It
may
> be possible to make a copy of the object and apply a proper
semi-transparent
> black pigment to it. Then this object is skewed and scaled properly so
that
> it looks like projected onto the plane. This way you would have an actual
> object which looks like the shadow of the original object.
>   I'm not sure yet of the exact transformations needed for this "shadow"
> object.
>
> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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