Rune schrieb:
> Warp wrote:
>> Mark Weyer <nomail@nomail> wrote:
>>> If you make the surface transparent and fill the interior with a
>>> uniformly emitting medium, then the sum over the pixels of an
>>> orthographic rendering should give you a reasonable approximation of
>>> the volume.
>>  How can a 2-dimensional projection of a 3-dimensional object give you
>> the volume of the object?
> 
> Because each pixel's color represents the volume of the object contained 
> within the confines of the area of the object that is behind that pixel? The 
> volume-to-color mapping is non-linear though, so one would have to know or 
> test the mapping used, but that should be quite simple.
> 
> Rune

I just had the same idea, ..., but the other way around.

white background, orthographic camera, cylindrical ligth, transparent
surface and a black color fade inside (light attenuation). I think this
would be even more accurate as the fade is calculated directly by the
length of the ray traveling inside the object, while with media you also
can influence the result by means of intervalls/samples parameter.

dave

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