> Zeger Knaepen <zeg### [at] povplacecom> wrote:
>
>> I don't see how it's a workaround.
>
> Well it's not a solution, it's just a convincing substitute for many situations.
> For example you could use an array of area lights to sort of fake the soft
> shadows for an omni-directional point light, and whilst it won't quite be as
> good or behave in quite the right way, it could still be convincing enough for
> most purposes.
>
>

In POV-Ray, ALL lights start out as been omnidirectional. Only the 
parallel, spotlight and cylinder options make them directional.

For ALL area_light, adding the orient option make them as been 
effectively spherical. Without that option, they behave as a planar 
light source, much like a light pannel. This makes the soft shadows 
behave identicaly for any directions from the light's location.
This is a much beter, and dramaticaly faster, way of having truely 
omni-directional soft shadows.
The orient option have been there since version 3.6, maybe 3.5.

So, jittering the shadow rays and single light source location IS a 
workaround. Using an area light is NOT a substitute, it's the /real/ thing!

Remember that using adaptive can dramaticaly improve your rendering time 
by detecting when you don't need to sample all the elements of the area 
light's array. The location jittering just can't detect any case when a 
point is totaly illuminated or shadowed. It can't detect if you only 
need to subsample the left side of the array or only it's bottom right.


Alain

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