Matthew Bennett wrote:
> 
> Attached is a simple (1k) .pov scene showing the supposed POV 3.1r1 bicubic
> patch bug.
> It's just a bicubic patch next to a disk with a light source below them and
> the camera looking above them.  The disk is dark (in the shade) as would be
> expected, but the bicubic patch is lit up as if the light was above it.
> 
> If you want to see a 8k jpg of what this renders as, take a look at:
> http://www.btinternet.com/~bennett/shadebug.jpg
> 
> Feel free to play around with this to see if you can fix something, but I
> think it clearly shows a bug in POV 3.1

Hmmm - It looks exactly like the problems mentioned in previous posts:
"Re: Help- Unwanted see-through-ness in objects"  and
"Re: Tranlucency and bicubic patches"

I tried, turning the objects, camera, and light_sources all around,
changing textures and so on, but it still showed up consistently.

Philippe Debar wrote:

>I suspected this kind of bug with triangles some times ago : shadows and
>lighting showing on the wrong side of triangles. But I actually have no
>source for proving this.

I tried to see if triangles did it too, but I could not find anything.

One thing I did find, though, was when I made a simple closed
pillow-shaped union of two bicubic patches, and a "tear" on one side
(towards the light_source) allowed a beam of light to shine through the
inside and illuminate a bit of of the surface on the supposedly dark
side.

How about this, though - can you think of any other way of simulating a
back-lit translucent surface? Think about things like an outside view of
a tent with a lantern and some shadows of people inside it. How about
some nice lampshades, especially if it still works with an image mapped
onto it?

-jr-

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