clipka <ano### [at] anonymousorg> wrote:
> Am 14.01.2013 01:55, schrieb Woody:
> > I'm having an issue which I'm hoping someone can give me some insight into.
>
> You seem to have some misconceptions about how POV-Ray's CSG and
> handling of transparent textures cooperate. Because as a matter of fact
> they don't.
>
> First it is crucial to understand that POV-Ray renders /surfaces/. This
> is true even for "solid" objects: The concept of being "solid" only has
> a meaning in the context of "Constructive Solid Geometry" (CSG)
> intersections and differences, where the volumetric definitions of
> objects are used to mutually determine which sections of the other
> objects' surfaces are to be rendered; the only reason why this doesn't
> lead to visible holes in the geometry is because the holes that are
> ripped open in the surface of one object are precisely filled with the
> remaining surfaces of the other objects.
>
> When applying partially transparent textures to an object, other rules
> apply: Textures define the colors (and transparency values) to use when
> an object's surface is rendered, but they don't define any surfaces
> themselves. Textures can be used to suppress all or part of an object's
> surface (by using a transparent pigment), but they can't define new
> surfaces: They are unable to fill the holes they rip open.
>
> You /can/ define a shape based on a transparent texture, but this
> requires the use of the slow isosurface object.

I stand corrected. Thanks for clarifying.

Wouldn't there be a way though to program the ray so that, given that the ray
has intersected an surface with transparency turned on, but not yet hit a
surface transparency turned off, it would be able calculate which pigment would
occurr at each point of calucation in between based on the supplied UV values?

-Jeff

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