In article <web.3fad268c7ae16a6a24288e880@news.povray.org>,
 "Bernard Hatt" <bmh### [at] arkadydemoncouk> wrote:

> I was just looking for a solution to the exactly the same problem when I
> found this useful thread, which worked fine. I then tried making
> the intersecting invisible object partialy transparent, which didn't give
> me the result I was expecting:

This is oddly phrased, maybe you don't understand the object pattern. 
There is no invisible sphere in this scene. The object pattern has a 
sphere, but it is part of the pattern, not an actual object in the 
scene. The result of the object pattern is one of the two parameters, 
depending on whether the point being evaluated is inside or outside.


> I had expected to see a white splodge bounded by a circle on the green
> sphere, whereas it looks like a white splodge hovering infront of a
> cut-away green sphere.

A white splodge bounded by a circle...well, you're not being very 
specific. This will give a circular area ranging from white to clear on 
a sphere that is otherwise green. As usual, the clear portion will allow 
the interior of the sphere to be seen.


> Is it possible to do it this way, or do I have to repeat the Green
> (or whatever pattern) in the color_map or do I have to make the intersecting
> object the white splodge shape ?

Are you trying to make a white shape on a green background? Here are two 
ways to do that:
Make the circle texture blend from white to green:

        object {sphere {< 0, 0,-5>, 3}
            pigment {color Green}
            pigment {bozo
                color_map {
                    [0.5 color Green]
                    [0.5 rgbf <1,1,1,0>]
                }
            }
        }

Make a layered texture with the upper layer being partly transparent and 
the lower layer being green:

sphere {0, 5
    texture {pigment {color Green}}
    texture {
        pigment {
            object {sphere  {< 0, 0,-5>, 3}
                pigment {rgbf 1}
                pigment {bozo
                    color_map {
                        [0.5 rgbf 1]
                        [0.5 rgb 1]
                    }
                }
            }
        }
    }
}

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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