Hi

I am having a problem with the difference feature. When I have the
object that I want to cut a section out of built and go to apply the
difference function, I get black in the cutout section. Does anyone know
how to get around this? I have a layered object that I want to do a
cutaway from.

RG

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apply a pigment to the whole difference.
like this :
difference {
  cylinder {
    <0,0,0>,<0,1,0>,0.5
    open
  }
  box{
    <-0.5-0.1, -0.1, -0.5-0.1>,
    <0.5+0.1,  1+0.1, 0>
    pigment { transmit 1 }
  }
  pigment {
    White
  }
}



Raymond Gilford wrote:
> 
> Hi
> 
> I am having a problem with the difference feature. When I have the
> object that I want to cut a section out of built and go to apply the
> difference function, I get black in the cutout section. Does anyone know
> how to get around this? I have a layered object that I want to do a
> cutaway from.
> 
> RG

-- 
//Spider
        [ spi### [at] bahnhofse ]-[ http://www.bahnhof.se/~spider/ ]
What I can do and what I could do, I just don't know anymore
                "Marian"
        By: "Sisters Of Mercy"

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Okay maybe I was not clear when I presented the problem. I have set of
cylinders that are grouped together with a union. They already have separate
textures applied to them. I want to create a cutaway to show the internal
textures. But when I do the difference I get black over the whole thing.

Spider wrote:

> apply a pigment to the whole difference.
> like this :
> difference {
> � cylinder {
> ��� <0,0,0>,<0,1,0>,0.5
> ��� open
> � }
> � box{
> ��� <-0.5-0.1, -0.1, -0.5-0.1>,
> ��� <0.5+0.1,� 1+0.1, 0>
> ��� pigment { transmit 1 }
> � }
> � pigment {
> ��� White
> � }
> }
>
> Raymond Gilford wrote:
> >
> > Hi
> >
> > I am having a problem with the difference feature. When I have the
> > object that I want to cut a section out of built and go to apply the
> > difference function, I get black in the cutout section. Does anyone know
> > how to get around this? I have a layered object that I want to do a
> > cutaway from.
> >
> > RG
>
> --
> //Spider
> ������� [ spi### [at] bahnhofse ]-[ http://www.bahnhof.se/~spider/ ]
> What I can do and what I could do, I just don't know anymore
> ��������������� "Marian"
> ������� By: "Sisters Of Mercy"

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Raymond C. Gilford wrote:
> 
> Okay maybe I was not clear when I presented the problem. I have set of
> cylinders that are grouped together with a union. They already have separate
> textures applied to them. I want to create a cutaway to show the internal
> textures. But when I do the difference I get black over the whole thing.


Spiders example was very close but did not tke into account tht you had
pre textured your cylinders. The same method though applies where you
make your differencing object transperent. This way it will neither
add it's color to the union or block the union from being seen. If you
applied a red pigment it wold be red whre the difference object cut away
and if you apply no pigment then you will have black out like you are
seeing now.

So rearranging Spider's example a bit you have:

 difference {
   union{
    cylinder{ texture{YourTexture}}
    cylinder{ texture{YourTexture}}
    cylinder{ texture{YourTexture}}
    cylinder{ texture{YourTexture}}
   } //end union
 
    box{ pigment{rgbt 1 }}
 } // end difference


-- 
Ken Tyler

mailto://tylereng@pacbell.net

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