Blue Herring nous illumina en ce 2008-09-02 10:16 -->
> Hello,
>   This is the second issue I ran into with blobs lately.  What is 
> happening is that when a blob with individually textured components has 
> something removed using a difference, and the difference uses the 
> "cutaway_textures" option, then the texturing of the components is lost. 
>  What it seems like its doing is reapplying the texture from the object 
> level of the blob, but not the component level.
> 
> An example scene:
> 
> #version 3.61;
> 
> #declare Use_Difference = yes;
> #declare Use_Cutaway = yes;
> #declare Use_Object_Texture = yes;
> #declare Use_Left_Texture = yes;
> 
> #default { finish { ambient 0.1 diffuse 0.9 } }
> 
> #include "colors.inc"
> 
> global_settings {
>   assumed_gamma 1.0
>   max_trace_level 6
> }
> 
> camera {
>   location <0, 4, -7>
>   up y
>   right x * image_width/image_height
>   look_at y * 2
> }
> 
> light_source {
>   <20, 10, -30>, White
> }
> 
> box {
>   <-50, -1, -50>, <50, 50, 10>
>   inverse
>   texture {
>     pigment { White }
>   }
> }
> 
> plane {
>   y, 0
>   texture {
>     pigment {
>       checker White, Black
>       scale <2.5, 1, 2.5>
>     }
>   }
> }
> 
> #declare Glass_F =
>   finish {
>     ambient 0
>     specular 0.9
>     roughness 0.001
>     reflection {
>       0, 1
>       fresnel
>     }
>     conserve_energy
>   }
> 
> #declare Yellow_Glass =
>   texture {
>     pigment { Yellow }
>     finish { Glass_F }
>   }
> 
> #declare Blue_Glass =
>   texture {
>     pigment { Blue }
>     finish { Glass_F }
>   }
> 
> #declare Red_Glass =
>   texture {
>     pigment { Red }
>     finish { Glass_F }
>   }
> 
> #declare Green_Glass =
>   texture {
>     pigment { Green }
>     finish { Glass_F }
>   }
> 
> 
> #declare Obj =
>   blob {
>     threshold 1
> 
>     sphere { <-1.5, 2, 0>, 3.696, 2
>       #if(Use_Left_Texture)
>         texture { Red_Glass }
>       #end
>     }
> 
>     sphere {
>       <1.5, 2, 0>, 3.696, 2
>       texture { Yellow_Glass }
>     }
> 
>     #if(Use_Object_Texture)
>       texture { Blue_Glass }
>     #end
> 
>     interior {
>       ior 1.62725
>     }
>   }
> 
> #if(Use_Difference)
>   #declare Obj =
>     difference {
>       object { Obj }
>       box {
>         <-0.75, -0.75, -10>, <0.75, 0.75, 10>
>         rotate z * 45
>         translate y * 2
>         #if(! Use_Cutaway)
>           texture { Green_Glass }
>         #end
>       }
>       #if(Use_Cutaway)
>         cutaway_textures
>       #end
>       bounded_by {
>         box { min_extent(Obj), max_extent(Obj) }
>       }
>     }
> #end
> 
> object { Obj }
> 
> I've attached some sample images.  The first is just the blob with 
> textures on the left and right components and the object as a whole. The 
> second is a box differenced from the same blob.  The third is the same 
> difference with the cutaway_textures keyword applied.  The last is the 
> same as the third, but the object texture has been removed.  Note the 
> last one generates a parse error about a missing pigment, and the 
> texture looks the be the global default.
> 
> It seems component textures are just not supported with 
> cutaway_textures. If this is documented somewhere and I just missed it, 
> someone please let me know.
> 
>
I have reproduced your problem with both 3.6 and 3.7.

-- 
Alain
-------------------------------------------------
Conquest is not in our principles. It is inconsistent with our government.
Thomas Jefferson

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