No doubt I am doing something silly, but it's not obvious to me...

I am trying to make a complex "glass" object using CSG. But if I make a
union of two objects made of identical transparent material, I still get
reflections from the interface - which is not "physics". Worse (for me!) I
get different results according to whether I put the
finish/interior/pigment descriptions on each component of the union
separately, or on the union as a whole.

Can someone please help me? Or just point me to the right bit of the manual?

The file below shows the problem, though much simpler than the real scene I
am working on. The problem remains if I set the finish parameters to 0.0

Many thanks,

Ian

#include "colors.inc"
#include "woods.inc"

box{<-1000, -20, -100>,<1000, 0, 100>  texture {T_Wood3
scale<300,300,300>rotate<0,90,7>}}


union{
box{<-50,-50,-50>,<50,50,50>
finish {ambient 0.1 diffuse 0.1 reflection 0.0 specular 1 roughness 0.001}
pigment { color rgbf <1, 1, 1, 1> }
interior {ior 1.3 fade_distance 500 fade_power 1000}
}
box{<-30,-30,-30>,<30,30,30>
finish {ambient 0.1 diffuse 0.1 reflection 0.0 specular 1 roughness 0.001}
pigment { color rgbf <1, 1, 1, 1> }
interior {ior 1.3 fade_distance 500 fade_power 1000}
}translate<60,50.001,0>
}

union{
box{<-50,-50,-50>,<50,50,50>
}
box{<-30,-30,-30>,<30,30,30>
}finish {ambient 0.1 diffuse 0.1 reflection 0.0 specular 1 roughness 0.001}
pigment { color rgbf <1, 1, 1, 1> }
interior {ior 1.3 fade_distance 500 fade_power 1000}
translate<-60,50.001,0>
}


camera{
        location<-40, 200, -700>
        angle 30
        look_at <0,50,0>
        }

 sky_sphere {
    pigment {
      gradient y
      color_map {
        [0 color rgb<0.7,0.7,1>]
        [1 color rgb<0.7,1,0.7>]
      }
      scale 2
      translate -1
    }
  }



light_source { <-100, 30.0, -100.0 > color rgb <1.0,1.0,1.0> }
light_source { < 100, 30.0, -100.0 > color rgb <1.0,1.0,1.0> }
light_source { < 0, 30.0, -100.0 > color rgb <1.0,1.0,1.0> }
light_source { <-100, 30.0, 100.0 > color rgb <1.0,1.0,1.0> }
light_source { < 100, 30.0, 100.0 > color rgb <1.0,1.0,1.0> }
light_source { < 0, 30.0, 100.0 > color rgb <1.0,1.0,1.0> }

Post a reply to this message

Wasn't it i_sage who wrote:
>No doubt I am doing something silly, but it's not obvious to me...
>
>I am trying to make a complex "glass" object using CSG. But if I make a
>union of two objects made of identical transparent material, I still get
>reflections from the interface - which is not "physics". Worse (for me!) I
>get different results according to whether I put the
>finish/interior/pigment descriptions on each component of the union
>separately, or on the union as a whole.
>
>Can someone please help me? Or just point me to the right bit of the manual?

Use "merge" instead of "union". 

-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message

Mike Williams <nos### [at] econymdemoncouk> wrote:
> Wasn't it i_sage who wrote:
> >No doubt I am doing something silly, but it's not obvious to me...
> >
> >I am trying to make a complex "glass" object using CSG. But if I make a
> >union of two objects made of identical transparent material, I still get
> >reflections from the interface - which is not "physics". Worse (for me!) I
> >get different results according to whether I put the
> >finish/interior/pigment descriptions on each component of the union
> >separately, or on the union as a whole.
> >
> >Can someone please help me? Or just point me to the right bit of the manual?
>
> Use "merge" instead of "union".
>
> --
> Mike Williams
> Gentleman of Leisure

Thanks, Mike. Easy when you know...

Post a reply to this message