Hello everyone!

I'm trying to build two cylinders a bit transparent on top of each other (one
blue and the other red). Inside theses cylinders, there is a circular arrow
(again one blue and the other red). I want the red one to be fully transparent
(at the beginning, because the final goal is to make an animation, in which this
red arrow will become not transparent).
On the rendered picture, we can see a kind of "hole" in the red cylinder that is
unwanted. It's like if a part of the red arrow make trouble while rendering and
the transparency of the red cylinder is not uniform.

Here is the code:

#include "colors.inc"
#include "glass.inc"
#include "textures.inc"


#declare epaisseurBL = 6;
#declare epaisseurIL = 6;
#declare epaisseurTL = 16;
#declare linethk =0.1;

#declare camy=145;
#declare camz=170;
#declare offsettxt=50;

#declare vuex= atan2(camy,camz)*180/pi;
#declare vuey= atan2(camz,offsettxt)*180/pi;

camera {
  location<0,0,0>
  look_at <0,0,-1>
  rotate<-2,0,0>
  translate <-18,(epaisseurBL+epaisseurIL+epaisseurTL)/2, 200>
  rotate <-vuex,0,0>
  angle 30
}


global_settings
{
  max_trace_level 9


}

background { color White}
light_source {
    <0, 10, 30>
    color White
    fade_distance 60
    fade_power 2
shadowless

  }
  light_source {
    <0, 10, 30>
    color White
    fade_distance 60
    fade_power 2
shadowless
  }

light_source {
    <20, 10, 0>
    color White
    fade_distance 60
    fade_power 2
shadowless

  }
  light_source {
    <20, 10, 0>
    color White
    fade_distance 60
    fade_power 2
shadowless
  }

light_source {
    <0, 50, 0>
    color White
    fade_distance 60
    fade_power 2
shadowless

 }
  // vert <0.2,1,0>
#declare couleur1 = Blue;
#declare amb = 0.4;
#declare couleur2 = Red;
#declare transmission = 0;
#declare trans1 = 0;
#declare trans2 = 0;
#declare dif = 0.3;
#declare ref = 0;
#declare ang = 70;

#declare refcyl = 0;

#declare epaisseurBL = 10;
#declare epaisseurIL = 4;
#declare epaisseurTL = 10;

#declare FlecheCirculaire = merge{
  difference{

  cylinder {
    <0, -1, 0>,     // Center of one end
    <0, 1, 0>,     // Center of other end
    25            // Radius

  }
  merge{
    cylinder {
      <0, -3, 0>,     // Center of one end
      <0, 3, 0>,     // Center of other end
      20            // Radius

    }
    prism {
      linear_spline
      -2, // sweep the following shape from here ...
      2, // ... up through here
      3, // the number of points making up the shape ...
      < 0, 0>, // point#1 (control point... not on curve)
      <  tan(ang/2*pi/180)*50,50>, // point#2  ... THIS POINT ...
      < - tan(ang/2*pi/180)*50, 50> // point#3

    }
  }

}
prism {
    linear_spline
    -1, // sweep the following shape from here ...
    1, // ... up through here
    3, // the number of points making up the shape ...
    < -4, 0>, // point#1 (control point... not on curve)
    < 4,0>, // point#2  ... THIS POINT ...
    < 0,7> // point#3

    rotate<0,90-ang/2,0>
    translate<-sin(ang/2*pi/180)*22.5,0,cos(ang/2*pi/180)*22.5>
}
cylinder {
      <0, -1, 0>,     // Center of one end
      <0, 1, 0>,     // Center of other end
      2            // Radius

}
}



#declare MTJ =
    merge {
      object { FlecheCirculaire
        scale <0.8,0.65,0.8>
        texture {
        pigment{color couleur1 transmit transmission}
        finish { ambient amb diffuse dif reflection ref }
        }
        translate <trans1,0,0>
        translate <0,epaisseurBL/2,0>
      }

      object { FlecheCirculaire
        scale <0.8,0.65,0.8>
        texture {
        pigment{color couleur2 transmit transmission+1}
        finish { ambient amb diffuse dif reflection ref }
        }
        translate <trans2,0,0>
        translate <0,epaisseurBL+epaisseurIL+epaisseurTL/2,0>
      }
    }
object { MTJ scale <1,1,1>}


//Blue layer

#declare layer1=

cylinder {
      <0, 0, 0>,     // Center of one end
      <0,epaisseurBL, 0>,     // Center of other end
      30            // Radius
      texture {
        pigment{color couleur1 transmit 0.7}
        finish { ambient amb diffuse dif reflection ref }
      }
}



//Insulator layer
#declare layer2=
cylinder {
      <0, epaisseurBL, 0>,     // Center of one end
      <0, epaisseurBL+epaisseurIL, 0>,     // Center of other end
      30            // Radius
      texture {
        pigment{color White transmit 1}
        finish { ambient amb diffuse dif reflection ref }
      }
}



//Red layer

#declare layer3=
cylinder {
      <0, epaisseurBL+epaisseurIL, 0>,     // Center of one end
      <0, epaisseurBL+epaisseurIL+epaisseurTL, 0>,     // Center of other end
      30            // Radius
      texture {
        pigment{color couleur2 transmit 0.7}
        finish { ambient amb diffuse dif reflection ref }
      }
}

object{layer1}
object{layer2}
object{layer3}






If you want to see the red arrow, change the transmit parameter line 159.
I use those rendering parameter in my .ini file:

Width=1024
Height=768
Antialias=On
Sampling_Method=2
Antialias_Threshold=0.01
Antialias_Depth=4


I tried to change the max_trace_level up to 50, increase the Antialias Depth
until 7 and Antialias_Threshold down to 0.001 without success.

I use the 3.6 version of POV-ray.

If you have any idea to solve this problem tell me!

JO

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