Hi All,

while trying to track down a bug I found that negative scaling can
make objects disappear and was wondering (not being too well-versed in
POV) whether this is legal or not:


default { pigment { color rgb <1,1,0> }}

union { 
  sphere {
    <-1,0,0>,1
  }
  sphere { // Sphere101
    <1,0,0>,1
  }
  cylinder { // Cylndr034
    <-1,0,0>, <1,0,0>, 0.7 
  }
  scale 1 // <- Change to -1 and see the spheres disappear
}
                                

light_source
{
  0*x // light's position (translated below)
  color red 1.0  green 1.0  blue 1.0  // light's color
  translate <20, 40, 50>
}
                                
camera { location <0,0,6> look_at 0 }

The docs do not say anything about negative scaling. It is
inconsistent in that the cylinder does not disappear, though.

Thoughts?

- Lutz
  email : lut### [at] stmuccom
  Web   : http://www.stmuc.com/moray

Post a reply to this message