I am pretty New to Povray and use Moray as well to generate scenes. But I
have a problem with the bicubic_patch.

What I wanted to do is generate a flat bicubic_patch where the start control
points are all at the same position. But it seems I loose the entire rounded
side and only display one the triangle. Even bringing the points close


This is the code I have

object { // BezPtch001
  object {
    bicubic_patch { type 1 flatness 0.0100 u_steps 3 v_steps 3,
      <1.000000, -2.000000, 0.000000>, <1.000000, -2.000000, 0.000000>,
<1.000000, -2.000000, 0.000000>, <1.000000, -2.000000, 0.000000>,
      <-2.000000, -1.000000, 0.000000>, <-1.000000, -1.000000, 0.000000>,
<0.000000, -1.000000, 0.000000>, <1.000000, -1.000000, 0.000000>,
      <-2.000000, 0.000000, 0.000000>, <-1.000000, 0.000000, 0.000000>,
<0.000000, 0.000000, 0.000000>, <1.000000, 0.000000, 0.000000>,
      <-2.000000, 1.000000, 0.000000>, <-1.000000, 1.000000, 0.000000>,
<0.000000, 1.000000, 0.000000>, <1.000000, 1.000000, 0.000000>
    }
  }
  material {
    Material2
  }
  translate  1.0*z
}

Bizarly enough moving some of the inner pounts up along the Z axis does
solve my problem for the most part. Like this.

object { // BezPtch001
  object {
    bicubic_patch { type 1 flatness 0.0050 u_steps 3 v_steps 3,
      <1.000000, -2.000000, 0.000000>, <1.000000, -2.000000, 0.000000>,
<1.000000, -2.000000, 0.000000>, <1.000000, -2.000000, 0.000000>,
      <-2.000000, -1.000000, 0.000000>, <-1.000000, -1.000000, 0.200000>,
<0.000000, -1.000000, 0.200000>, <1.000000, -1.000000, 0.200000>,
      <-2.000000, 0.000000, 0.000000>, <-1.000000, 0.000000, 0.200000>,
<0.000000, 0.000000, 0.200000>, <1.000000, 0.000000, 0.200000>,
      <-2.000000, 1.000000, 0.000000>, <-1.000000, 1.000000, 0.200000>,
<0.000000, 1.000000, 0.200000>, <1.000000, 1.000000, 0.200000>
    }
  }
  material {
    Material2
  }
  translate  1.0*z
}

Am I just stupid? Or is this normal? And if so Why?

Napivo

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