I'm not sure what shape you want it to be, but 2 of your corner points are 
in the same place. The points in a bicubic patch follow this order:

A, B, C, D,
E, F, G, H,
I, J, K, L,
M, N, O, P

You can imagine that's a top-down view of the patch, the points A D M and P 
are the corners, all the ones in between are control points. In yours A and 
D have the same position <1.000000, -2.000000, 0.000000>, hence it appears 
triangular.

A simple square one would be:
<0,0,0>, <1,0,0>, <2,0,0>, <3,0,0>,
<0,1,0>, <1,1,0>, <2,1,0>, <3,1,0>,
<0,2,0>, <1,2,0>, <2,2,0>, <3,2,0>,
<0,3,0>, <1,3,0>, <2,3,0>, <3,3,0>

That might be an easier thing to start with. Note the control points are 
evenly spread between the corners so you get a nice distribution of polygons 
when pov processes the patch. Also I wouldn't bother using flatness, it's 
not really necessary unless your patch is really slow to draw.

-- 
Tek
http://evilsuperbrain.com

"Napivo" <Nap### [at] yahoofr> wrote in message 
news:web.45a761af6f5b502e3cd9c0860@news.povray.org...
>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
> together doesn't solve my problem.
>
> 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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