Tim Attwood nous apporta ses lumieres en ce 2008/03/02 21:17:
> The center's a bit off, but this should work if
> you don't cut it too deep.
> 
> #local A = <-1,0,0>;
> #local B = <1,0,0>;
> #local C = <0,sqrt(2),0>;
> #local D = <0,0,1>;
> #local RAD = 0.075;
> 
> #declare tetra = mesh {
>    triangle {A,B,C}
>    triangle {B,C,D}
>    triangle {C,D,A}
>    triangle {D,A,B}
>    inside_vector (A+B+C+D)/4
>    translate <0,0,-RAD>
> }
> 
> #declare octaside = union {
>     sphere {A,RAD}
>     sphere {B,RAD}
>     sphere {C,RAD}
>     cylinder {A,B,RAD}
>     cylinder {C,B,RAD}
>     cylinder {A,C,RAD}
>     object{tetra}
>     rotate <45,0,0>
>     translate <0,0,-1>
> };
> 
> #declare pyramid = union {
>    object {octaside}
>    object {octaside rotate <0,90,0>}
>    object {octaside rotate <0,180,0>}
>    object {octaside rotate <0,270,0>}
> };
> 
> #declare octagon = union {
>    object {pyramid}
>    object {pyramid rotate <180,0,0>}
> };
> 
> 
Your octaedron is flatened verticaly. When viewed along an axis passing by two 
oposing summits, it should look square. As it is now, the projection will change 
depending on what pair of summits you chose.
Rotate is 45 degree around the Y axis, and all angles of the resultins image 
should be square angles. (I have the "real", solid, thing in my hand)

-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you read about an algorithm or 
datastructure and your first thought is: "How can I use this to speed up 
raytracing?"
Christoph Rieder

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