I ran into this same problem when making my own data files. The data file is
starting at <0,0,0> and going off in each direction. Try making your
contained_by object like this instead:

 contained_by {sphere{<10,-10,-10>,10}}

ingo wrote:

> I'm playing with the MRI data of:
> ftp://www-itg.lbl.gov/pub/Whole.Frog/tomato/tomato.data.Z  (200 kB)
> The set has a dimension : 256x256x64 unsigned byte pixel.
> I'm having some problems with it, I think.
>
> difference {
>    isosurface {
>       function {
>            "data_3D_1",
>          <1.0>,
>          library "i_dat3d",
>          "tomato.data",
>          <256, 256, 64, 1>
>       }
>       contained_by {sphere{0,10}}
>       threshold 0.9
>       max_gradient 10
>    }
>    box {<-20,-20,-10>,<20,20,0>}
>    pigment { rgb 1}
> }
>
> When I render this it looks strangely symmetric, as if one segment is
> mirrored a few times.
> How big should the object be? The container has a radius of 10 and it looks
> like there is more. But when I increase the radius a sphere starts
> appearing in the middle.
> What am I doing wrong? Or are the data not suitable?
>
> Ingo
>
> --
> Photography: http://members.home.nl/ingoogni/
> Pov-Ray    : http://members.home.nl/seed7/

--
Samuel Benge

E-Mail: STB### [at] aolcom

Visit the still unfinished isosurface tutorial: http://members.aol.com/stbenge

Post a reply to this message