wayne461 wrote:
> Jim Charter <jrc### [at] msncom> wrote:
> 
>>Not bad guess at the texture.  He oiously also layed in some scuffs with
>>a large bumps or dents of some such.
>>
>>Most of his code there looks straightforward enough to me.  He is using
>>a patched version that circulated for awhile that allowed you to replace
>>the #declare with a $ sign.  The eval_3d_spline macro is pretty tame as
>>I recall.  But all of that is obviously just a way to get the raised
>>seams.    But what we don't have is the actually spline definition which
>>is at the heart of the path of the seam on the sphere.
>>
>>I recall there was a nice tutorial circulating in the Wings3D community
>>that demonstrated how to model the shape of that style of seam (which
>>exists on other sports balls too)  It took advange of how subdivision
>>smoothing worked against a cube as I recall.  But I can no longer find it.
> 
> Jim,
> So do you know if the eval_3d_spline macro converted into POVRAY 3.6
> anywhere?
> 
> Do we really even need a spline though?  I thought that with some
> well-placed pieces of tori (plural or torus?) and the blob function we
> could add the seams?  The placement of the red stitches was what I thought
> would be the hardest because I don't know easily who to place them along
> the seam defined by the tori.
> 
> 
> 
It might be possible to approximate the effect with torii and maybe 
cylinders at the joins but a spline does seem the way to go.  Torii 
curve in a plane whereas this seam moves smoothly through three 
dimensions.  All the rest is relatively easy (depending on the degree of 
   resolution you want) if that curve could be defined.

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