Jan Walzer <jan### [at] lzernet> wrote:
: Would it help, to tesselate this into four triangles by adding another vertex
: in the center of the polygon ?
: would this avoid the distortion or is this only a "better error" (you know
: what I mean) ...

  As you guessed, it doesn't get rid of the error. The "stripes" in the
texture will, when applied to a triangle, always be parallel along the
surface of the triangle, although they shouldn't, due to the shape of the
polygon. This is a flaw in the classical texture mapping algorithm.

: If so, what is the correct procedure, to avoid this ?

  In a more advanced triangle texture mapping algorithm it is possible to
specify a texture stretching value which changes along the surface of the
triangle, and this effectively gets rid of this artifact. This algorithm has
a name, but I don't remember what it is.

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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