POV-Ray : Newsgroups : povray.binaries.images : Question regarding mesh and texture_list : Question regarding mesh and texture_list Server Time
29 Nov 2022 13:24:13 EST (-0500)
  Question regarding mesh and texture_list  
From: BayashiPascal
Date: 24 May 2021 00:30:00
Message: <web.60ab28c3e105b2bda3e088d5e0f8c582@news.povray.org>
Hi everyone,
I have a question regarding texture_list applied to mesh of very small size.
I've noticed that in such case artifacts appear in the texture. I can avoid the
problem by scaling up the input mesh (generated by another app), and scaling it
back down in the POV-Ray script, but if possible I'd like to avoid that.
I guess this is a problem related to numerical accuracy, so maybe there is a
parameter somewhere that would help ?? Or, is there something else I'm not aware
of, and doing wrong ?
Please find below a small script reproducing the problem. In the rendered image,
both triangles should look the same. The left one has initial coordinates of
order 0.01, while the right one has initial coordinates of order 0.1 and is
scaled by 0.1. These doesn't look to me as unreasonably small values...
(The same artifact occurs if using mesh2)

Thanks in advance for your help.
Pascal



#version 3.7;

#declare tex0 = texture {pigment{rgb x}};
#declare tex1 = texture {pigment{rgb y}};
#declare tex2 = texture {pigment{rgb z}};

#declare meshA = mesh {
  triangle{
    <0.7,0.06,-0.06> ,<0.66,0.06,-0.1> ,<0.7,0.06,-0.1>
    texture_list {tex0 tex1 tex2}
  }
}

#declare meshB = mesh {
  triangle{
    <0.07,0.006,-0.006> ,<0.066,0.006,-0.01> ,<0.07,0.006,-0.01>
    texture_list {tex0 tex1 tex2}
  }
}

camera { location 0.01 look_at 0.005*x }
light_source { 1 color rgb 1 }

object {
  meshA
  scale 0.1
  translate <0.07,0.006,-0.006>*-1
}

object {
  meshB
  translate <0.07,0.006,-0.006>*-1
  translate x*0.01
}


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Attachments:
Download 'bugmeshtexture.png' (15 KB)

Preview of image 'bugmeshtexture.png'
bugmeshtexture.png


 

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