POV-Ray : Newsgroups : povray.newusers : orthographic camera and conic_sweep object : orthographic camera and conic_sweep object Server Time
22 Feb 2024 23:38:17 EST (-0500)
  orthographic camera and conic_sweep object  
From: Warren
Date: 5 Nov 2017 07:05:00
Message: <web.59fefd5f68f4d962ca73ee9d0@news.povray.org>
Hi,
I have the following scene :

camera{orthographic
       location< 0, 20, 0>
       look_at <0,0,0>
       direction -y
       sky z
       up z * 4
       right x * 4}

light_source{<10,10,10>*100000 color srgb 1}

#declare green_col = srgb <8, 59, 4 >/256 ;
#declare brown_col = srgb <82, 62, 9> / 256 ;

#declare T_tent = texture{pigment{ dents color_map{
                                                    [0.0 green_col]
                                                    [0.2 green_col]
                                                    [0.21 brown_col]
                                                    [0.99 brown_col]
                                                    [1.0 green_col]
                                                   }
                                  scale 0.2 rotate 90*x
                                 }
                          normal{agate bump_size 0.25}
                          finish{specular 0.1 roughness 0.9 }
                         }

#declare Pyramid = prism{
                         conic_sweep linear_spline 1,0.5,
                         5 <-1,1>,<1,1>,<1,-1>,<-1,-1>,<-1,1>
                         rotate 180*x translate 1*y}

object{Pyramid texture{T_tent} }

-----------------------------------end of file

I get weird results when rendering. But when I change the camera settings with:

camera{orthographic
       location< 0.00001, 20, 0>
       look_at <0,0,0>
       direction -y
       sky z
       up z * 4
       right x * 4}

I get a render close to what I eventually want.

After a quick research, I found this post:
http://news.povray.org/povray.beta-test/thread/%3C3cd1c5ac%40news.povray.org%3E/

I have a hard time understanding why this is not a bug (the explanation of "
Thorsten Froehlich" especially); my camera isn't 'in' the conic_sweep object.

So , why must I add a small offset in the camera setting to get the expected
result instead of dark slopes for the pyramid ?


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