POV-Ray : Newsgroups : povray.newusers : Cutaway of helix isosurface leaving unwanted artifacts Server Time
11 Nov 2024 04:41:49 EST (-0500)
  Cutaway of helix isosurface leaving unwanted artifacts (Message 1 to 3 of 3)  
From: planiform
Subject: Cutaway of helix isosurface leaving unwanted artifacts
Date: 13 Nov 2003 13:15:01
Message: <web.3fb3c9faf4909c64a09175c60@news.povray.org>
Hello all.  This is my first post.  Hope I'm following protocol.

Below is code I wrote for the difference between a helix isosurface and a
box.  As you can see the box is removing the section of helix but leaving
an artifact.  Can anyone explain how to fix this?  Thanks in advance.






#include "colors.inc"
#include "functions.inc"

global_settings {
        assumed_gamma 1.3
        max_trace_level 5}


camera { location <3,3,-4>
         look_at <1,0,0>}


light_source {<10, 20, -30> color Gray25}


sky_sphere {pigment {gradient y color_map {[0, 1  color Gray50 color
Gray80]}}}


plane { y, -1.25 pigment {checker color Gray40 color Gray80 scale <1, 1,
10000> rotate y*45} finish { ambient 0.45 }}


#declare IsoTexture = texture { pigment { rgb <1.0, 0.8, 0.5> } finish {
phong 0.6 phong_size 250 } }


#declare spring =
         isosurface {
                        function { f_helix1(x,y,z, 1, 20, 0.0875, 0.75, 1,
1, 0) }
                  contained_by { box { <-1, -2.2, -1>, <2, 2, 2> } }
                  max_gradient 5
                  texture { IsoTexture }
                  no_shadow
                  scale <1,1,-1>
                  rotate <0,0,90>
                         }


#declare cutaway =
        box { <-10,0,0> <20,100,-100> pigment {White}
          }


difference{
        object{spring}
        object{cutaway}
        }


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From: caffeinebill
Subject: Re: Cutaway of helix isosurface leaving unwanted artifacts
Date: 13 Nov 2003 14:05:02
Message: <web.3fb3d5cdec150afcd6c93cf30@news.povray.org>
planiform wrote:
>Hello all.  This is my first post.  Hope I'm following protocol.
>
>Below is code I wrote for the difference between a helix isosurface and a
>box.  As you can see the box is removing the section of helix but leaving
>an artifact.  Can anyone explain how to fix this?  Thanks in advance.

In the documentation on Isosurface objects, it specifically mentions your
problem.  It is related to performing CSG operations on isosurfaces.  Check
out the following link and look for max_trace and all_intersections.

http://www.povray.org/documentation/view/169/

Bill


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From: planiform
Subject: Re: Cutaway of helix isosurface leaving unwanted artifacts
Date: 13 Nov 2003 14:40:00
Message: <web.3fb3dd37ec150afca09175c60@news.povray.org>
caffeinebill wrote:
>planiform wrote:
>>Hello all.  This is my first post.  Hope I'm following protocol.
>>
>>Below is code I wrote for the difference between a helix isosurface and a
>>box.  As you can see the box is removing the section of helix but leaving
>>an artifact.  Can anyone explain how to fix this?  Thanks in advance.
>
>In the documentation on Isosurface objects, it specifically mentions your
>problem.  It is related to performing CSG operations on isosurfaces.  Check
>out the following link and look for max_trace and all_intersections.
>
>http://www.povray.org/documentation/view/169/
>
>Bill
>

Wow!  Thanks so much for the help; that fixed it nicely.  When all else
fails, read the directions AGAIN!


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