File:Midsphere.png

Original file (1,024 × 1,024 pixels, file size: 115 KB, MIME type: image/png)

Summary

Description
English: The midsphere of a polyhedron. The red circles indicate the points at which a cone, with its apex at a vertex, is tangent to the sphere. Rendered in POV-ray based on a different rendering of the same model from D. Eppstein (2005), Quasiconvex programming, Combinatorial and Computational Geometry, Goodman, Pach, and Welzl, eds., MSRI Publications 52, 2005, pp. 287-331, arXiv:cs.CG/0412046.
Source Own work
Author David Eppstein

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w:en:Creative Commons
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POV-ray source code

// Edge-tangent polytope and the sphere of edge tangencies
// David Eppstein, UC Irvine, 21 May 2001, modified 10 April 2011

global_settings {
   assumed_gamma 2.2
   ambient_light <3,3,3>
}

light_source { <-10, 35, -15> color <4,4,4> }

// light_source { <5, -10, -15> color <1.5,1.5,1.5> }

// perp: <5,1,-6> <1,1,1> <7,-11,4>
// perp: <5,2,-2> <0,1,1> <4,-5,5>

#declare p=<1,1,1>/sqrt(3);
#declare q=<7,-11,4>/sqrt(186);
camera {
   location  <5,1,-6>
   look_at   <0.5, 0, 0>
   up -q*0.65
   right p*0.65
   translate <-0.1,0,-0.5>
   rotate <0,-5,0>
}

sphere { <0.0, 0.0, 0.0>, 2
	texture {
		finish {
			specular 1
			roughness 0.002
			ambient 0.1
			diffuse 0.05
			reflection 1
			phong 0.3
			phong_size 60
		}
		pigment { color rgbf<0.2, 0.2, 1.5, 0.7> }
	}
}

#declare P_Surf =
texture {
    finish {
       ambient 0.2
       diffuse 0.2
    }
    pigment { color red 1 green 1 blue 1 }
}

polygon {
    4,
    <0,2,-2>,<0,2,2>,<2,0,1>,<2,0,-1>
    texture { P_Surf }
}

polygon {
    4,
    <0,2,-2>,<0,2,2>,<-2,0,1>,<-2,0,-1>
    texture { P_Surf }
}

polygon {
    4,
    <0,-2,-2>,<0,-2,2>,<2,0,1>,<2,0,-1>
    texture { P_Surf }
}

polygon {
    4,
    <0,-2,-2>,<0,-2,2>,<-2,0,1>,<-2,0,-1>
    texture { P_Surf }
}

polygon {
	3,
	<0,2,2>,<2,0,1>,<0,-2,2>
	texture { P_Surf }
}

polygon {
	3,
	<0,2,-2>,<2,0,-1>,<0,-2,-2>
	texture { P_Surf }
}

polygon {
	3,
	<0,2,2>,<-2,0,1>,<0,-2,2>
	texture { P_Surf }
}

polygon {
	3,
	<0,2,-2>,<-2,0,-1>,<0,-2,-2>
	texture { P_Surf }
}

#declare P_Ring =
texture {
    finish {
       ambient 0.3
       diffuse 0.3
    }
    pigment { color red 1 green 0 blue 0 }
}

torus {
	2/sqrt(2), 0.013
	texture { P_Ring }
	rotate <-45,0,0>
	translate <0,1,-1>
}

torus {
	2/sqrt(2), 0.013
	texture { P_Ring }
	rotate <45,0,0>
	translate <0,1,1>
}

torus {
	2/sqrt(2), 0.013
	texture { P_Ring }
	rotate <-45,0,0>
	translate <0,1,-1>
	rotate <180,0,0>
}

torus {
	2/sqrt(2), 0.013
	texture { P_Ring }
	rotate <45,0,0>
	translate <0,1,1>
	rotate <180,0,0>
}

torus {
	2*sqrt(1/5), 0.013
	texture { P_Ring }
	rotate <90,-asin(2/sqrt(5))*180/pi,0>
	translate <8/5,0,-4/5>
}

torus {
	2*sqrt(1/5), 0.013
	texture { P_Ring }
	rotate <90,asin(2/sqrt(5))*180/pi,0>
	translate <8/5,0,4/5>
}

torus {
	2*sqrt(1/5), 0.013
	texture { P_Ring }
	rotate <90,-asin(2/sqrt(5))*180/pi,0>
	translate <8/5,0,-4/5>
	rotate <180,0,0>
}

torus {
	2*sqrt(1/5), 0.013
	texture { P_Ring }
	rotate <90,asin(2/sqrt(5))*180/pi,0>
	translate <8/5,0,4/5>
	rotate <180,0,0>
}

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Date/TimeThumbnailDimensionsUserComment
current20:49, 10 April 2011Thumbnail for version as of 20:49, 10 April 20111,024 × 1,024 (115 KB)David Eppstein{{Information |Description ={{en|1=The midsphere of a polyhedron. The red circles indicate the points at which a cone, with its apex at a vertex, is tangent to the sphere. Rendered in POV-ray based on a different rendering of the same

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