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Graphics and Visualization Wolfram Language

Why am I seeing a Cone instead of a bicone?

Janos Lobb

Posted 4 years ago

Clear["Global`"] ( Bicone properties ) r = 1; orig = {x1, y1, z1}; vertex1 = {x2, y2, z2}; vertex2 = {x2, y2, -z2}; cone1 = Cone[{orig, vertex1}, r]; cone2 = Cone[{orig, vertex2}, r]; bicone = {cone1, cone2}; Graphics3D[bicone] /. {orig -> {0, 0, 0}, vertex1 -> {0, 0, 1}, vertex2 -> {0, 0, 1}} I see just a cone instead of a bicone although in vertex2 the z-coordinate is negative. The result is the same either I apply the rule inside or outside of Graphics3D. Attachments:* Packing with cones.nb

Clear["Global`*"]
(* Bicone properties *)
r = 1;
orig = {x1, y1, z1};
vertex1 = {x2, y2, z2};
vertex2 = {x2, y2, -z2};
cone1 = Cone[{orig, vertex1}, r];
cone2 = Cone[{orig, vertex2}, r];
bicone = {cone1, cone2};
Graphics3D[bicone] /. {orig -> {0, 0, 0}, vertex1 -> {0, 0, 1}, 
  vertex2 -> {0, 0, 1}}

I see just a cone instead of a bicone although in vertex2 the z-coordinate is negative. The result is the same either I apply the rule inside or outside of Graphics3D.

POSTED BY: Janos Lobb

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Gianluca Gorni

Gianluca Gorni, University of Udine

Posted 4 years ago

The two cones are identical. Did you mean `vertex2 -> {0, 0, -1}`?

POSTED BY: Gianluca Gorni

Janos Lobb

Posted 4 years ago

Yes, that is what I was thinking. Thanks a lot.

POSTED BY: Janos Lobb

Oliver Seipel

Posted 4 years ago

The variables x1,y1,z1,x2,y2,z2 are never addressed. ommit x1,y1,z1,x2,y2,z2: r = 1; cone1 = Cone[{orig, vertex1}, r]; cone2 = Cone[{orig, vertex2}, r]; bicone = {cone1, cone2}; Graphics3D[bicone, PlotRange -> All] /. {orig -> {0, 0, 0}, vertex1 -> {0, 0, 1}, vertex2 -> {0, 0, -1}} or address x1,y1,z1,x2,y2,z2 directly: r = 1; orig = {x1, y1, z1}; vertex1 = {x2, y2, z2}; vertex2 = {x2, y2, -z2}; cone1 = Cone[{orig, vertex1}, r]; cone2 = Cone[{orig, vertex2}, r]; bicone = {cone1, cone2}; Graphics3D[bicone, PlotRange -> All] /. {x1 -> 0, y1 -> 0, z1 -> 0, x2 -> 0, y2 -> 0, z2 -> 1}

The variables x1,y1,z1,x2,y2,z2 are never addressed.

ommit x1,y1,z1,x2,y2,z2:

r = 1;
cone1 = Cone[{orig, vertex1}, r];
cone2 = Cone[{orig, vertex2}, r];
bicone = {cone1, cone2};
Graphics3D[bicone, PlotRange -> All] /. {orig -> {0, 0, 0}, 
  vertex1 -> {0, 0, 1}, vertex2 -> {0, 0, -1}}

or address x1,y1,z1,x2,y2,z2 directly:

r = 1;
orig = {x1, y1, z1};
vertex1 = {x2, y2, z2};
vertex2 = {x2, y2, -z2};
cone1 = Cone[{orig, vertex1}, r];
cone2 = Cone[{orig, vertex2}, r];
bicone = {cone1, cone2};
Graphics3D[bicone, PlotRange -> All] /. {x1 -> 0, y1 -> 0, z1 -> 0, 
  x2 -> 0, y2 -> 0, z2 -> 1}

POSTED BY: Oliver Seipel

Janos Lobb

Posted 4 years ago

Thanks. Ten minutes after I sent, the tantus fell off. ;-)

POSTED BY: Janos Lobb

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