CODEWITHSUNDEEP
javascriptthree.js
iggybbz
iggybbz

Reputation: 63

Three.js PolyhedronGeometry Vertices Position

So I am trying to create my own shape with PolyhedronGeometry

rough sketch: enter image description here

I'm running into problems. Specifically I'm trying to attach this shape onto a sphere, so using some formulas I came up with the following vertices:

[ -0.6495190528383289, -0.09943689110435831, 0.36157613954394185, 
   0, -0.09943689110435831, 0.7433789778353299, 
   0.6495190528383289, -0.09943689110435831, 0.36157613954394185,
   0.3897114317029973, -0.39774756441743325, 0.7231522790878837, 
   0, -0.5966213466261499, 0.5947031822682639, 
  -0.3897114317029973, -0.39774756441743325, 0.7231522790878837 ]

then for the face indices I have:

[ 5,4,1, 5,1,0, 2,1,3, 4,3,1, 0,1,2, 0,4,5, 2,3,4 ]

When I add spheres as debugging points, they appear at the right place, but no matter how I adjust the vertices/faces, some of the positions are incorrect:

enter image description here

  1. Is order important for the faces?
  2. Why does my polyhedron not draw correctly?

Upvotes: 2

Views: 1057

Answers (1)

stdob--
stdob--

Reputation: 29172

The problem is that the lengths of the original vectors are not equal to each other, so that the construction of their projections on the figure are not the same scope. And maybe, you specify the radius of the sphere wrong.

For example, the length of the first vector in the set:

(new THREE.Vector3( 
                    -0.6495190528383289, 
                    -0.09943689110435831, 
                    0.36157613954394185 )
).length() === 0.75

A length of the last vector in the set:

(new THREE.Vector3(
                    -0.3897114317029973, 
                    -0.39774756441743325, 
                    0.7231522790878837 )
).length() === 0.9127033163903814

If you set a radius equal to the PolyhedronGeometry of the length of the first vector, the latter vector is outside the sphere of this radius. If you set a radius equal to the PolyhedronGeometry of the length of the last vector is the first vector is inside the sphere.

Upvotes: 2

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