title: Is there a way I can create a Path or Curve to use for TubeGeomety(path,...) from an existing geometry's points/vertices array?
body: <p>I'm very new to both three.js &amp; to js in general.
  1st I select a polyHedron geometry with a dat.gui checkbox
  which renders say a tetrahedron. these selections work.
  I also have a dat.gui checkbox to either phongfill or wireframe render. 
  I initially wanted just a wireframe type mesh but not with all of the internal triangles. I found the edgesgeometry() function which draws pretty much what I want(hard edges only). there is however a known issue with linewidth not working in windows anymore. all lines drawn as strokeweight/width 1.  </p>
  
  <p>I'd like to use tubeGeometry() to draw tubes of whatever radius as opposed to 1weight lines. I know I'll have to draw something such as a sphere at/over the connection vertices for it to not look ridiculous. </p>
  
  <pre><code>geo = new THREE.TetrahedronBufferGeometry(controls0.Radius,controls0.Detail);
  ...
  egeo = new THREE.EdgesGeometry( geo );
  lmat = new THREE.LineBasicMaterial({ color: 0x0099ff, linewidth: 4 });
  ph = new THREE.LineSegments( egeo, lmat );
  scene.add(ph);
  ....
  </code></pre>
  
  <p>playing around in the console I found some geometry/bufferGeomery arrays that are likely the vertices/indices of my selected X-hedron as their sizes change with type(tetra/icosa etc) selection &amp; detail increase/decrease:</p>
  
  <pre><code>//p = dome.geometry.attributes.uv.array;
  p = egeo.attributes.position.array
  //p = geo.attributes.uv.array
  ...
  var path = new THREE.Curve();
  path.getPoint = function (t) {
  // trace the arc as t ranges from 0 to 1
  var segment = (0 - Math.PI*2) *t;
  return new THREE.Vector3( Math.cos(segment), Math.sin(segment), 0);
  };
  
   var geomet = new THREE.TubeBufferGeometry( path, 10, 0.2, 12, false );
   var mesh = new THREE.Mesh( geomet, mat );
   scene.add( mesh );
  </code></pre>
  
  <p>from above the tubeGeometry() draws fine separately as well but with the "path" made by that curve example. How can I use the vertices from my tetrahedron for example to create that "path" to pass to tubegeometry() ?</p>
  
  <p>maybe a function that creates "segment vectors" from the vertices ? 
  I think it needs other properties of curve/path as well ?
  I'm quite stuck at this point.</p>
  
  <p>ANY Help, suggestions or examples would be greatly appreciated !
  thanks.</p>