Create an equilateral triangle using three.js

Question

I am trying to create an equilateral triangle using three.js. What I am coming up with appears to be a bit too tall. I am defining my vertices like so:

new THREE.Vector3(0, 0, 0),
new THREE.Vector3(4, 0, 0),
new THREE.Vector3(2, 4, 0)

Here is a fiddle with what I have so far: http://jsfiddle.net/dkrotts/9d79ewff/. How can I modify this so I have a triangle with 3 equal sides?

http://stackoverflow.com/questions/2861904/how-to-find-coordinates-of-a-2d-equilateral-triangle-in-c — Alex McMillan, May 24 '15 at 04:58
I'm voting to close this question as off-topic because this is a problem of basic math, not a programming problem per se. You need to figure out how tall an equilateral triangle is relative to its sides (hint: use the Pythagorean theorem). — elixenide, May 24 '15 at 04:58

score 1 · Accepted Answer · answered May 24 '15 at 04:58

1

It looks a bit tall because it is. If you want each side to be length 4, the third vertex, the top one, isn't located at (2, 4, 0), it's located at (2, 3.4641, 0), 3.4641 being root 12.

drawTriangle(
  new THREE.Vector3(0, 0, 0),
  new THREE.Vector3(4, 0, 0),
  new THREE.Vector3(2, 3.4641, 0)
);

http://jsfiddle.net/9d79ewff/2/

answered May 24 '15 at 04:58

lhoworko

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Can this be extruded? – Agent Zebra Aug 14 '15 at 21:31
what do you mean by extruded? – lhoworko Aug 14 '15 at 21:32
It looks like it's rendering as a flat shape right now, can it be made into a 3d shape? Given some thickness? – Agent Zebra Aug 14 '15 at 21:51
Well it is a 3D shape right now, all points are just on the same plane. Remember that the the arguments passed into each vertex are (x, y, z) so to move the vertices off the plane, change the z coordinate. Take a look at http://jsfiddle.net/9d79ewff/5/ – lhoworko Aug 14 '15 at 22:02
That would be just moving the plane right? [I need to figure out how to extrude it](http://www.merriam-webster.com/dictionary/extrude) – Agent Zebra Aug 14 '15 at 22:09
Then you need to post a new question – lhoworko Aug 14 '15 at 22:09

Create an equilateral triangle using three.js

1 Answers1