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andfaulkner/AngleBetween3PointsIn3DSpace.js

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  1. andfaulkner revised this gist Feb 13, 2019. 1 changed file with 5 additions and 0 deletions.
    5 changes: 5 additions & 0 deletions AngleBetween3PointsIn3DSpace.js
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    Original file line number Diff line number Diff line change
    @@ -52,3 +52,8 @@ const angleBetween3DCoords = (coord1, coord2, coord3) => {
    // Round result to 3 decimal points and return
    return Math.round(angle * 1000) / 1000;
    };

    // Usage:

    angleBetween3DCoords({x: 1, y: 0, z: 0}, {x: 0, y: 0, z: 0}, {x: 0, y: 1, z: 0});
    // => 90
  2. andfaulkner renamed this gist Feb 13, 2019. 1 changed file with 0 additions and 0 deletions.
    0 gistfile1.txt → AngleBetween3PointsIn3DSpace.js
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    File renamed without changes.
  3. andfaulkner created this gist Feb 13, 2019.
    54 changes: 54 additions & 0 deletions gistfile1.txt
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,54 @@
    /**
    * Calculate angle between 3 points in 3D space.
    * Note: assumes we want 1 vector to run from coord1 -> coord2, and the other
    * from coord3 -> coord2.
    *
    * @param {x: number; y: number; z: number} coord1 1st (3D) coordinate
    * @param {x: number; y: number; z: number} coord2 2nd (3D) coordinate
    * @param {x: number; y: number; z: number} coord3 3rd (3D) coordinate
    *
    * @return {number} Angle between the 3 points
    */
    const angleBetween3DCoords = (coord1, coord2, coord3) => {
    // Calculate vector between points 1 and 2
    const v1 = {
    x: coord1.x - coord2.x,
    y: coord1.y - coord2.y,
    z: coord1.z - coord2.z,
    };

    // Calculate vector between points 2 and 3
    const v2 = {
    x: coord3.x - coord2.x,
    y: coord3.y - coord2.y,
    z: coord3.z - coord2.z,
    };

    // The dot product of vectors v1 & v2 is a function of the cosine of the
    // angle between them (it's scaled by the product of their magnitudes).

    // Normalize v1
    const v1mag = Math.sqrt(v1.x * v1.x + v1.y * v1.y + v1.z * v1.z);
    const v1norm = {
    x: v1.x / v1mag,
    y: v1.y / v1mag,
    z: v1.z / v1mag,
    };

    // Normalize v2
    const v2mag = Math.sqrt(v2.x * v2.x + v2.y * v2.y + v2.z * v2.z);
    const v2norm = {
    x: v2.x / v2mag,
    y: v2.y / v2mag,
    z: v2.z / v2mag,
    };

    // Calculate the dot products of vectors v1 and v2
    const dotProducts = v1norm.x * v2norm.x + v1norm.y * v2norm.y + v1norm.z * v2norm.z;

    // Extract the angle from the dot products
    const angle = (Math.acos(dotProducts) * 180.0) / Math.PI;

    // Round result to 3 decimal points and return
    return Math.round(angle * 1000) / 1000;
    };