xeokit Quaternion Math Utilities

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Utilities for representing and manipulating 3D rotations with quaternions.

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This module provides quaternion primitives (typed-array friendly) plus common conversion and composition helpers used throughout xeokit math:

• Build quaternions from Euler angles, rotation matrices, angle–axis, or by aligning one direction vector to another.
• Convert quaternions back to Euler angles, matrices, or angle–axis form.
• Apply quaternion rotations to vectors and combine rotations via quaternion multiplication.

Quaternions are stored as [x, y, z, w], where (x, y, z) is the vector part and w is the scalar part. Most functions accept either typed arrays (Float32Array / Float64Array) or plain 4-tuples, and many support an optional destination parameter to avoid allocations.

Installation

npm install @xeokit/sdk
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Usage

Import the helpers you need:

import {
  identityQuat,
  eulerToQuat,
  quatToEuler,
  quatToRotationMat4,
  mat4ToQuat,
  mulQuats,
  vec3ApplyQuat,
  quatToAngleAxis,
  angleAxisToQuaternion
} from "@xeokit/sdk/math/quat";
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Create a quaternion from Euler angles

const q = eulerToQuat([30, 45, 0], "XYZ"); // degrees
console.log("Quaternion:", q);
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Rotate a vector with a quaternion

const v = [1, 0, 0];
const rotated = vec3ApplyQuat(q, v);
console.log("Rotated vector:", rotated);
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Convert between quaternion and matrix

const m = quatToRotationMat4(q, new Float64Array(16));
const q2 = mat4ToQuat(m);
console.log("Round-trip quaternion:", q2);
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Angle–axis conversion

const aa = quatToAngleAxis(q); // [x, y, z, angleRadians]
const q3 = angleAxisToQuaternion(aa);
console.log("Angle–axis:", aa, "Back to quat:", q3);
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