Math

Angle between two vectors

vex

// Normalize the vectors first!
float angleBetween ( vector v1; vector v2 ) {
    // define up vector
    vector up = {0.0, 1.0, 0.0};

    float angle = acos(dot(v1, v2));
    int firstHalf = sign(dot(v2, cross(up, v1))) >= 0;
    angle = firstHalf ? angle : 2 * PI - angle;

    return degrees(angle);
}

Math constants : Epsilon

Check /opt/hfs20.0/houdini/vex/include math.h

vex

#define M_TOLERANCE  0.0001