sub method
Subtracts v from this vector.
Implementation
Vector3 sub(Vector3 v, [w]) {
if (w != null) {
print('THREE.Vector3: .sub() now only accepts one argument. Use .subVectors( a, b ) instead.');
return subVectors(v, w);
}
x -= v.x;
y -= v.y;
z -= v.z;
return this;
}