add method
Adds v to this vector.
Implementation
Vector3 add(Vector3 v, [w]) {
if (w != null) {
print('THREE.Vector3: .add() now only accepts one argument. Use .addVectors( a, b ) instead.');
return addVectors(v, w);
}
x += v.x;
y += v.y;
z += v.z;
return this;
}