How can I calculate a multi-axis SCNVector4 rotation for a SCNNode?

Question

The SCNNode take a rotation using a SCNVector4, which has an angle (w) and a magnitude how that angle applies to each axis (x, y, z). For example, to rotate 45

Answer 1

You'll need to generate an SCNVector4 for each of the rotations, and then multiply them. Note that the order of operations matters!

http://www.cprogramming.com/tutorial/3d/rotationMatrices.html has a pretty good writeup of the math. Any OpenGL reference that deals with rotation matrices is worth a look too.