About SCNMatrix4 in Chapter 6

I don’t know about the SCNMatrix4. Why is the (m41, m42, m43) of SCNMatrix4 be the node’s position ? About adding force to the dices, what is the meaning of the direction’s formula?

let direction = SCNVector3(-(distance * 2.5) * transform.m31, -(distance * 2.5) * (transform.m32 - Float.pi / 4), -(distance * 2.5) * transform.m33)

Thanks.

@chrislanguage Can you please help with this when you get a chance? Thank you - much appreciated! :]

Up question. Completely not understand of using of SCNMatrix4.

@chrislanguage Do you have any feedback about this? Thank you - much appreciated! :]

One more up question.