The rotation operation is not commutative.
In other words the order of Successive Rotations is significant, for example
This gives 90 degree rotation about Z axis,
whereas
This gives 90 degree rotation about y axis (first 2 lines cancel out)
metadata block 

see also: 

Correspondence about this page  
Book Shop  Further reading. Where I can, I have put links to Amazon for books that are relevant to the subject, click on the appropriate country flag to get more details of the book or to buy it from them. 
3D Math Primer  Aimed at complete beginners to vector and matrix algebra. 
This site may have errors. Don't use for critical systems.
Copyright (c) 19982015 Martin John Baker  All rights reserved  privacy policy.