I thought forum readers might be interested in this. Scott Johnson has a new article on www.gamasutra.com that discusses matrix transformations in detail. It covers hierarchies of transforms, and row vs. column conventions. In my opinion, it is a VERY good article if you are having trouble with matrices and transforms. www.gamasutra.com/features/20020510/johnson_01.htm You will have to register on www.gamasutra.com to read the article, but registration is free and the content is beneficial. (Actually, much of the content is straight out of Game Developer Magazine.) Graham Rhodes Senior Scientist Applied Research Associates, Inc.