Horror Mike’s Sunday Nooner presents Heavy Metal Movie Rare Animation stills, Rotoscope images.
Also, early Richard Corben Den video, news on Moebius – Jodorworsky’s The Incal plus great animation from a shuttered Incal project.
Heavy Metal: The Art of The Movie book is out of print but you can find some cheap deals on very good condition used copies here.  This invaluable resource shows the process of making the film with rotoscoping techniques, great cel animation photos and live action pics of the models used in the film.