Introduction
have been attending the Early Days of the New South Wales Railways Workshops organised by the SCMRA for a few years. I have found these events to be particularly stimulating and always a good opportunity to learn more and share ideas. I can't imagine volunteering, but I can be easily persuaded, and I think this is what probably happened when I agreed to do a talk on Computer Aided Design (CAD) solid modelling techniques at the workshop. Although much of my modelling interest dates to before the turn of the 20th Century and my modern image stock dates
