Scaling up a drawing

I Just tried a new technique for getting a drawing to full size for scaling up the various sections. All my work is drawn on cad so I linked up the computer to my projector in the workshop and moved the screen (steel Plate) on the overhead crane until the sizes on the drawing where equal to full size then I drew round it once onto the steel sheet for a pattern and once again onto paper to then cut out as templates. Easy peasy except when you turned round and got blinded