The gorgoneion was a seminar project in my very first semester of graduate school. We were learning about Greek temples and I decided to find out just how visible the Selinunte Temple C gorgoneion was with polychromy. To make it I printed a 1:1 scale drawing on graph paper, which I then projected onto a wall at the appropriate size. I traced it on bristol board and painted it according to the Museo Archeologico Regionale di Palermo reconstruction. The Carlos Museum was a meter or two short of Temple C but we had free access to it, so we hung it there. I had learned the bristol board technique from my mother, who used to make holiday decorations from stickers, but it was definitely challenging to do something on such a large scale!
The Parthenon Project was initiated by Bonna Wescoat, but I was brought on because of the gorgoneion above (as well as cosplay experience). There's a whole video here but suffice to say that my job was to create a 3D model of two frieze blocks, one white and one coloured, to compare with Rebecca Levitan's 2D panels. We used my projection technique, and I proceeded to cut the shapes out of foam board insulation. Those were glued to another board, then primed and coated with a plaster/glue mix. Cheese cloth was used for fabric details. They were then painted and hung on the Parthenon in Nashville. I had no experience making things out of foam board, but Emory Theatre was kind enough to give me a quick tutorial. Youtube taught me the rest.
The Parthenon photos are by K. Cupello.