Early last year, before The Avengers came out, I approached the rapid prototyping department at my company and asked if they would be able to help me produce a replica Ironman helmet. I had tried building the helmet with pepakura files produced by a member of the thereplicapropforum.com, but I found I did not have the time/patience/skill to sit and trim out hundreds of pieces of paper and reassemble them. This is my first instructable, but I wanted to share my process for anyone who has been interested in going this route. I took photos and screen caps along the way, but I may have missed a few steps that I'll just have to explain.
I've added a zip file with an STL of the Ironman helmet pieces for others to use. Please credit the Replica Prop Forum and I, if you use!
Step 1: Modeling
As I mentioned, I had gotten the pepakura helmet file from the RPF forum. I had also purchased a copy of the Pepakura software. With a full version that allows you to create files rather than just view, I exported the pepakura file as an OBJ which I could would with in Maya. The conversion process was easy, but because the pep file is meant for paper usage, it was relatively low resolution and had no thickness.
The first step, while the poly count was low, was to extrude the model inward to give the helmet thickness. Thickness is important, it provides stability to the final product which can be brittle when it is printed too thin. Because I planned on wearing this, (and probably walking into walls/doors/people) I wanted it to be thick enough the handle a bit of abuse. The final helmet varies in thickness because while the outside has grooves and ridges, I wanted the inside to be smooth. That way, the sides and bottoms of the grooves would have extra material around then to prevent fractures. The overall helmet averages between .125" and .25" thick.
When I was done adjusting the silhouette of the low poly helmet, I subdivided the model to provide a smoother finished surface. As you'll see later, I could have gone even further with this step.