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 separate zip files with OBJ and STL files of the Ironman helmet pieces for others to use. Please credit the Replica Prop Forum and I, if you use! As I outline in Step Two, the build envelope of the printer that was used to produce this helmet was 10" x 14" x 8", so I had scaled the pieces to fit that and it is sort of a happy accident that it worked out. :)
Step 1: Modeling
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.