I'm learning how to be a competent low-poly modeler in 3ds max. I've been working on the helmet above for about an hour now. I started with a tube object that I made into a bell shape by scaling the vertices. I've started to cut away at the front so that the guy inside can see. I did this by selecting and deleting both the outward-facing and inward-facing polygons of that section of the tube. So far so good. My question: I now have a bunch of edges that I could like to cap with faces to make a solid water-tight object. How do I do that? I found the Cap Holes modifier - which works on the top of the helmet, but not for the rim. I also found the Select All Open Edges button - it seems like I am just missing the final step.

go to the polygon sub-selection level(Editable Poly) and click on the create button. then go clicking on the vertices to create a polygon. look at the documentation for futher details.

Another way is "create face", I think this is in Face editing mode of Editable Poly. You click the verticies that surround the gap, in clockwise order, and when you click on the first one again, it creates the face over the hole.

(Something like that, it's been a while)