Since I'd probably get severely disciplined by the Bungie Webmaster if I scooped bungie.net, I thought I might reminisce a little bit today. Gearbox finally released the HEK (Halo Editing Kit for my parents), so now you all get to see what I got hired by Bungie to do three years ago. I've read some of the comments people have had over the quality and breadth of the tools in the HEK, and I thought I'd answer a few of them.
Firstly, if you have issues with the learnability of Sapien, you should understand that it was developed with the intent of always having a programmer (namely, me) on call to handle support issues. So, most of what is in Sapien is not documented anywhere. It also does not have any loading progress visualization, so if you see Sapien load up and then just sit there, it's (probably) not hung, it's just loading.
Secondly, if you're wondering why Sapien doesn't support more mapmaking features that you'd find in other game modding packages, namely, map creation, it's because the primary goal of Sapien was to be what 3dsmax and Maya are to artists for designers. That, and it's much more cost effective to buy an off the shelf 3d art package and write an exporter than to create a 3d modelling tool from scratch. It's unfortunate that currently you need to own MAX 4.x-5.x, but as I understand that, Gearbox is working on a solution to expand the range of apps that will support exporting Halo models.
As for the overall quality of Sapien, I'm surprised that it is still working almost three years after we shipped Halo 1. Ah well; I'm looking forward to seeing what the Halo mod community creates with the HEK. I might even post one or two tips and tricks to using Sapien in the future.