Which build of obj2map was that with? Maybe try the beta in post 66; I remember fixing a bug with a similar stack trace as what you posted. 

Both versions (1 and 1.1.1) did the same thing. I'll try this beta (extrusion\grid align locked it up to a "not responding" state), so I'll try the other combinations and let you know 

Standard\axis aligned : Stuck on "Adding brush 0 to map" - Not Responding -..took 40 mins to get the brush 1

extrusion\axis aligned : Stuck on "Adding brush 0 to map" - Not Responding

extrusion\no axis aligned : Unhandled Exception
System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index

Spikes\axis aligned : Stuck on "Adding brush 0 to map" - Not Responding

Spikes\no axis aligned : Unhandled exception - The path is notof a legal form. 

I'm going to try 3DSmax 2009 and see what happens with THOSE OBJ's. 

Ok, installed 3dsmax 2009, Re-ripped and exported the OBJ again (successfully). Same errors as before. Must be Windows 10 related. I'll try on other PC's around the home when I get a chance 

OBJ is an ascii format. Open it and check it. 

Or post the file here. Maybe someone can figure out what's going on. 

Summary:
Vertices: 33410
Faces: 12
Brushes: 202

I mean what were the stats in Max. Also the above numbers don't make any sense. 12 faces with 33k verts?

As a reference, I was successfully able to convert a mesh with 5k triangles and 2.5k verts into a map file from Max2011 (sorry, i said 2009 earlier). 

Try to triangulate whole model and see if it works. 

I've uploaded the file to my ftp. Now please note, this is a private project, and the contents DO infringe copyright. So please delete it once you're done, as it's not mine to distribute. I'll be deleting the file off the ftp in 24 hours.
www.leviathan.net.au/nuke-rebuilt.obj 

I have a hard time seeing it ending up as a map file at all. 

That's what the OBJ converter does from 3DSmax 2009 and 2016. It loads fine into Win10 3D builder and blender, but as far as map conversion..I think i've hit a wall. (so to speak) :) 

Mesh is just a massive cloud of orphaned vertices.

I'm all for experimental maps and whatnot, but... 

Try zooming out 

I looked at that OBJ. That's never going to convert. That's insane. 

I'm guessing from the googie look and file name it's something Fallout related? 

I mean, maybe break it down into smaller chunks or something but :

(a) it's absolutely immense - MODO tells me there's ~163,000 triangles

(b) there's a mountain of triangles (none of which are anywhere near a grid, I'd wager)

(c) I think it broke when loading into MODO, to be honest, as there are missing polys everywhere, tons of overlapping stuff, etc.

Just ... bleh. 

The idea behind this app is that you're modeling with Quake in mind. :) 

I loaded it into MODO and I had to flip it upside down to make it look right. Then 90% of the tris are triplicated, so ran a poly.unify on those.
Even then it's still a mess of weird orphan objects floating in the middle of nowhere, partial houses, and broken terrain. 

Yep, I totally agree with all of you. It's a bloody mess. Just needed more opinions before I threw it in the "too bloody hard" basket.
Anyway..Treyarch just announced mapping tools for Black Ops 3, so making new Prefabs is the next project instead. Thanks for all your questions\answers on this problem. 

Eric, can you add your source code into the main repository? If it's there, I apologize, I'm not too familiar with this stuff ... but I don't see it.

Anyway, bug report ... you can't leave the MAP filename blank anymore. That was useful for people who only wanted to copy the results to the clipboard. If you leave the MAP filename blank, it crashes. 

Err ... I think I see it now, you DO have code in there. Stupid SourceTree... 

Yeah- all my code is up on bitbucket, I was working on my own fork here: https://bitbucket.org/ericwa/obj-2-map/commits/all , but khreathor pulled all of my texturing stuff into the "wip" branch of the main repo. 

someone has a favorite head shape 

yeah I merged it into wip branch, because I wanted to keep old stable source. It will be good to make some radio button where you can choose between old and new method, classic MAP and Valve 220 MAP. What do you think?