OaR - Loop Mod


Current Status: Finished: https://www.dropbox.com/s/q8ik53e37wgefxt/LoopMod.zip

Now available on ModDB: http://www.moddb.com/mods/black-mesa-on-a-rail-loop-mod


Howdy everyone!

I am working on a mod for Black Mesa called the “Loop Mod”. What this mod does is add some new sections of track to the very first map for On a Rail.

At the very beginning of the original Half Life’s On a Rail chapter, the player was presented with some looped hallways to navigate as they tried to find their way around, eventually finding the crane controls and being able to move on to the next section. At the time though the layout for this idea was confusing and nonsensical at best, and as a result was left out entirely from the Black Mesa mod.

I intend to return to the spirit of this section (without replicating the needless complexity, and – in general – make it easier to follow and understand).


This mod will add new sections to the map bm_c2a2a.

Integrated into what was already there, the player will first go up the right shaft past the houndeyes, then will turn right into this loop addition. While there, they will run into an office where they can switch the tracks back at the junction. They will then be able to ride through the junction and make their way to the electric pool puzzle.


Other info

Background – I have some experience in mapping for Portal 2, having created a few levels over the past couple of years (most of which are unfinished and will probably not see the light of day). Therefore, I believe that I have the skills necessary to create these new sections while keeping with the style set by the devs in the original map.

Compatibility – As I am sure many of you know, there is currently another mod for On a Rail named Oar Uncut. If you haven’t checked it out already, do so. It’s an excellent mod. If you have installed his mod or are planning to install it, I will be providing support for the mod. At release, I will also release a version of the altered map that will link seamlessly to his maps.

Office? – This new addition is born out of the necessity for a new method of switching track. In the original Half-Life the player could switch the tram’s path by shooting at switches. While this works great from a gameplay standpoint, it makes absolutely no sense and would not hold up in Black Mesa’s world. This office is also used to justify traveling down through the loop (because otherwise it would be a pointless addition and then what would the purpose of making the mod be?).


I love this idea. Tracking.

And are you gonna include this area too?


That largely depends on if there is enough room for it. The current design might not have room for it, though if I moved the lower right entrance somewhere else (say the bottom of the loop, even though that means fiddling with dev track), I could do some simple wizardry to make good room for it. If I need more that 1300 hammer units then I could just move the loop upwards.

It’s definitely something I would be interested in doing and I am sure I will look into it.


Okay. Then good luck buddy :smiley:


I think the mapping is going really good right now. I started on that room last night and I’ve got most of it fleshed out already.

That being said I had to move the box track down to the bottom of the loop (which coincidentally forced me to do some magic and shift some dev stuff - a doorway - to the left). All things considering though, putting it right there is a little more faithful to the original’s chronology, so I can live with it.


don’t we already got OaR uncut?


I would say no. OaR Uncut focuses on b1, b2, c, e, f, and g. This one focuses on a. These two mods are not one-and-the-same.

Of course, this should have been apparent if you knew what I am doing. Do you know what I am doing?


Possible to combine yours with his version?


Of course! :smiley:

That too is something I said in the very first post~ There will be a version of this map that will transition into TEXTFamGuy’s maps.

EDIT: Unless you mean actually making both projects into one package. I wouldn’t count on it too much, though I would certainly be open to it if approached about it.


I know what you are doing now
There’s no need to be a smart ass, considering you probably will want people reporting feedback, like Text’s threads


There isn’t any redundancy here, is there? IE, there’s nothing you’re remaking that Text is already remaking in spirit, right?


I am very aware of that, and I apologize if I came off as that. I value opinions.

But you have to understand: from my point of view you had assumed that this was exactly like OaR Uncut. I am perfectly fine if you aren’t sure as to what I am doing. I am fine if you want to ask me, “I didn’t get this, can you elaborate on your project?” What I don’t like is when someone comes along, doesn’t understand the material, and then makes up for themselves what it actually is.

Because it makes it seem like you didn’t read the first post. I’m not going to accuse you of skimming it here, but from my point of view that was what you looked like you did.

But anyways, let’s put it behind us. As you said, you’re on the same page now, so I suspect this misunderstanding won’t happen again~

I suppose I’ll answer the biggest question here. How exactly does this mod compare to TEXT’s?

To really look at this, we have to look at his very first map. In that, he recreated what was essentially the crane puzzle, and the HECU fight under the rocket. It had some shades of looped gameplay but it wasn’t integral (and you could argue that too was part of the crane puzzle).

This mod on the other hand recreates the sidetrack with the boxes and the pipebridge room, plus a couple small scenes from the original Half-Life. There is much more emphasis on the loop aspect of the track layout with this mod in that you have to travel one entirely before proceeding.

I actually do see an opportunity where TEXT could easily implement the elevator room in his A1 map (which is something I will mention in his own thread right after this is posted). Since this mod will hopefully compliment what he is making, I’m going to wait and see what he does with it before building that area.

So really, no. No overlap between the two mods. I hope that answered your question :slight_smile:


Alright. :slight_smile: I just wanted to know if there would be anything nonsensical if I installed both mods, and it looks like there won’t be. TBH, I actually wanted something like this in the first place, it always looked like there was supposed to be a loop here to me. :slight_smile: Now, I have two more questions:

Is use of the loop necessary - that is, must you travel to the new areas to get through the map?

Is the loop activated by default - ie, if you just run your tram through without switching anything, will it get caught in the loop, or will it continue past it?


Yes indeed. The loop will be activated by default and the only way to get out if by visiting the security station in the top right corner. Traveling there via tram will take you past some houndeyes (led to rocket and elevator rooms in original) and the pipe bridge room. It… sorta follows the originals continuity, which is pretty good considering my limited options!


Alright! :slight_smile:


I truly am liking you’re idea. At first I was like “what is this guy trying?” but then after reading you’re idea and seeing your pics I am looking very forward to your loop.

Just a question: will you use TEXT’s manner of switching rails for consistency? You know, the blue console panel he uses in his A1 map and the sound that plays upon switching?


Yes and no. One of the luxuries TEXT had with his map is that you were able to look directly at the switch you were operating right from the control booth, so it didn’t take too much to call attention to it. Here though we are in the complete opposite corner from where we are doing stuff, so I have to somehow let the player know that they have done something to the opposite corner.

What I am thinking of doing right now is having a panel with a few switches on it, and then there will be a map of the area. When the player pulls the switch, the map makes a sound and subsequently change.

It might not be possible for me to be consistent at all (though I sure as hell will try). It might not be too big of a problem though because the track switches are in two different settings. One (TEXT’s) is used by a crane operator in a large space but in a single room, while mine is used in a small space but many times over in different locations.

I am being consistent with the switch displays though, opting to steal… borrow the led lights that TEXT used in his maps. I’m sure he won’t mind.

In other news, I’m probably done working for the night. I’ve had a step forward but I’ve also had three steps back.

Bad news first:

  • found out that the SDK has a warped perception on how map leaks should be handled. First of all the file that points me to where leaks are (called a point file), while it loads, does not refresh unless I compile the map. This means I have to fix a leak, compile, fix another leak, compile, fix yet another leak, compile again… It’s horribly inefficient and I am sure it will end up costing me some time. Second off is that even if there is a leak, the complier continues on through the entire process of running bsp vis and rrad, which even at the lowest settings takes a couple minutes. I have turned off vis and rad because bsp tells me if there are leaks (and believe me, the entire map is fucked up if there is even a single leak). Neither of these problems happened when I mapped for Portal 2, so this is something I’m going to have to get used to…

  • Through a program crash and some nonsense about me trying to allocate stuff into new files to ease creation, I lost the top right corner of the map tonight. This section lost was to be the security office where the player switches the track. Thankfully, this only means a couple hours of work, as I hadn’t started on the section yet and I actually think I could replace it/improve on its original design with one hour’s work. Some lost, some found, I guess.

  • Lastly I’ve encountered a scenario where the tools/black textures are not only being visible within the map, but are acting solid. I’m not sure what is causing this (or where it’s coming from). Thankfully I can try using cordons to locate this problem and hopefully eliminate it. This will definitely the thing that I tackle first tomorrow.

The good news is though that one of the simple sections (the split path to the boxes) is completely inside the map. I was actually worried about this because right now I have the track at a 45 degree angle. While alot of people would argue that it’s simplicity is nothing to gawk at, any mapper will tell you that anything that is off-grid is hellish when it comes to fixing leaks and sewing things together. I was afraid that everything was going to be so misaligned that I would have to majorly work on the area. Thankfully the tally was three objects being func_details (which allow for those map leaks I spoke of), and only one of as an actual missing barrier. I’ll be able to post a screenshot tomorrow so you guys can see what this little path looks like.


Arg, with the realism. I miss the old target practice rail switches. :frowning:

You know you can disable VVIS and VRAD and compile and it will create a new pointfile, right? Compile only with VBSP and you can reload the new, updated pointfile. You still have to recompile each time to fix your leaks, but the compiles should take less than a few second. It’ll save you so much time.

I’ll be watching your progress. Probably quietly, but watching nonetheless. I’d add another track or two in that huge empty square. Maybe some rooms or storage or supplies for the players to fight enemies/re-up on some supplies.


I also miss the target switches. Again, great gameplay mechanics but that’s so last decade ago :frowning:

EDIT: Alright I lied. Haha. I don’t think the tools/black textures are even supposed to be there. So that’s one important mystery solved.


Compile with BSP and fast VIS only. RAD turned off. It takes about 10 seconds to generate a pointfile even on the biggest maps. Do this before any time you ACTUALLY want to compile a map and it will save you a lot of time in the long run. If I do a lot of geometry work or anything major in general, where making leaks is a possibility, I always do that first. Sounds inefficient but it saves a tonne of time because when there is a leak you don’t have to wait 5 - 10 minutes for the map to compile and then find out.

The easiest way to solve leaks (which you probably already know) it to untick ALL of the automatic visgroups, so everything on your map disappears. Then tick “World Geometry”. Then untick “Tool Textures”. This leaves ONLY the basic world geometry available in the editor. It’s then substantially easier to see the origin of leaks. Very often you’ll find it’s because you used a func_detail to seal the world and then forgot about the gap behind it, at least that’s the case with me. The other advantage of this method is that you can see stuff you haven’t func_detailed which you originally meant to, and believe me - it’s often A LOT.

If you’re having trouble finding the cause of a leak - I had a lot of problems with the 45 degree tracks causing leaks on my A1 map. It’s because their origins are at the bottom right hand corner of the bounding box. This means that almost any configuration you can put them in will place the origin outside the map - generating a leak. I couldn’t figure out what was causing it either, because the leak was STARTING outside the map and FINISHING there too. My eventual solution was extremely hackish - I simply enclosed the origin in a 32X32X32 block of nodraw.

This is supposed to happen. They’re always solid and visible. That’s their default behaviour.

If you do this, please at least give me a small credit. Those were a surprising amount of work.

Good luck.