I haven’t been all that impressed with some
of the maps that Valve’s accepted into TF2. But there is one that caught me by surprise
when it was added. And that map is Helltrain, a community-made
Halloween map that was added to the game in 2022. Your typical Halloween map comes with things
like the underworld, pumpkin bombs, and spells, which gives them their own unique aspect that
we don’t see in regular or smissmass maps. And no, let’s not talk about Breadspace. While Helltrain does have all of these things,
it has so much more that gives it its own special distinction across all maps in the
game. And in this video, I want to explain why and
walk you guys through some of the technical aspects of this map to gain a better understanding
and appreciation for how it was created. So let’s begin… The first thing I want to talk about, which
is perhaps the most obvious, is the train. In-game, it looks like it’s chugging along
the track through a variety of wild environments. But, in reality, it isn’t. In fact, the map doesn’t actually move. It’s everything around it that does. Just like how the Earth is the center of the
universe and everything orbits around us. In this case, it’s the props and skybox,
or skyboxes, that do. These giant wheels on both sides of the train,
as well as the smaller ones up at the front, aid in the illusion that the train is moving
because they’re both dynamic props with built-in animations. And if we load up these models in Half-Life
Model Viewer, we can see exactly which parts of the models are moving. These animations are activated by this SetAnimation
input– which runs whenever the map loads up or a new round begins– and their speeds
are controlled by this SetPlaybackRate input, which you can see, is triggered by a number
of different events. These different parameters for the PlaybackRate
input are what give the illusion of the train speeding up and slowing down. And speaking of slowing down, the sparks behind
the back wheels are info_particle_systems that are turned on and off upon the execution
of this skybox_coaster_anim6 relay, which is intertwined with a bunch of other logic,
but all you need to know is that it’s connected to the whole process that goes on in the rollercoaster
section, which I’ll explain later in the video. So now that we know how the train gives off
the illusion that it's moving, let’s take a look at the sky, which is without a doubt
the most remarkable aspect of this map. Each time the map loads or a new round begins,
one of the following five skyboxes is randomly selected by this logic_case entity: ocean,
desert, hell, forest, and castle. And each time the train enters this portal
(which spawns at the conclusion of each skybox stage), a new one is picked at random to take
its place. The rollercoaster skybox, which is undoubtedly
the best of the bunch, is enabled when rolled by the wheel of doom, which runs each time
one of the five skyboxes is activated. Now if you know anything about the skybox_swapper
entity, you may think that that’s what’s responsible for the swapping of these skyboxes. But that’s not actually true. You see, the skybox_swapper entity changes
the 2d skybox, which is what you see in most TF2 maps when you look up at the sky. And, while Helltrain does have a 2d skybox,
it never changes, yet we only see it in the desert and forest stages. The rollercoaster stage does look like it
uses it as well, but in Hammer, we see that it’s merely a copy, and I’ll explain why
the mapper did this in a bit. I want to take a moment to talk about the
wheel of doom. Now, this wheel isn’t unique to Helltrain
by any means– after all, it’s been in the game for years and goes by the Wheel of
Fate in Ghost Fort– but on Helltrain, it does have some special rolls. In the wheel_of_doom_pick logic_case entity,
we see all of the possible outcomes in the Outputs menu. The first of interest is what the mapper refers
to as “swords.” The icon associated with it, which we see
in this wheels_diffuse .vtf file, looks like a regular scout with a stretched torso, and
that’s exactly what this ability does. The other ability called “spiral” coincides
with this spiral icon, and that’s the roll that takes you to the rollercoaster section. In case you haven’t figured it out already,
this map takes advantage of 3d skyboxes, which are all bundled together off to the side of
the map. To keep things as simple as possible, 3d skyboxes
are just regular models that are scaled up in size when placed around an entity called
sky_camera. And if we search for it in the entity report
menu, we find that it’s right smack in the middle of all of these skyboxes. It all makes sense if you imagine the train
being right on top of this entity– everything around it is scaled up. Now if we double-click on one of these skyboxes–
for example, this ocean one– we see that it’s enabled by this relay, and double-clicking
it, we see all of the stuff associated with that skybox. For example, this line right here is responsible
for activating the wheel of doom right after a new skybox loads. And, there are a lot more outputs here responsible
for enabling and disabling certain things, but going through each one would be too tedious
for this video, so instead I’m going to jump straight to the inputs tab, which is
where we see the skybox_random entity, which is what I referred to earlier as logic_case,
which is the driving factor behind the random selection of this orchestrated chaos. Alright, so hopefully you understand at least
a little bit about skyboxes and how the map changes, so let me explain how the coolest
part of the map– the rollercoaster section– works. So here I am back at the rollercoaster skybox
with this crazy drop and loop. And I’ve hidden everything so that there
are no obstructions. Since we know that the train can’t move,
there’s only one way for all of the craziness to happen. If I position myself on the track just like
we see in-game, double-click on the skybox, and then the “Model” tab, there are six
actions and a reference. The reference is the starting point, and the
ride sequence starts with Action1. As you can see, we’re starting to go down
the track, and if we select the subsequent actions, we go through the entire ride. And just like I described previously with
the wheels, the speed of these animations is controlled by this SetPlaybackRate input. The illusion is easily broken if we zoom out
and then run one of the animations. In this case, Action3. You can see the skybox rotating around the
origin, which is where the train is. So throughout the entire ride, the skybox
is rotating in perfect sync with the train’s wheels, game audio, and other effects. How cool is that? Another thing I find cool is these two jump
pads in the middle of the map. There’s one that takes you to red’s roof,
and another to blu’s. While I created my own boost pads in a version
of badwater I made called boostwater, these are the only jump pads you’ll find in an
official TF2 map. And unlike boostwater, where I used trigger_push
entities, Helltrain uses what are called “trigger_catapult” entities, which launch players along a set
path once they’ve made contact with this trigger region. It’s a small addition to the map, but it
allows players to reach the roof areas much quicker and I just have a lot of fun using
them. So the last thing I want to go over is this
little minigame area that all players are teleported to in case there’s a draw, which
takes place in the hell skybox. All of these cubes you see mark the locations
of this lava rock platform. And this logic_timer entity sets a random
time interval between 6 and 60 seconds for each platform before it descends into the
lava, killing any leftover survivors if they haven’t already killed each other. It’s a neat little area that you probably
wouldn’t experience in your average game of Helltrain, so props to the mapper for throwing
this in. Everything I’ve described about Helltrain
makes it one of the most innovative maps in the game, and that’s not even taking into
account the things that I didn’t talk about in this video, like the map layout and custom
assets. It’s clear that Helltrain took a long time
to make and that the mappers were extremely dedicated to the project. And for that, I salute them for bringing us
what may perhaps be the most unique map ever in Team Fortress 2. Thank you for watching. This is LED, switching off.
