Setting up basic SF2 maps
So you want to make your own SF2 map for your own purposes? Well this tutorial has got you covered, and thankfully its a lot easier to set up than lets say a Payload map. I recommend you set up your own private server so you can very easily test it whenever you need it.
Now this tutorial is not for beginner mappers, this tutorial assumes you have a decent experience at mapping in the Hammer Editor. If for some reason you are a beginner mapper, below are links to some guides you can read up on as well as getting the bare basics down in a video tutorial.
Team Fortress 2 Mapper's Reference
UEAKCrash's Map Making Tutorial list
Now in terms of choosing what to make first, might as well explain what is required for a basic Slender Fortress map.
The Waiting Room
This is an area BLU players will generally spawn in to sit and wait for their turn to play on RED side. Generally every map you see has at least one PvP arena, failing to create one can result in players getting easily bored of waiting and have to watch RED players all day. Mini games and parkour areas are optional but can spice up the waiting time, and how you make them is completely up to you. Note that if you do make parkour areas, keep them at a reasonable length, don't go for Broken V2's short length and don't go for SJG Arena's extra long length unless checkpoints are present. The way the Waiting Room is designed is completely up to you, go crazy if you want to.
The Play Area
This is where RED players spawn in and do the general objective of the gamemode and is needed as much as a working Waiting Room. The size of the RED area can depend on what kind of map you're going for, so if you're going for a survival map its generally small, the smallest you can think of is Boxing Ring, this only works for the Boxing gamemode and should never be used in any other kind of gamemode. Randomly generated environments should never be took into consideration, teleportation areas can lead to issues to bosses down the road, leave them off unless you're doing a Silent Hill approach where everyone teleports to a run area and escape. It is never a good idea to do extra long RED areas as doing so can either lead to frustrating long gameplay or risk of reaching the brush limit.
The choice of making which area first is completely up to you. Personally, I get a basic waiting room down with nothing in it but at least spawn points and then work off of a RED area, just so I can get an idea of what I want to make for RED side, and whenever I'm done with the layout of the RED area, I switch over to the BLU area. The choice is up to you which area you want to make first and how you should manage them.
Now you really don't have many limitations when making a Slender Fortress Modified map, especially in the BLU area, but it boils down to many requirements whenever making the RED area despite the growing smarter AI.
Geometry
Most maps have flat terrain for good reason, this allows bosses to easily travel through the flat terrain and catch up to RED players easily, occasional slopes for downstairs or upstairs areas are ok to do, but if you're going for the stair look instead of a simple slope, make sure a clip brush is over the stairs to avoid rapid boss jumping. Displacement areas are generally accepted if done right, but I recommend getting at least a base flat terrain done if you're going for the outdoors natural feel. Its always a good idea to watch for spots the AI can't simply reach easily, for example you could have 2 platforms and slopes leading up to them, if you're gonna do this kind of thing, make sure you have NPC clips so that the bosses can easily catch up to RED exploiters. We'll get into deeper detail on how to make bosses traverse heights players can't.
Death pits and traversing
Generally death pits are commonly found over heights that players might get knocked off by the boss or even trying to traverse them using jumping. If you're going for this kind of style, make sure a NPC clip covers the pit so only the boss can walk over it and not the players. The jump during the escape phase on Cliffroad doesn't have some sort of NPC clip to help bosses go over it, so avoid this kind of easy mistake.
Doors and brush appearing
Sometimes we want doors in our map that are brushes rather than a single mesh that bosses can see right through. If you're gonna make a door that can be opened by the player, make sure the boss can open the door as well otherwise there is no way a boss can get unstuck out of the door. Also if your door can only be opened by a specific event, you have to use an entity called tf_point_nav_interface and make the event call RecomputeBlockers, we'll get into how to use that properly later.
Clip brushes
Technically you won't need this for flat terrain or sloped areas, but you will need this for restricting players to get up certain heights. You don't want your player to go out of map bounds where the boss can't reach you. Allowing players to get up heights bosses can't will result in server breakdowns and cause intense lag from even a single boss, even with the blocked area fix back in 1.5.3.6. Most of the time a clip brush should be placed to avoid boss exploitation where the boss can either not follow you and take a extra long path to reach to you or where the boss needs to reach you but can't in any other way, so its a good idea to think about what places players shouldn't get up to. Like I mentioned before, its crucial to smooth out stairs with a clip brush to both avoid rapid boss jumping but also that jittery effect when players move up stairs. Surfaces smaller than 32 hammer units wide should always have a clip brush, most commonly you'll find these surfaces on hand rails so either make them non-solid meshes or place a clip brush over them.
Dynamic events
Dynamic events that do not effect the map's geometry is always fine, so dynamic lights are allowed. But having events that move the geometry of a map that isn't considered a opening and closing door is considered a bad idea, especially randomly generated environments. Take for example SCP-087-B, that map doesn't let bosses move easily due to the traps present in the map that are randomly generated. If you're going to make a map that you have to press something to disarm the trap that leads to a pitfall or something players need to pass by, NPC clips are the way to go, never make those kinds of events unless you really need to.
Health placements (And ammo for RAID)
If you're gonna make a Boxing, RAID, or Proxy Survival map, health placements are a good idea. If its considered a Boxing map, health kits must respawn, under no circumstances must they not respawn, this can lead to impossible gameplay where the RED players just can't beat the champions. Proxy Survival maps are a mix of both, you can have some respawnable health packs and some that do not, for instance, you can have small health kits respawn but have them scattered around the map, and make medium and full health kits not spawn, or restrict them to a longer timer like Boxing Ring does with the full health kits. RAID maps depend on how many will be placed, if so many health kits are placed, none should respawn, if very little are placed, some should respawn, the same applies to ammo packs.
Lighting
This is where the choice is up to you on this one, you can have a fully bright map like Boxing Ring, or a generally dark map like Underground. Alternatively, you can have all RED lights turn off when all pages are collected, but this requires a lot more time to work with. Its critical to make the BLU area bright enough for everyone to see, pitch black BLU areas or near pitch black BLU areas are never a good idea unless you're doing some sort of dark path that leads to a new area.
Ok, so theres been a lot of confusion with using slender_ and sf2_, but both titles actually work according to the source code of SF2 Modified. For maximum chances to be a SF2 Modified map, go for sf2_, regardless, use slender_. Now naming the map can be annoying to some, none of us want conflicting map names using names like slender_city or slender_ghost_town. Doing so can result in conflicts with two maps, 2Fort was a SF2 map first made by Demon Hamster, but when this was consideration, the Proxy Survival map had to be Two Fort. So think about making an original name almost no one can think of if you need to.
Generally there are no rules on how to update a SF2 map as the choice is up to you, but to make your life easier, here are a couple of tips for updating a map.
New geometry
This one is fine to do as some people want new areas in a map, if you're gonna go for this, you do have to build that part of the navmesh, thankfully you can use nav_generate_incremental with the empty areas marked as walkable, this saves you lots of time from building a new navmesh.
Moved geometry
In this instance, you actually have to rebuild the entire navmesh. Its always a good idea to get the final version of a map out first and then build the navmesh when you know for sure the map is gonna stay like this, unless of course you open up new areas or make small changes like add props. This also applies to editing geometry. Once again, if you desperately have to move existing geometry, you generally have to rebake the navmesh, so the way you use time is up to you.
Ok, so you can use some sort of external program like VIDE to pack up all of the custom content, never pack a navmesh into the map, as if you need to make some changes, you simply can't as the packed navmesh will always be selected. Trenches falls into this category, so please, don't make this mistake. As for other content like TXT files, texture files, model files, and sound files, those you can easily pack. If you want to pack custom content and you don't know how to, the link to use VIDE is below.
Now when it comes to HDR and cubemaps, this is fine, however you should always build your map and cubemaps in both HDR and LDR, this can be achieved by compiling your map with a Normal compile and turning on the HDR option. When you get to the cubemap baking, you want to build them in both HDR and LDR, otherwise issues can be caused down the road. Its theorized that people can crash with HDR only builds, so take HDR and LDR into consideration. Below is a link on how to build cubemaps for HDR and LDR, I recommend you start your baking with mat_hdr_level set to 2. Its ok if you don't want your map to have the HDR option, just make sure you build the cubemaps the same way.
Now that you know the basic rules of making a SF2 map, the question is this, "What kind of map should I make for SF2 Modified? What are my options?". Thankfully you have a decent amount of options.
This is the most basic idea of a map, collect all the pages and get to the exit. Usually they are maze like and are generally fairly large maps, but not as big as lets say Silent Hill. Now the exit doesn't have to be a simple trigger you have to touch, you could also put down a small run sequence, the choice of how you make these maps is up to you.
The second most basic idea of a map, survive for X amount of time then get to the exit. These maps are smaller than page maps and are considered the second smallest maps to exist in SF2. Players usually have to either hide or circle around a map to avoid the bosses and get to the exit once X time is counted. Alpha Complex does 40 seconds, Decay does 35 seconds, and most maps do 30 seconds. Of course these maps have long chasing bosses like Dr. Trager, Chris Walker, Hans Volter, etc.
This concept is somewhere in the middle, players get an objective or two, and then run to the very end of the map to escape. Before players would have to play around what strategy they have to play in order to avoid bosses that are in front of them. In recent years, the entity sf2_bosseschaseendlessly now exists, and you can actually make players have infinite sprint and have a quick boss chase you down from RED spawn to try and kill the RED players. In the end, the choice is up to you.
The most complex concept, players would collect set number of collectibles and travel to the next designated area, on the way they would do set number of objectives. The only maps that use this concept is Swarm and Mountain Complex. We'll get into how to do Mountain Complex like maps. The way these maps function is up to you.
In these maps, you have to kill either a super strong boss or set number of bosses in order to either progress or win the round. The only maps to exist are The Tower and The Citadel, each having their own unique concept. This kind of map should be taken with a grain of salt, as at the moment SF2 Modified doesn't support the boss features like Boxing Ring does.
These maps don't exist in SF2 Modified, but you can make some in the upcoming Proxy Infestation Update. In these maps, players are set to survive just like in Survival maps, however the proxy master boss knows where you are at all times and they spawn in proxies to help kill the RED players. These maps are scattered with health packs for a balance between proxies and RED players. The current proxy maps are Two Fort, Biotics Lab, Mombasa, and Shadow Raid. If you're gonna use these maps, use an info_target named sf2_isproxymap so in the upcoming 1.5.4 update, the base should be ready.
These maps are similar to RAID, but the difference is you have to kill the main champion with your melee weapons and utility weapons like the lunchbox items, the banners, and the rechargeable throwable items. These are the smallest maps, consisting of the RED and BLU area being combined into 1 giant arena for RED players to fight and BLU players to watch the fight up close. Health kits are not as scarce as lets say Proxy Survival maps, and full health kits are usually ran on timers. The only map that uses this concept is Boxing Ring.
Arena is an upcoming map type that allows the plugin to spawn set bosses per wave or add conditions to the bosses per wave. Because its a work in progress, no maps use this logic, the closest you can get is Zen Arena and SJG Arena, where as the upcoming map for this gamemode is Renevant.
To find all of these entities, check out the wiki page on list of map entities, a download for all of SF2 Modified's entities and gamemode functions where you can look at them in Hammer should come in the future.
If your map is fully working and you think its ready to go for players, you can always submit them to other SF2 Modified servers if you want to, or if you want to submit them for official updates, you can always get in touch with me on Steam or Discord (If you can find me there that is). In the future I'll make a category on how to set up each map.