[GUIDE] Let's talk about Mann vs Machine.

Discussion in 'Tutorials & Resources' started by tyler, Nov 11, 2012.

  1. tyler

    aa tyler snail prince, master of a ruined tower

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    Hi guys! Let's talk about Mann vs Machine. Specifically, the maps themselves, because analyzing the waves seems hard and not that useful.

    First let's look at some overviews.

    [​IMG]
    Coaltown

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    Decoy

    [​IMG]
    Mannworks

    There are a few common design concepts in these images. Can you tell what they are? There are also some pretty key differences as well, though.

    The main thing these maps have in common is that they are a straight line. They are dead simple. There is nothing to them. They are short and they are basically boxes. The other thing they all have is something I've been thinking of as "the spine": they all have a raised area in the center of the map, drawing players to a high ground that is always useful. The "arms" of the map, the outer high ground, are often less used, if used at all. (The exception to this might be Mannworks, where the spine is cut in half and the arms are more viable hold points.)

    Here are some images of how bots move around the map. Notice that they always bend around the spine.

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    What does this do? It makes each map have the same, basic framework. The geometry changes, but the way you play the maps does not. This means the player is comfortable defending against the robots immediately, because of the similarity and simplicity of each MVM map. Though Mannworks has a broken spine, and Decoy has a short one, they all deliver the same experience: get on the high ground in the middle for the best way to kill robots below you, no matter what path they take.

    All 3 maps also include some way to push bots back or delay them. On Coaltown, there are 2 deathpits. On Mannworks there is a shallow trench, and on Decoy, a large trench. The spine and the ability to push bots back are things that I see as features your map has to have--it doesn't matter how else you do it, but these are core.

    The other thing the maps all share in common? This last thing you can't really tell from above. It's a total lack of detail, even in the 3D skybox.

    [​IMG]
    [​IMG]
    Check out these sweet 3D skyboxes!

    Now I want to talk about each map in specific detail.

    We'll start with Decoy because I think it's the simplest.

    Like I said, it has a short spine. But it's powerful.

    [​IMG]
    The large pickups really help sell this spot despite the lack of viable cover and size

    This building, with the large health and large ammo, can have a sentry on top that sees almost the entire map. The way Decoy is laid out, bots basically funnel through a straight corridor before being split by the spine, then they cross a bridge. A well placed (or quickly moved) sentry can see almost the whole map with the Wrangler. But that range comes with a price: exposure.

    Many engineers opt to build to the side, instead. Decoy also features largely exposed side routes.

    [​IMG]
    [​IMG]

    Crafty engineers may build in these areas, or on the platform just to the right of the second image which I forgot to take a screenshot of. This gives them increased safety, but they have to prepare for the waves coming better. They may also find themselves moving around a lot on higher difficulties.

    Decoy also employs a large trench right before the bomb hole to help deter bots and funnel them into a tight space.

    [​IMG]

    Decoy is the shortest map, so it's important to have something like this to delay bots and also waste their time. It takes a long time to get back up to ground level. Even players are likely to get frustrated should they fall down, and they can jump, unlike the bots.

    The outer routes the robots rarely take are also important, though. As near as I can tell--and I may be wrong here, please correct me if so--failing a wave will increase the chance that bots take the outside paths to the bomb hole. This does two things: Puts them against a wall, so it's easier for them to absorb splash damage, and makes the focus shift to 1/4 of the map, rather than the entire center.

    One thing I think is really important is the start of Decoy.

    [​IMG]

    I really do not like the start of Decoy when I am playing Scout, Pyro, or Spy. In MVM, all three of those classes need a lot of breathing room, especially when all the bots are clumped in the starting area. The way this area is set up, there's only a small closet and an irritating jump route to hide in/escape with. It's pretty unideal compared to Mannworks and even Coaltown, which I'll cover later.

    I'll also note that Decoy, as with the other maps, has two spawn doors facing each other. Why? I don't know! Probably so that Valve could heavily detail a couple areas as normal without impacting FPS? Because it's neat? Because symmetry is nice? I'm not sure!

    Snipers are always hinted to open, easily seen spots. They don't get hinted to windows.

    [​IMG]
    [​IMG]
    Multiple hint nodes in a single area will make a Sniper have a chance to move between shots or take a new position after being attacked

    Keep your snipers in open locations. Coaltown also does this, as does Mannworks.

    Now let's move on to Coaltown.

    [​IMG]

    Coaltown's spine is pretty significant and covers a lot of the map. It is a longer map though. One thing that should be taken note of is that the pickups are more spread apart here, though not very significantly. But it does mean that an engineer needs to take 1 or 2 seconds longer to refill his health and ammo, and those are 1 or 2 seconds that will lose you the game.

    [​IMG]
    [​IMG]

    Coaltown is the only map to feature death pits. Both pits are relatively small and can be hard to use. Contrary to what some people think, killing bots with them gives you their money without you having to collect it--you don't lose the money.

    Coaltown puts extra emphasis on the upper ground beside the main routes.

    [​IMG]

    The side routes are more likely to see use, as they are lower (less time spent climbing stairs) and have pickups very near to the main routes. The side areas near where the bots drop down are similarly more useful than Decoy's, as you aren't completely cut off from your team (visually) if you make use of them.

    Coaltown is also a great example of using func_nav_avoid to stop bots from going to certain areas.

    [​IMG]
    [​IMG]
    Bots really don't want to travel these areas

    It's important that in addition to editing the nav mesh for your bots, you tell them places they don't want to go. This will go a long way toward focusing combat and increasing the "tower defense" feeling on your map.

    Coaltown's bomb hole is interesting, because it dips into a lower area for both bots and players, similar to CP2 on Gorge.

    [​IMG]
    Decoy has the spawn slightly above the bomb hole, Mannworks has it on the same level, and Coaltown puts it down deep

    This makes building near the spawn more attractive, as it's easier to watch bots come at you, and then they're below you, so they are easy to spam. The final area on Coaltown is probably the most interesting for this reason; doing the most damage means getting down in the pit with the bots and giving them the height advantage, which is dangerous.

    Now, let's return to the start of the map.

    [​IMG]

    Coaltown improves on Decoy here. There's more space between the buildings, and in addition, there is some actual useful cover to get behind. Support classes are far, far more useful at the start of waves because of this. When areas of a map aren't a death funnel, players are happy.

    Last but not least, let's go over Mannworks.

    Mannworks is the most complex MVM map because it has two spines.

    [​IMG]
    [​IMG]

    The two spines here basically mean the bots weave around one more time, giving them more places to be missed by players and meaning engineers need to cover more ground. Most of the middle ground is a shallow trench, by far the most useless of the setback areas on each of the maps.

    The forward spine is a great hold because it contains a lot of health and a large ammo, but retrieving the pickups means breaking line of sight to your buildings and the enemies, making them slightly less tantalizing. The second spine is all but useless; engineers are better off building on one of the side routes near the bomb hole because of the proximity to pickups and because if you do build on it, you're turning your back on enemies pushing in. But if you can handle that, it becomes a very powerful spot, as it's the closest high ground to the bomb hole.

    The side routes on Mannworks are largely useless--the ones in front, adjacent to the first spine, are decent for engineer camps, but as anything else they don't deliver.

    [​IMG]

    The start of Mannworks is very open, which is great for support classes. On the other hand, this means bots aren't really funneled down any one path immediately, and classes that rely on splash damage or penetrating multiple targets have a harder time taking down multiple bots.

    Now, let's talk about how the maps are built.

    MVM maps are boxes.

    [​IMG]
    They pretty much all look like this

    The scary thing is, they are also barely optimized.

    [​IMG]
    One HINT brush, areaportals, and that's all

    The thing to keep in mind, though, is that almost all the geometry in them is absolutely vital to cutting visleafs and aiding to cull geometry.

    But that isn't to say that does a lot. The maps are still poorly optimized. Valve handles this in kind of an odd way: underdetailing. Remember those 3D skyboxes? That kind of aesthetic applies to basically everything, actually.

    [​IMG]

    This is an example of the most detailed something will ever get. There's just too many projectiles and moving bots on screen for things to get more complex than this. You won't really see the rich scenes of Mountain Lab depicted in Mannworks, or the intricate trim from Badlands on Decoy. It's just not there.

    Look back at the images I've shown you--the detail level seen on other maps just isn't there. There's not even any sign of life in other areas of the map: no side rooms for detail, no evidence of life outside the map, nothing. In fact, there's only one spot I've seen on any of the maps that use detail sprites.

    [​IMG]
    One blend texture, barely used

    Closing notes

    The basic thing to take away from this?
    • MVM maps are simple
    • They have a raised center area and raised edges, and bots always take the low ground
    • There is always a way to reset or delay the bomb
    • Pickups are often large
    • The maps are barely detailed to preserve framerate
    • The maps are short
    If you remember these things, I imagine you can build a "safe" MVM map. However, the fun in making maps for TF2 lies in taking the normal concepts behind a game type and changing them. With that in mind, I hope everyone that reads this can take these ideas to mind, internalize them, and create something new and fresh with them.

    Good luck, and let me know if I should expand on anything!
     
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    Last edited: Oct 28, 2015
  2. grazr

    aa grazr Old Man Mutant Ninja Turtle

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    Reckon you could speculate on why the game mode doesn't utilise occluders, i would have imagined mannworks particularly could have benefitted from occluders because players tend to hug the back of those buildings to avoid the immense amount of flak from spawning waves. Additionally occluders block player models so if you have 30 scouts on the other side of a structure an occluder would be incredibly effective (though i have noticed occluders don't block weapon models from rendering behind them).

    I guess it makes sense that if you don't detail then you don't need to use what otherwise might be expensive optimisation techniques.
     
  3. Pocket

    aa Pocket func_croc

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    I think the main reason for the two spawn doors facing each other is that it's the easiest way to prevent bots from firing directly into the spawn buildings. Similar to why two out of three exits in Badwater Basin face sideways.
     
  4. tyler

    aa tyler snail prince, master of a ruined tower

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    Yeah, I imagine occluders were tried and just don't help a lot. Plus in some cases you don't want things occluded, like the Tank, which emits a huge plume of smoke as it chugs though. Occluding that particle means you can't locate it as quickly from across the map.
     
  5. Faux Rhinoceros

    aa Faux Rhinoceros Also known as Dr. Element

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    Nicely written. I had a vague idea about the spine concept, but you nailed it.
     
  6. GPuzzle

    GPuzzle L9: Fashionable Member

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    Yyler surprises us again with one tutorial that catered me and is now one of my favorites.
     
  7. henke37

    aa henke37

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    Think you could do a part two that discusses the use of alternative bot routes in more detail as well as exploring the role of the tank?
     
  8. grazr

    aa grazr Old Man Mutant Ninja Turtle

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    I'm not sure occluders are actually that aggresive. They don't seem to have an issue not-blocking CTF or payload outlines and presumably this is the same for the tank, but notably i'm not aware that occluding the source of a particle effect occludes the child sprites that might move into view.

    I guess this is something that should be tested to be sure. Largely it just seems like Valve have been lazy with these maps.
     
  9. EArkham

    aa EArkham Necromancer

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    Here's another I've noticed while working on my MVM contest entry -- the robot carrier is ALWAYS visible from the moment you step out of spawn. It's a small detail, but it accomplishes two things very simply -- it lets you know exactly what game mode this is, and it lets you know which direction you need to go to meet the robot swarm.
     
  10. Tumbolisu

    aa Tumbolisu  I ⌄ I 

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    Make screenshots bigger pls, my internet can still load them and the forum isnt broken enough.
    [​IMG]
     
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  11. Woozlez

    Woozlez L3: Member

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    Tumbo, you know yyler is gone. Why would you necro a thread to say something so useless to the purpose of the thread?

    Anyway, I thoroughly enjoyed reading all that yyler wrote here, and I may even create an explanatory thread of how MVM Underground follows the theme of spines and how it adds the completely new element of flanking.
     
  12. takabuschik

    aa takabuschik

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    This needs an update to talk about bigrock, rottenburg, and mannhattan as well. I'll be happy to post something about them, but I don't know if this is the proper place to do it, since this is Yyler's tutorial.
     
  13. henke37

    aa henke37

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    Just make a new topic. This way more people will get to see it.
     
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  14. worMatty

    aa worMatty Repacking Evangelist

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    Necro tack-on.

    I thought having spawn doors at angles from the player's view allows the map author to use an area portal window and func_brush over the door, without having to worry about the player seeing it when the area portal fades out. On some MvM maps you can just see the brush appear when you walk far away from it but can still see a bit of the door.
     
  15. UKCS-Alias

    aa UKCS-Alias Mann vs Machine... or... Mapper vs Meta?

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    Its actualy to prevent being spawnkilled too easily. If you notice its either 2 oposing doors, or 2 seperate areas you leave at (rottenburg).

    This is because once the final pit is becoming massively attacked some bots will also take the door area. If there was just 1 door that instantly would give frustration since you wouldnt even be capable of distracting them so the others can still leave at the other door. With a 2nd door you get a 2nd chance. Failing that chance is a guaranteed loss. And that 2nd chance might not mean that you instantly leave. But if you manage to get someone into the canyon in decoy for example you delayed the next attack and allows you to focus onto leaving again.

    The areaportals on those doors are just to make the areaportalwindow at the window work properly. Doors are ideal spots for that since they most of the time would be closed.
     
  16. Crash

    aa Crash func_nerd

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    Bump for a good relevant guide.
     
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  17. SmallBiscuit

    SmallBiscuit L7: Fancy Member

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    Just read through this, and I have to say: It's a good read and is relevant to both the contest, and a bit about how valve does things... It was very intriguing, and I am very happy to put some of these concepts to the tests in the contest... (the spine idea was really interesting, and makes a lot of sense...)
     
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