3 - First Principles - Humans

Human Base Principles
Human bases have a few things in common with alien bases, but mostly the strategy for a human base is entirely different. Similarities include the fact that you must pay attention to how allies can navigate in the base. You must ensure wounded/empty soldiers can come into the base and easily get to the medipad/armoury. Also, you must avoid building structures in a way that makes them open to sniping. Anyways, here's the list of principles that I'll be discussing in this guide

• Provide a bubble of safety from all aliens.
• Facilitate reload/healing for allies
• Make chasing dying aliens easy
• Create a clear platform for attack

Provide a bubble of safety from all aliens.
I have a clear mental picture of what it's like to play as the aliens against an average human team: I imagine a monkey breaking open a nut. The monkey may or may not have a clear path to his goal, but he's trying all kinds of crazy things, and eventually he'll find the crack that will get him in. I bring this up because the first point of a good human base is to be a difficult nut to crack. This means that turrets shouldn't be easily jumpable by goons, turrets shouldn't be left alone to be circle-strafed to death, lines of turrets shouldn't be so far away that aliens can jump over them and ignore them to get to the chewy center, etc. One of the worst moments for humans is when the last turret near their medi pad falls, leaving everyone open to constant dretch nibbling. A well designed base should allow each human defender to handle 2-3 alien attackers with very little base upkeep. A poorly designed one will require 2 human defenders per alien to keep it alive.

Facilitate reload/healing for allies
Humans are the exact opposite of aliens in that they require constant upkeep to maintain their ammmo and health. As such, humans constantly have to return to base to heal up and resupply. A good alien player can often kill a superior human player by watching his ammo and health. Several small attacks will eventually weaken a human - the alien then moves in for the kill as the human returns to base. Your base should make it very easy for returning allies to get behind protection when they are weak. For this reason, defensive measures such as a line of turrets from wall-to-wall are a bad idea. Returning allies may not have the stamina to make the jump over the line, and may end up dead just a few steps from the medipad. Also, in teams where you have 8+ players, consider adding a second medipad. Not only can it speed up the healing of one ally if they are grouped close together, it can rapidly reduce the dangerous wait time an ally has to wait for full health.

Make chasing dying aliens easy
At S3 aliens will be constantly attacking your base to try to crack the nut. At 400 health, it usually takes several seconds of constant fire to kill a tyrant. Most tyrants know this an will time their attacks so that they exhaust most, but not all, of their hit points destroying parts of your base before fleeing to safety. One of the best defenses against this is to chase the tyrant down and kill it while it flees. Choose a base that makes chasing easy. Long, straight hallways are ideal as they allow you to shoot the tyrant with hitscan weapons (like the chaingun) for several precious seconds. Blind corners and doors are a bad idea, as the door offers instant cover, and corners allow another tyrant to hide, waiting for any chasers. Similarly, ledges should be avoided unless they can be covered by an ally with a jetpack. High ground is beneficial, provided it isn't too high, as you can shoot while you fall after an alien. The ideal for humans is large tracts of empty space with no cover.

Create a clear platform for attack
This final point is a subtle one. Victory comes only from attack. Of course, if you build a good base, it will encourage your allies to camp in it because they're safe. So, how do you encourage your allies to leave the base and win? First off, try to build close to the alien base. Aliens get few natural advantages by being in their base compared to humans. Generally there is a booster there, so they get to heal at double the normal rate, and they will more likely have venom when they fight. That's about it though. Humans, on the other hand, can avoid being slowly bled to death on their way to the alien base by being much closer. They are also safer, as they are likely to travel with some teammates if the trip is short. They'll have easy access to more ammo. In fact, very few human teams can be stopped from destroying the alien base before S3 if they have a single small base very close by that provides nothing but a medi, an armoury, and a single turret to kill dretches. There are other ways to create a clear platform of attack. If you choose a base location that makes the path to the alien base obvious, and free of a lot of dangerous side-paths where aliens can ambush you, all the better. Think about the difference between the simple hallway in ATCS and the large open area with the box. Nearly all human attackers prefer the hallway because it provides little cover and few good ambushes. It's impossible to get lost in. The outdoor area, conversely, always gives the aliens somewhere to hide if they get low on health. You're in constant danger of death from an alien jumping down on you from the box. The large, open space makes dodging easy.

This principal mostly has to do with looking at the map at large. Where will my choice of base put me in relationship to the alien base? Major level features? How will it provide a path to the enemy base? How can the aliens use my choice of base against me? Will they be able to easily ambush attackers as they leave the base? For instance, on karith there are essentially 3 paths from default base to default base - the one up the human stairs, the one that goes outside and the one that goes through the hallways and the big room. If you move a base, say the alien, to the elevator room, you have now contracted the level down to two paths - the one through the big room and the one through the outside. The path up the human stairs now becomes only a second way for the humans to get out of their default base. If you move the human base to the elevator room, you have done the same thing, but now the path through the default human base does nothing. We'll explore this more in the detailed analysis of different bases


Basic Facts
Just like with the aliens, there are some basic facts to cover about humans that are not included in the manual that need to be discussed before we can move on.


Let's get started with turrets. Also known as rets. Turrets are extremely important. You need to know everything about turrets, how fast they move, how far they shoot, how much damage they do, how to kill them, how to keep them alive, how to make them happy and how to make sure they aren't covered in little aphids. Here's all the information you need:

522 #define MGTURRET_ANGULARSPEED       8  //degrees/think ~= 200deg/sec
523 #define MGTURRET_ACCURACYTOLERANCE  MGTURRET_ANGULARSPEED / 1.5f //angular difference for turret to fire
524 #define MGTURRET_VERTICALCAP        30  // +/- maximum pitch
525 #define MGTURRET_REPEAT             100
526 #define MGTURRET_K_SCALE            1.0f
527 #define MGTURRET_RANGE              300.0f
528 #define MGTURRET_SPREAD             200
529 #define MGTURRET_DMG                HDM(4)
530 #define MGTURRET_DCC_ANGULARSPEED       10
531 #define MGTURRET_DCC_ACCURACYTOLERANCE  MGTURRET_DCC_ANGULARSPEED / 1.5f
532 #define MGTURRET_GRAB_ANGULARSPEED      3
533 #define MGTURRET_GRAB_ACCURACYTOLERANCE MGTURRET_GRAB_ANGULARSPEED / 1.5f

That's all the code for the game relevant to turrets. Okay, not ALL of it, but enough that you should understand several things. First off, the turret range is exactly the same as an acid tube. How do I know that? Because last page I told you that tubes have a range of 300, hives and trappers 400, and here we see MGTURRET_RANGE = 300.0f, or, exactly the same as an acid tube. We also see something very important that have started many arguments with newbies. MGTURRET_DCC_ANGULARSPEED = 10, MGTURRET_ANGULARSPEED = 8. "What's that mean Ender?" Well my boy, that means that when an MGTURRET has a DCC it increases its angular speed by 2, or a factor of 25%. What is angular speed? The rate at which it turns. Incidentally, the ACCURACY TOLERANCE goes from 8/1.5 = 6 to 10/1.5 = 7.5. That's good. That means DCC's actually help turrets work better. As far as I can tell, they don't shoot faster, they just lock on to targets faster, which is also very useful.

Another thing. Turrets do how much damage? HDM(4), that's right. Or just 4. 4 Hit Points of damage. Per 'think cycle'. What's a think cycle? My goodness, you really need to read more code. The think cycle is how Tremulous handles buildings doing whatever it is they do. They 'think' by running the think method. The turret, being a wonderfully smart device, thinks by checking to see if it has a valid target, then shooting at that target if it has one. The think cycle timeout tends to be around 1/10 a second, so you can expect to take about 40 damage a second around a turret. Eh...that's not totally right, dretches have 25 hp and they die in about a second. But, yeah, you get the idea. (Thanks to ThePyro for correcting my previous error on this section). Also, testing showed that a turret can kill a full (400) tyrant in almost exactly 15 seconds. That means that a turret does 26.67 damage per second.

What else can we glean from these numbers? Well, turrets have a VERTICAL_CAP. What this translates into is that turrets can't point all the way down. They can point all the way up. Imagine a pumpkin that has had the little stem part removed so you can get your hand in it to carve the guts out...then put the turret right in the center of your pumpkin. Then turn it upside-down. That's where a turret can shoot. In other words, a turret can hit an area that is described by a sphere with a cone removed from it where the cone is aligned along the negative y-axis and has an angle of 30 degrees. It looks like this:



Now, this image is not a line showing where the turret can hit you. I realize this might be confusing if you aren't reading my guide but just looking at the pretty pictures. This line shows you the point at which the turret can't hit you. Step within that line (closer to the turret) and you can't be shot by it. Why is this useful? Obviously so you can do things like this:



Yes, this is me, as a dretch, eating a turret without taking any damage. How did I do that? Well, I was smart and I looked at the ret from far away and took note of which way it was facing. Then I ran towards it from the other direction. It was spinning to shoot me when I got into it's "safe zone" - the spot under it where it can't shoot me - and stopped moving. Then I ate it from below. How insidious. This is what most good players will do to your base if you foolishly build turrets on ledges.

Okay, so now that we've covered a turrets safe zone, let's show its kill zone really fast.





So, there it is. You can see that the range is exactly the same as an acid tube, which we would expect because that's what the game code says. Here's another shot of a turret's kill zone



The reason why this image has such a broken circle is because 1) the turret cast's a sort of shadow around the bumps because it can't shoot through walls and 2) the range is being cast on a vertical surface and a ground surface. I wanted to show that the range of a turret is exactly the same in every direction (except straight down, remember). So, if you wallwalk and head for this ret you will find that it will almost always shoot you when you are on that wall. I hope that's clear.

There's just one more thing to cover with turrets that is very important. That is that they must turn and fire at their targets. They will not fire until they are pointing right at the target. How do you use this? Well, let's show you some interesting pics first.

Here is the default ATCS layout's front entrance for the human base. You look at those turrets and you say 'man, those will stop dretches. They'll be dead. No way their getting in here.' Y'know what? You'd be right. But only for dretch #1



To prove my point, here's my first run as a dretch. You'll notice that the dretch is dead and the rets haven't been hurt at all.



I assert though that because the turrets have to turn to hit their next target those turrets can be destroyed by one other dretch.. Maybe you don't believe me, maybe you do. Here was my first try. I tried to kill those rets with one dretch, then switched to humans to show you how it went.



ZOMG!!!! OUR BASEIS TEH DED! Yep, one dretch later you can see a smoking ret and a nearly smoking ret. Now, I said they would be dead, and they aren't - I didn't try very hard. Had I been a more skilled player, they'd be dead ('course, then what would I take a picture of?). How did I do it? Take a look:



First, I ran in where the rets weren't pointing. That seems obvious. By the time I hit the first blue arrow the turret farthest from me stopped turning. Why? Because turrets won't even turn to face a target if they can't shoot it. Turrets can't shoot through other turrets. Therefore, turrets won't track you through another turret. That means, you run in along the first red arrow and likely don't get shot. You then slow down in the blue arrow and do a great deal of damage to the closest turret by slowing down a bit and biting several times. When the nearest turret is close to hitting you you move to the middle, between the turrets (second red arrow). Both turrets should start tracking towards you. Make for the other side of the (as yet) undamaged turret. At this point, turret one will stop tracking you and you get lots of time to nibble on turret two before it spins to hit you. Then repeat until they are dead. It's not that hard, you can fit a dretch between each turret and the wall nearest it. It's even easier if you jump.

Jumping is a useful technique around rets. They still have to track you when you jump, and you can jump high, fast and far. This makes it possible to circle-strafe turrets against walls and kill them too. Look at this one:



So, you circle-strafe around the ret halfway, then jump (the blue arrow) over it (make sure you look down - you can hurt it constantly), then circle strafe some more. Twice around should kill it. Here's another example of how to use this strafing to your advantage...



This is a fairly common base on Arachnid2. It's an easy move and it looks like a good idea. There's a handsome wall of rets, and look, even a dead granger. The problem with this is the ret's turning speed and the fact that you can circle-strafe all of the rets together. "What the heck? You can't! There are pillars!" you say. Ha. See those stairs behind/above this little base? You can circle the whole base. Look at this next shot:



How did this happen? One dragoon did it in about 30 seconds by jumping across the rets. You see, a dragoon can pounce things without hitting them and stopping. It's tricky, but quite doable, because of the way the game is programmed. The dragoon's pounce is like a little dagger that sticks out of a dragoon's nose. If you touch the ground, the dagger disappears. If you touch another object's bounding box, you use the dagger up. The dagger points in whatever direction you are facing. So, if you charge up a pounce, jump, then turn 90 degrees to either side and brush against something it will do the same damage is if you had jumped right into it...but this way you go cruising past. Because these turrets are in such a pretty line, we can cruise past all of them and they will only shoot for the instant that the dragoon's body intersects their line of fire. Take a look:



There's my goon after several pounces. Each time I pounced that line of rets I killed a ret halfway dead. On the other hand, the rets did 20-35 damage to me because they couldn't turn and shoot me fast enough. 20-35 damage is about 4 more seconds worth of healing time than what it takes me to circle around the whole base. That means I can almost constantly pounce this line of rets. Within 60 seconds, they will all be dead.

One caveat to this is that if I pounce wrong and I happen to get snagged on a ret, or I land in the middle of them, I will take 100 dmg per second I stand there. That's dead, unless you're quick. We all take risks for the cause...

Also, in this image I have shown my basic movements. Walk down the stairs (blue), turn, pounce at the red. A full pounce should get you almost all the way past all of the rets. Make sure to turn and to face the ret. You should hear a low clicking type sound whenever the pounce hits something - that means you're doing it right. Practice this at home to learn how a goon works.

Here's some common configurations of rets and how to kill them...


Difficulty: 3
Analysis: This is a common layout for a bare-bones forward base. It provides power, medi, and anti-dretch. It's harder than a lone ret because it has the repeater giving it a bit of cover. Here you must come in where the ret isn't facing, then either jump or wallwalk (I prefer jumping) and continue your circle strafing. It's MUCH easier as a basilisk though.


Difficulty: 5
Analysis: This is a default layout for arachnid2. It is harder than 2 rets for 2 reasons. First, it uses a wall. Second, the turrets are spread just a little bit too far, which makes it harder to move along the red arrows without the farther turret tracking to you and getting some shots off.


Difficulty: 7
Analysis: Another one from arachnid's base layout, these two rets have upped the difficulty more for 2 reasons. 1, there isn't nearly enough space around them to manuever. All it takes is getting caught on one of the 3 corners around these two rets to stop your movement and end your life. Two, the steps behind them can screw up your motion. Steps are dretch-bane because your speed will cause you to go airborne off of steps no matter which way you are running them. Airborne means you can't strafe. So, just as you're circle-strafing those rets, you hit 2 or 3 little split seconds of loosing control of your dretch. Lovely. The best way to kill these rets is with a dragoon. A goon can easily jump over these and do half-damage to a ret while taking almost nothing. 4 Jumps and they die, and you should be able to do that and only take 50 damage, if not less. Practice that.


Difficulty: 2
Analysis: This is a common configuration (minus the base) for arachnid. Rets all over boxes. After all, rants can't climb or jump high, right? Well, think about this. A lone dretch goes along the red arrow and stops at the x, either dying valiantly or waiting just long enough for the rets to face him before running away. He then goes around and comes in at the green line where he uses the ret's tracking time to get into the first green circle. Uh-oh, now none of the rets can shoot him, and he can eat the first two rets. Now he runs to the next green circle. And so on. All the rets are dead, and all he had to do was use their shadow region...


Difficulty: 2
Analysis: You would never use this on arachnid (I hope), though you see it on other maps. 3 Rets in a little curved shape. It's supposed to help with goons. Or something. No matter what, you can jump over these and totally destroy them. As a dretch you can circle-strafe them all together. Treat it like one big ret. You'll eat them all in no time.


Difficulty: 4
Analysis: This is common enough on arachnid. See, now the goons can't jump it (ha, unless you've figured out how to jump across them and hit them, see above). Dretches can't circle it. Rants even have a hard time hitting them. Great, right? Wrong. Use the pillars as cover. Pop in and get 2-3 bites while the turret tracks to you point 1. Then go around the pillar to point 2 and get 2-3 more bites while you get tracked. These rets can't cover each other because of the pillars, and rather than protect them the pillars end up protecting the dretches. I gave it a 4 only because it's unlikely you will be left alone to do this long enough to kill the rets, but you never know...

Teslas
So, now that we've thoroughly covered the basics of turret placement, let's get on into teslas. First things first, of course, some facts about them

#define TESLAGEN_BP                 10
#define TESLAGEN_BT                 15000
#define TESLAGEN_HEALTH             HBHM(220)
#define TESLAGEN_SPLASHDAMAGE       50
#define TESLAGEN_SPLASHRADIUS       100
#define TESLAGEN_REPEAT             250
#define TESLAGEN_K_SCALE            4.0f
#define TESLAGEN_RANGE              250
#define TESLAGEN_DMG                HDM(9)

What does this tell us? Well, Teslas cost 10 BP. That's 2 more than turrets, in case you aren't paying attention. Teslas have 220 health, or 30 more than turrets. Unfortunately, this isn't enough to change a lot. It does change a little. Namely, because goon barbs do 110 damage, 2 barbs will exactly kill a tesla. Sad, but true. So, if a builder heals a tesla even once while it is being sniped, it'll live. Not so with a turret. Second, because tyrant slashes and full-charged dragoon pounces do 100 damage exactly, it takes 3 pounces or slashes to kill a tesla, whereas two will do it for a turret. Good to know. A fully charged tyrant trample will do 110 damage...so that means again, exactly kill a tesla in two charges. Interestingly, since most tryants will charge once, then slash, it's good to know that a charge+slash combo will leave a turret dead, but a tesla with 10 hp left. A tesla has a base damage of 9, which is double that of a turret. Tests show that a tesla can kill a full tyrant (400 hp) in 12.5 seconds. This is only 2.5 seconds faster than a turret and means that teslas do a paltry 32.0 damage per second. Of course, this is improved over turrets because they don't have to aim, so that is constant damage reguardless of whether or not you're dodging. I'll sum this up more later when I get around to analyzing tremulous.h and writing up a guide on that.

Okay, so more practical data on teslas. First, tesla's range is not calculated from the little ball on the top (which I originally thought), but rather from somewhere in the center of the bounding box. The range is actually slightly smaller that that of a turret (250 as compared to 300). Here is the quintessential range shot:



This doesn't really show the relative difference between the turret and the tesla. So, here's another image with that particular difference highlighted. You'll notice the circles are not concentric - that has to do with the fact that they two things aren't occupying the same space. Sorry.



Here's another shot with a slightly different angle on it. This shows how far the tesla can reach downwards from its center, as well as sort of an isometric view on its horizontal reach. I'm hoping these three together give you a clear idea of the range of this thing...



Now, looking at that above image you might be tempted to say "But, Ender, you sexy beast, you're kinda missing parts of the circles around the sides..." To which I would respond "actually, no, because the tesla, contrary to popular believe does not shoot around corners" I have no idea where that particular notion came from, but it ain't true. The tesla is just like the turret it this respect - there must be a direct line from the center of the bounding box of a tesla to its target for it to fire. Let's bold that, shall we? There must be a direct line from the center of the bounding box of a tesla to its target for it to fire. What, don't believe me? Your granny told you that it was so? K, look at this.



You'll notice by my subtle annotations which thing in this shot is dead. It's not me, the dretch, even though I had to bust out my little tiny dretch camera to get this shot. See, no direct line of sight between our bounding boxes. However, I can nibble on the corner of the tesla's bounding box and kill it. And yes, apparently dretches can hurt 2 types of buildings in this game...

In case you don't believe me about the little glowing ball not being the source of the tesla bolts (ie, the thing that is used in calculating whether your little dretch gets blown apart or not), look at this:



"Bloody doctored shot!" You scream in fury. Well, that's what I said about those pics with the hooker, but Iowa didn't believe me either. No, truth is, I'm using the barrels here to block the taser-like fury of the tesla. Dretches have a surprisingly long reach...and I'm able to tag the edge of the bounding box again.

Ah, what the heck, as long as we're dispelling tesla myths...



What do we learn from this shot? Well, notice how the teslas aren't shooting me (the rant). That's because teslas do not shoot over turrets when placed on the same floor. Not even against tyrants, the tallest aliens. Not even if they get up right next the to turret and hug it. Not even if the tyrant jumps. It doesn't work. Why? Well, in this image I have noted the bounding boxes of the 4 structures. The center of the tesla is marked with a dot. Because this dot is obscured by the turret's bounding box, the tesla can't hit the rant. Have I emphasized that quite enough? Now, of course, this will work (in that the turrets and the teslas will shoot) if the aliens happen to be flying over this line. That happens, you know, fairly often with dragoons and maras and dretches...so it has its uses. Just realize that is the ONLY time it works.

Ok, so, what are teslas good for? Well, here we go on the whole turret vs. tesla thing:

Tesla Pros

• More damage per second. 32 compared to 26.67 (20% increase)
• No turning means no dodging for the aliens. You're in range, you're dying
• Tons of recoil means that small aliens literally get thrown away - dretches can't even get close enough to hit it unless they have cover.
• 30 more hp (210 vs 180, 16.67% increase). This means that goon pounces and rant slashes can't kill it in 2 shots. This does not effect rant charges or goon sniper shots, 2 shots is just exactly enough.
• Slightly smaller footprint means you can generally pack more into a small base
• No shadow region, unlike turrets. Makes it the choice for defending ledges

Tesla Cons

• Totally dependent on a working DCC for operation.
• Smaller range. It's not much, (250 compared to 300, 16.67% less), but it's there
• Larger bounding box. This makes it an easier target for everything, especially snipers, since it's larger vertically.
• Doesn't shoot around corners, contrary to popular belief.
• Doesn't shoot over turrets, contrary to popular belief
• Costs 10 BP instead of 8, or a 25% increase.

I think that's about everything about the comparison. Given all of this, the final verdict isn't clear. There ARE times when a tesla is useful. Teslas are ideal for defending against smaller aliens. Teslas are great for protecting bases that have very odd geometry or are on ledges. They are horrible against large aliens, even if they have a boost to health and damage. This is because any smart large alien will snipe the DC, which is large, easy to hit and only takes 2 shots. Then all of your teslas are nothing but alien barricades, just smaller, without creep and more techy looking. So, because of that I much prefer building turrets, and will do so in 98% of the games I play. I will occasionally pepper a base with teslas, one or two max, to make life difficult for the tiny alien players. I will never, EVER make a full-base defense system based on teslas. It's just foolish, because one, maybe two suicidal dragoon snipers will bring your base to its knees.

Reactors and Repeaters
I wanted a quick section in here on the RC and repeaters while I was thinking about it. Here is a screenshot from ATCS, taken from far outside the map.



The red circle shows the default location of the reactor. The green circle shows the range of a repeater if placed in the center of that red circle. The blue circle shows the range of the reactor. Now, perhaps you're wondering why the 'circles' are in fact egg-shaped. Well, that has to do with how ranges for RC/repeaters is calculated in 3D space, and is therefore a sphere, not a circle. So, as the elevation changes on the map, the distance to the RC/repeater changes and the apparent power range changes. Instead of showing discontinuities where the elevation changes suddenly and smooth curves elsewhere, I went with a funny egg shape that is continuous everywhere and accurate according to the sample points I took of the range. Believe me, this image was created after some painstaking experimentation, and is accurate. (Thanks liskey for the correction on my first explanation)

Seeing this, you may not realize a few things. First, the power for the RC by default extends a bit into the hallway. it also extends all the way to the outside. You can, in fact, place a ret on the dirt by the bunker, hugging against the wall closest to the RC. I would encourage you, oh noble future base builder, to learn all you can about default RC ranges. For instance, on a certain map that is in the default rotation you can place a turret right outside the alien base using the default RC's power range. If you're clever you can place a turret and a medi down before the aliens realize, then you spend the whole game just mopping them up... 1 bonus point to whoever names the map first... (liskey already got it...sorry folks!)

Conclusions
In conclusion, let's remember a few things. First, bases should lead to victory by making life easier for attackers, not defenders. Second, all bases need attention, all of the time. Third, no single strategy will always win. No single base defense is better than another. You have to learn how they all work together and you have to think every game. That's what makes it fun, that's what makes it hard, and that's what makes a great builder great.

This concludes the Basic Principles for Humans. I hope it was instructive. I would suggest you read through the next section on the tremulous.h file. It may sound like geeky compiler-talk, but it's going to be quite instructive...