COVER/OBJECT PLACEMENT AND MULTIPLAYER LEVEL DESIGN BALANCE
Niel Alphonso talk is talking about maximizing the effectiveness of cover placement, and overall multiplayer level balancing. This talk is aimed at FPSes and Third Person Shooters.
Covers offer protection and concealment.
There are three important things to remember about them:
- Overall movement times (meaning how long you're exposed)
- Sight lines (especially against the snipers)
- Combat distance (what optimal range do the weapon start to hit)
3rd Person Cover is easier than a FPS, and it has been here for years! Take for instance Space Invaders, it already has destructible covers!
The second example is Kill.Switch the game that has invented the traditional cover system we find in every self-respecting 3rd person shooter nowadays.
The demo video is a bit crude, there was a long way coming from this, but it kind of worked enough for this game. Niel shows some games that refined the concept, in the likes of Gears of War and Rainbow Six Vegas (hybrid 1st/3rd person perspective in cover).
The biggest issue with the covers is their close relationship with player metrics. And be advised metrics will change during the production! They always change anyway. That's why crates are here! (I can't believe he just said this!)
Crates are very effective in a production standpoint: they are the simplest shape to render. They tend to get used by the designers for their levels. They are modular: scalable and stackable. And they have a minimal CPU overhead.
It's also a solid base to outsource from. They work well with AI and cover systems (collision ray tracing is very expensive, so a simple shape is better). And since the 3D model is close to the actual collision mesh, it's definitely fast to compute.
Object Placement. There are three kind of objects:
- Dynamic physics
- Damage-inflicting objects
Each one got a few illustrative examples (Explosive barrels tower from Crysis, HL2's gravity gun).
Physics are close to reality, so it's easy for a human to apprehend the results. Damage inflicting objects are the cheapest way to get response from the environment.
Now Neil is talking about more elaborate environment responsiveness in form of elemental elements. He took Bioshock as an example for water you can interact as the player (freezing it with the matching plasmid power). He noted we also can interact with fire and oil pools, ice, etc.
In FarCry 2, the dynamic expanding fire system allows for rocks to be fire breaks. You have lot less control but you can still see the advantage. In Oblivion, you can use the day/night cycle to your advantage: wait for people to be asleep and rob them!
Multiplayer Level Balancing. There are two approaches here: using a symmetrical layout or an asymmetrical one.
Symmetrical layouts are obviously balanced from the start, but are fundamentally boring, since everything is the same, not to mention the difficulties knowing which side you're on (which I personaly do not agree with).
Neil took an old and noble Quake map as an example: the very popular, back in the days, DM6 a.k.a. "The Dark Zone". The placement of pickups gives it a really good flow.
The first seconds of the map decides the following events depending on which player gets the better pickup at the spawn (here, the Red Armor). Either the player with the lowest pickup could head to the room with the Rocket Launcher and Health, or to the room with the Blue Armor. He could also decide to go elsewhere and get the Grenade Launcher. Higher grounds in DM6 are very advantageous, but the bottom of the map is weighted by the presence of the Lightning Gun (but you are hinted someone is down there with the teleport sound). So power ups give weight to the different parts of t he map.
When going asymmetrical, you know it's going to be inherently unbalanced.. But you can still compensate by looking first at the overall movement times !! Objective-based maps are the best suited for asymmetrical maps. See De_Dust from Counter-Strike as a great reference. Here, movement times are crucial to define where is the first collision point.
Tip: use a ruler :) Neil points us to David "DaveJ/Ducks" Johnston's blog http://johnsto.co.uk/design/making_dust for more info of the makings of Dust.
But things get more complicated when you have asymmetrical maps AND asymmetrical gameplay. Neil tells us about ETQW. It was a real challenge for Splash Damage to balance the game. Both teams had different weapons, vehicles and abilities. ETQW maps were a linear example, and the local & global player rewards were there to widen it up. But in the end it just confused and turned off players. At the end of the day, even the maps played in competition were the simplest one, with no vehicles.
To balance a map, the first thing to look at is the playtests. You can then also look at the stats if you have the infrastructure to collect them. Neil recommends us a talk Valve did in 2009 explaining their approach to playtesting.
It is available here: Valves Approach To Playtesting.pdf
For instance, they give the overall stats for Team Fortress 2, with the winning percentages for all maps Red vs Blue. Strangely, 2fort is perfectly symmetric so the ratio should be 50/50. It's actually not the case! (see picture on slide 91).
There are also the deathmaps, which are showing chokepoints and most frequented areas, as well as balance errors. Bungie gives also deathmaps on their website. You can even play with filters to identify potential unbalanced areas.
Extra: Level Design Presentation Slides