blizzard Company of Heroes Contributors Game Design Games RTS101 Technology

More Mechanics: Weather and Terrain

Recently I’ve had some great discussions about various real time strategy mechanics that have popped up a few times but went away. I really enjoyed the conversations so I decided to write a series about them and try and build on my thoughts. I’ll be calling the series “More Mechanics” and hope to look at a few design ideas and mechanics that I’d love to see expanded on. These may be older game mechanics that have gone extinct or new ones I hope other developers test or try and incorporate. In this inaugural article I’ll be rambling abit about weather and terrain and how they have been used to impact game play. Now this won’t be an exahustive history of terrain and weather in real time strategy games, rather is will look at a key few examples and my hopes for the future.

Now of the mechanics I will be looking at, I believe that weather, and to a lesser extent terrain types, are the newest. I doubt this is due to creativity or developers not thinking of it earlier: this is likely tied to technological limitations. Even cosmetic weather wasn’t added to most RTS games until a half decade ago or so likely from to the impact it has on performance. Due with the rise of more powerful processors and video cards we saw the first game to tackle weather as a factor was Company of Heroes 2. Relic designed their sequel to their masterpiece at the perfect time and with the perfect setting.

CompanyofHeroes2_MP_Online_CityCombat“Remember when that was a nice bakery?”

When it comes to a game’s mechanics, I love when a game developer gives a reason for why that mechanic exists. Creep in the StarCraft series is a mechanic for the Zerg race designed to limit base construction on a layer that spreads around the map via a certain type of structure. Buildings, aside from the Hatchery, which is the center of the Zerg base, can only be built on Creep. Blizzard gives the reason for its existence by saying the Zerg structures need the Creep to survive as they are themselves alive and draw nutrients from the Creep.

In the Age of Empires series you have more resources than the standard RTS but because they are historical games and the resources are items such as gold, stone or food, it makes sense in the context of the game. Not all games need to justify their mechanics through lore or setting, but I respect a developer that does this. This topic deserves a post of its own, so for now let’s look at how Company of Heroes 2, and other games, started using varying terrain types.

The idea of programming different terrains was a fundamental idea very early on in real time strategy history. Dune 2, for example, used terrain as a way to separate your base from the wild beasts of the world (and from the resources you harvest! – wayward), wander too far into the sands and you might start losing units. It was a fun way to instill fear into the player.

Blizzard’s games have had map terrain where some areas couldn’t be built on at all, by either side. (I believe Total Annihilation utilized height advantage for units on high terrain, War Wind hid units inside of treelines, terrain variation has always been a goal of RTS developers, I think – wayward). When the technology came around 3D RTS games began to see development which added great sense of scale through the ability to add height to games. Starcraft gave a bonus to units on high ground while many games started adding naval and air combat (WarCraft 2 had naval combat. StarCraft bonus to units on high ground was ‘they can’t be seen’ – Total Annihilation had IIRC damage or range bonuses to units on high ground – wayward). As games began exploring adding new layers to the game map we saw the value of terrain increase.

WiC IslandSeems like a nice island until the paratroopers land

With this new technology we’ve seen some amazing new mechanics build off the design of varied terrain. Line of site as a mechanic changed with hills and valleys, bridges didn’t have to be meaningless chokes and you could have some units circumvent them. A game like World in Conflict wasn’t the first to bring amphibious vehicles to the RTS genre but it did help take it to a new level of importance with islands, rivers and lakes. These new units ability to interact with the terrain was amazing, the depth of water impacting gameplay.

At the same time developers were toying and working with the idea of garrisonable buildings and environmental destruction. While existing prior to the early 2000s (I think Tiberian Sun and Red Alert 2 did this? It’d be good to know of RTS that did this early. Also, War Wind had garrisonable structures and units could capture and pilot vehicles – wayward), games like Command and Conquer: Generals saw neutral buildings become a vital part of gameplay and also be interesting. Cramped cities could become battle fields and towns would be flattened wastelands by the end of games. Factions could burn troops inside buildings while another faction could drop infantry into occupied builds from helicopters. These ideas altered map design.

Generals BuildingsGenerals brought newfound importance to cities

Game developers continued to innovate on this front and eventually even the ground and terrain gave way before the might of the player. World in Conflict and the first Company of Heroes helped shape the physics and game engines that allowed for the player’s actions to alter the world they played in. Craters from artillery became cover that didn’t exist at the start of the game, bridges were destroyed, buildings collapsed on troops and cities feel through these games. This level of physics have altered how many real time strategy games are designed, impacting most new games released from Act of Aggression to the fluid maps of the new Homeworld.

Relic, possibly the masters of terrain manipulation, took the genre and RTS game engines to a whole new level with the release of Company of Heroes 2 in 2013. Building on their amazing engine found in the first game they added greater detail and impact of explosions, trees would shatter from bullets, building damage became more realistic and most importantly, they added ice. Water in recent years was a powerful mechanic by itself, impacting bridge location, unit types that ford it or had to avoid it and combat (Tiberian Sun and RA2 had bridges that could be destroyed and rebuilt – wayward). Company of Heroes 2 took rivers and added the ability to for them freeze over, allowing all units to cross them. But with this new mechanism came the fact players could break the ice. See a river freeze over and know your enemy will try and flank you across the new passage ways? Plant a few mines and watch as their tanks sink to their doom.

Company-of-Heroes-2-E3-2013-3-1024x682“We didn’t need that tank did we?”

It was amazing the first time I saw my trap spring open and cost my opponent the skirmish and had a powerful influence on any winter map. Combine these with snow banks that slowed infantry and you can see how Company of Heroes 2 is really the best example of player-terrain interaction in any real time strategy game so far. It also helps us look at the next, and really newest, game to use weather.

Now since weather in RTS games is an entirely new production this won’t be too long but in Company of Heroes 2 they added weather to winter maps. It’s largely a single player experience, though some multiplayer maps and mods use it, but on certain maps you will be fighting in, or one will appear at times, snow storms. If you recall at the beginning of this article I mention how I love developers that justify new mechanics within the lore and setting of the game?

Company of Heroes 2 makes this snow storm idea logical because it spends most of it’s campaign in Russia during the winter. During World War 2 hundreds of thousands of Germans and Russians froze to death during the battles on the eastern front. This idea of snow storms and winter being deadly fits within the games ethos. How the game translates this fear of the cold into the game is quite smart. During these storms the units vision is reduced and they slowly begin freezing to death if they remain outside too long. Units need to either find shelter in buildings or discover campfires to warm themselves. This forced players to come into natural conflict with each other as they both fought for limited warmth, essentially creating a new resource on the map. This also changed the dynamics of smart play and risk-reward in matches, over time. This is huge, very few other games attempt things like this.

Company-of-Heroes-2-Dead-Snow“They aren’t dead, they are just taking naps under snow blankets.”

Now this idea of weather as a game factor is very, very new and actually terrain as a factor is only about a decade old as well, outside of the change from 2D to 3D. This is largely unexplored territory but a unique one. Many new mechanics arise from creativity but terrain and weather effects are almost entirely tied to the technology of the era. As processors improve, RAM numbers explode and video cards get more beefy, I expect these ideas to be expanded on and I am extremely excited for that time.

I do wanted to make one point before ending, not all real time strategy games rely on these mechanics, actually many of the best don’t, but that is fine. Like with all real time strategy mechanics, from unit AI to cover to resource management, all games don’t need to be alike to be of high quality, a variety of styles and factors make the genre better. While I love this idea, excluding weather or player-terrain interaction won’t turn me off, heck the RTS occupying my time right now, Starcraft 2, has no player-terrain interaction and that is fine. What developers include or exclude isn’t as important to me as the quality of the game.

Additional notes: Earth 2150 had a separate terrain layer, tunnels under the ground. Tiberian Sun burrowing tank could ignore cliffs and other terrain. Earth 2150 had hover units that could ignore some terrain but were still targetable by most ground units. I think TA had this, too. Could be interesting to note how units have different reactions to terrain types. Etherium had different weather events on different tilesets, each map had unique weather considerations. Dune series had Sandstorms and different types of Sandworm attack.


  1. Actually, line of sight being impacted by the terrain dates back to 1997 with both Dark Reign and Total Annihilation using a true line of sight system equivalent to CoH2 (terrain blocks vision, so do structures, trees and so on). Many games like, say Original War, also used such a system and in general, it was absent only in the big 3 (Westwood, Ensemble, Blizzard) and the games which were carbon copies of them.

    Starcraft was slightly more complex than most people give it credit for in this regard. Units on the low ground, when firing upwards actually receive a 50% miss chance. There is also a cover system implemented for doodads so units hidden in a tree-line also get a bonus, though I don’t remember the specific miss percentage against them.

    The next big thing was a day/night cycle and the first game that claimed to try it was Tiberian Sun. Only what followed was a rushed release and the game only retained day/night stuff for specific campaign missions. It did, however, implement the Ion storms which are the first instance of real, unpredictable weather in an RTS. You lose your radar, all flying units must remain on the runway (thos still in flight when the storm hits crash) and there’s lightning striking all over the map.
    Tiberians Sun was also the first to implement garrisonable buildings, but the nature of the game’s landscape meant it was mostly a gimmick with no real use. Ditto for amphibious APCs. This was all back in 1999.
    Red Alert 2 addressed the gimmicky nature of garrisons and they are actually useful, unlike in Generals where the inclusion of instant kill ways of disposing of them meant that they are absolutely no good outside of singleplayer.

    The first game to actually handle these things was Earth 2150. Full day/night cycle, weather system, true line of sight and much more.
    The game had it all back in May 2000.

    Ground Control, released a mere few days after Earth 2150 boasts all the nuances that CoH inherited from 2004’s Dawn of War regarding dynamically created cover with craters and such, directional armour, line of sight/fire implemented in much the same way as the recently released Deserts of Kharak (most games had it, but this one places emphasis on these systems, just like the new Homeworld).

    So 2000 is the year you’re looking for as the definitive time when weather and such were the new thing in RTS games.

    The big 3 never got around to implement all of this.
    Tiberian Sun had weather but left out night completely and by Red Alert 2, Westwood abandoned that vision.
    Age of Mythology (2002) was Ensemble’s answer to this and just like Tiberian Sun before it, the systems were cut out, in the end trashing both the day/night cycle and weather.
    Last to the party was Blizzard’s Reign of Chaos also in 2002 which implemented the, for a while ostensibly copied day/night system with reduced vision and NE nightwalk but it had no weather to speak of and Blizzard went as far as to remove the day/night cycle from WoW after a while. They also completely abandoned any hopes for it by 2008 and Starcraft 2.

    This trend can also be seen nowadays.
    If you look at the promotional material of Act of Aggression, one of the promised features was a day/night cycle but by the time of game’s beta, it was dropped completely.

    Liked by 1 person

    1. If you mean World of Warcraft by WoW: There is a day/night cycle and the nights are actually darker then before.


  2. Tiberian Sun had freezing rivers, too!

    In the end, all of this stuff does not seem new.

    And, “Dark Reign” was VERY ahead of its time, IMO. It was the perfection of C&C gameplay, just not as atmospheric and well-polished.


  3. Not a single mention on Empire Earth 2 dafuq
    This was back in 2005:

    Empire Earth 2 also mixes in weather into the game. It doesn’t simply serve as eye-candy or atmospherics. But also effects the way the units behave in the game. Poor weather will make troop movement over land more difficult and reduce their line of sight, or make arial attacks impossible.


  4. I would agree with several commentators, weather and terrain have appeared in rts games earlier than Topher thinks, though it often hasn’t been one of the big features.
    One game that had tons of terrain interactions was Praetorians, by Pyro studios. In it infantry and archers could enter forests, where they would be hidden from outside enemies, or the latter could fire down from high ground unseen. Most cavalry couldn’t enter forests and since they covered much of the map it could be turned into an interesting nuance to movement. Finally, grass hid units when they were still and could be burned by archers to get rid of it. I could see a similar mechanic incorporated with a faction that gets greater terrain bonuses, like dryads or elves. Give them a way to reseed those plants and you could see something like creep spreading.
    One thing I disliked about Dawn of War 2 was that vehicles were not precise in their movement and often blew straight through cover when I wanted it to be intact. Then again, I’ve noticed DoW2 lacked a lot of quality of life features, like reverse move on vehicles and even the shift key. If cover is made destructible by unit movement it’d be nice if they could trundle around somewhat precisely.


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