Terra Invicta Dev Diary #11: Terrestrial Warfare

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johnnylump
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Terra Invicta Dev Diary #11: Terrestrial Warfare

Post by johnnylump » Sat Oct 17, 2020 5:19 pm

A lot of the councilor mechanics, control points and public opinion systems are there to simulate what strategists call “soft power,” where ideas and influence drive the fate of nations.
But “hard power” remains important too. In the Earth layer of Terra Invicta, it primarily manifests as armies.

As noted in previous dev diaries (and this DD may repeat some of what's in #4 and #5, which cover nation mechanics), armies represent significant concentrations of troops, machines and aircraft, along with a support system that allows them to occupy and hold a large amount of enemy territory.

Not a lot of modern nations can really pull that off at the scale we’re playing at, so most nations’ defense forces are abstracted into the nations’ regions. The current iteration of the 2021 campaign includes 6 armies for the United States, 4 each for Russia, China and India, and one each for the United Kingdom, France, Germany, Egypt, Iran, South Korea, North Korea, Pakistan, Turkey, and Israel.

Factions control armies by owning the control point they are assigned to. You can drive them around as you wish on friendly regions, although there is a cost-savings to leaving them in their HQ region. You typically can only use them to fight if your nation is at war, and that’s set by whoever controls the executive control point. Essentially, the nation’s executive determines if you can use them, but you control how - so, yes, you might hold your armies in reserve if the nation is pursuing a war you aren't particularly interested in supporting. That's the nature of nations under split control.

Armies have two primary stats that determine how they fight: miltech level and strength.

Miltech is a national-level stat you can increase via the national priorities mechanic. It is capped globally until some technologies are unlocked. The current value range is 0 to 7.99. In the 2021 scenario, the initial cap is 5.99 and all nations start somewhere in the 2s (Industrial Age), 3s (Atomic Age), or 4s (Information Age). Zero and one represent pre-industrial armies; they're there so the tech levels scale the way we want, and maybe reserved for future use if we ever order up some horsed cavalry art.

An Industrial Age Army:
army2.png
army2.png (205.63 KiB) Viewed 1826 times
An Information Age Army:
army4.png
army4.png (154.23 KiB) Viewed 1826 times
Strength measures how much damage the army has taken. Armies repair themselves when not fighting in a friendly region.

If at least two enemy armies are in the same region, they will fight. Mechanically, each army takes a shot once a day. Its chance of successfully damaging an enemy army is based on its tech level, strength, whether any councilors are lending their command attribute to the army’s nation via the Advise mission, and whether it on defense and the region has the "rugged" flag set.

If an army is in an enemy region and no enemy armies are present, it begins occupying the region, battling the local defense forces (who use the nation’s tech level) and taking damage from them. Badly damaged armies will attempt to flee to a safe place without you doing anything, but they can also be destroyed entirely when their strength reaches zero.

If a region is 100% occupied it ceases fighting, but it can’t change hands until the war is concluded.
Regional economies and space facilities can take significant damage during fighting -- although that goes down as miltech goes up (representing more precise weaponry). Sufficient damage will count as an atrocity by the army’s owning faction.

The way to win a war is to occupy the enemy’s capital region. At that moment, the war ends, triggering a regime change event. Claimed regions change hands to the occupier and its allies. If any of the invaded nation remains, its control point owners are replaced with those of the victor. Some of the nation's stats – like democracy and unrest -- change during regime change, sometimes in unpredictable ways.
Armies in an enemy region not engaged in a battle can also be used to strike space facilities directly or cause widespread economic damage there.

Human nations can support one army per region in their nation that doesn’t have a colony flag.

The aliens have their own armies. At some point in the game, these guys arrive by spaceship and function more or less like Earth armies. It's rather important you (if playing as the Resistance) be prepared for when they arrive.
AlienWalker_Final.jpg
AlienWalker_Final.jpg (55.45 KiB) Viewed 1826 times

…while these show up via another mechanic and just generally wreak havoc:
AlienMegaFaunaArmySpawn_Final.jpg
AlienMegaFaunaArmySpawn_Final.jpg (48.42 KiB) Viewed 1826 times


Armies are very expensive to build and maintain, and each army lowers the number of investment points available to a nation. (See Dev Diary #4 and #5). Armies are constructed by directing national investment into the Build Army priority.

Navies are flags that get added to an army via the Build Navy priority. Armies with a navy flag can cross oceans instead of only being allowed to move to adjacent regions. However, in wartime, a nation must possess naval superiority over its enemies to be able to travel overseas. A nation’s naval score is determined by multiplying the nation’s miltech value times the number of navies. Naval superiority is determined by which alliance has the higher sum of its naval scores.

In the 2021 scenario, all six of the U.S. armies start with naval flags. One Russian, Chinese and Indian army also has a naval flag, as do the U.K. and French armies.

Armies can also take damage in two other ways: Nuclear attacks, and orbital bombardment from fleets. Both are ... unpleasant ... for the army.

Note: Off-Earth "ground" combat -- with Space Marines and habs -- is smaller in scale and will be handled by a different mechanism, which will be touched on in future dev diaries.

Discussion: This system is fairly high-level relative to some of the other mechanics in the game. We’ve got the whole Solar System to cover, and army battles on Earth are just one part of that. In addition, engaging in large-scale ground warfare on Earth should be regarded as something of a failure, given the economic damage it causes.

That said, it’s an area we may consider expanding in the future, if we feel it will add to the game without dragging down the overall pacing or overwhelming the player (and AI) with management tasks.

The first expansion would be to add a better representation of naval warfare. The Earth map would be divided into sea zones, and navies would become distinct units on par with armies. Moving troops across oceans would be done via navies. This would be necessary if we ever took a stab at a World War II scenario.
It would also help us more realistically simulate modern nations with a relatively strong naval orientation in their defenses, particularly Japan.

The second would be adding a defensive or guards army type, probably represented visually by infantry instead of armor, that couldn’t enter enemy territory but instead would be useful as a mobile unit to help defend the homeland or allies during war. I can see regional power nations like Italy and Saudi Arabia having units like these.

Next up: We move into space! Space Development, Part 1, will describe the Solar System in Terra Invicta.

asaz989
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Re: Terra Invicta Dev Diary #11: Terrestrial Warfare

Post by asaz989 » Mon Oct 19, 2020 9:10 am

You mentioned how wars are won; but can they end without a victory? Especially in this kind of scenario where all wars are essentially proxy wars between players, I assume there are many prizes short of regime change (eg territorial changes, simple destruction of infrastructure) to fight for.

cranky corvid
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Re: Terra Invicta Dev Diary #11: Terrestrial Warfare

Post by cranky corvid » Fri Oct 23, 2020 9:01 pm

Wars can also end by a mutually agreed upon peace treaty, per dev diary 5. Though the diary did not mention whether concessions by one side or the other can be included in the treaty, or if it's always just a return to the pre-war status quo.

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