Ground Unit Terrain Types and Modifiers

[nuclearslurpee (OP)]

I thought I would create this brief resource for people wanting to know which terrain types each ground unit combat capability applies to, since this information is not documented in a single place outside of the DB, and we have recently had a number of additional terrain types added to further complicate matters. I've also provided the actual combat effects of each terrain type since this information is relevant to ground combat. I have not provided the terraforming information to get these terrain types, since this is not a terraforming mechanics post.

Key to the data tables:

• Fortification Mod (modifier): The effect of fortification is multiplied by this factor. Therefore, terrain with a high fortification modifier tend to favor the defenders assuming they have had sufficient time to fortify, so an attacking force will need to increase the size of their force relative to the defending force as the fortification modifier increases.
• To-Hit Mod (modifier): The base chance to hit is multiplied by this factor. This affects attacking and defending units equally, so its main effect is to make combat take longer and thus require more supplies.
• (Combat) Difficulty: This is not in the DB. I have computed a metric which is simply Fort_Mod / ToHit_Mod which expresses how "difficult" combat is in each terrain type, mostly for attackers since defenders don't need to worry about the enemy's fortification in most cases.
• The last four columns indicate if a ground unit capability applies to each terrain type, as marked with an 'X'. Note that a single terrain type may have multiple applicable ground unit capability types. Remember that Jungle, Mountain, and Rift Valley capabilities apply to infantry only, while Desert capability can be applied to any base class.

A few interesting things to note:

• Due to how terrain types are encoded in the DB, a body cannot have both Mountain and Rift Valley terrain supertypes. It is possible to mix Desert, Jungle, and one of the other two types (although no "triple" terrain type exists in the DB at present).
• While each of the other terrain supertypes tend to make combat more difficult and more advantageous for the defenders, desert terrain types tend to make combat easier and less advantageous for the defenders.
• The most difficult terrain type to fight in is Jungle Mountain, followed by Mountain Rainforest.
• The most difficult terrain type to defend is Swamp, followed by the four 'plain' desert types (Arid, Cold Desert, Desert, and Hot Desert).
• The most common terrain supertype is Mountain (13/41), so if you are trying to decide which capability to research + develop first, Mountain is probably the safest bet in most cases. Desert (9/41) is the second-most common, with Jungle and Rift valley types making up 5/41 each.

As an appendix, I have attached three more images which contain the same data as above, sorted by fortification modifier, to-hit modifier, and the combat difficulty metric. You might find one of these more convenient for your purposes.

[Garfunkel]

To make this thread an all-around help for people, here's my understanding when the other modifiers kick in.

Low/High Gravity, Extreme Pressure and Extreme Temperature are not absolute modifiers but relative. As in, when they kick in depends on your species tolerance.



So as default humans:
Low Gravity modifier activates when fighting on a body with less than 0.10 G
High Gravity modifier activates when fighting on a body with more than 1.90 G
Extreme Pressure activates when atmospheric pressure on a body is above 4.00 atm - but does it kick in when there is no atmosphere? If yes, where is the cut-off point?
Extreme Temperature activates when average body temperature is either below -10.00 Celsius or above 38.00 Celsius

So, fighting on Luna, for example, would utilize ET and probably EP too but nothing else as default Luna is Barren, ie without terrain.

[Ulzgoroth]

Extreme Pressure activates when atmospheric pressure on a body is above 4.00 atm - but does it kick in when there is no atmosphere? If yes, where is the cut-off point?

Per its in-game description, it shouldn't kick in for low pressure at all.

Basically you want it (and high temperature obviously) to fight over Venus-like worlds. It might have wider use if your main species has a lower preferred pressure range?

[Garfunkel]

Eric, could we get this thread pinned either here or in The Academy?