From: metro Chicago, Illinois, USA
Coder Diary #29 -- The New Air Model
In the Campaign Series universe, time marches on. Or should I say: time flies on?
Helicopters! These were first mass-produced in the middle of WWII, but were used primarily for rescue in out-of-the-way places with harsh terrain. Helicopters effectively play no role in the earlier JTCS trio of WWII games.
But beginning with the Korean War, and especially for our forthcoming game, Middle East, all that has changed. Helicopters -- and also SAMs (Surface-to-Air Missiles), other forms of AA (anti-aircraft) weaponry, advanced guidance systems, etc. -- these play an increasing part in the Middle East conflicts, particularly those of the 1970s and later. (And helicopters will play a pivotal role in our next Vietnam game, obviously.)
The Campaign Series battle space is no longer flat, with limited consideration of air space. The Campaign Series is fleshing out the third, vertical dimension!
So how does the new Air Model work?
Some unit types, helicopters most especially, can operate in any one of four separate Air Levels:
Nap of Earth, or NOE
As the code explains it:
#define ELEVATION_HIGHAIRLEVEL 750 // 3 "hexes" high; 250 meters above High Air Level's 500 meter base height
#define ELEVATION_LOWAIRLEVEL 250 // 1 "hex" high; at mid point of 0-500 meter Low Air Level
#define ELEVATION_NOEAIRLEVEL 25 // minimal height advantage, over fields, rough & marsh, etc.
#define ELEVATION_GROUNDAIRLEVEL 0
That is obviously a simplification, those are obviously abstractions. We are not transforming The Campaign Series into a flight sim! We are also not expanding the role of tactical fixed-wing aircraft. Fixed-wing aircraft will operate and function much like they have in the JTCS games. Few changes there. (But with an expanded role for direct player-controlled fixed-wing aircraft ops in Vietnam, and future games. Still simplified and abstracted, though.)
Here is a screenshot of four helicopter units in the four different Air Levels:
As you can see, we indicate the four Air Levels by the H/L/N/G markers in the unit Info Box, between the Action and Assault labels to the right. You will also note the color coding, from G[round]'s green, to N[OE]'s yellow, onto L[ow]'s & H[igh]'s light and dark sky blue.
To the left of the screenshot, you see where you can direct a helo to Ascend or Descend one Air Level by selecting the appropriate menu choice. (Hereinafter, I will use the short-form "helo" instead of "helicopter, for brevity's sake.) You can also use the hot keys PgUp or PgDn. At screen bottom, in the Tool Bar, you will also note the up and down light blue arrows for this purpose.
Important: You can only ascend or descend once per hex. You can't ascend (or descend) a helo, then without moving to another hex, ascend (or descend) in the very same hex. No steep ascents or descents (like a dive bomber) in the same hex allowed! As your helo units ascend and descend, they will have to move across the map as they do, in effect ascending and descending in shallower trajectories and flight arcs.
Exception: You can descend/ascend to/from Ground in the same hex! (Else otherwise, how is a helo supposed to move horizontally or vertically to a different map hex? By taxiing across the ground? Um, no.)
High vs. Low vs. NOE vs. Ground
So why would you want to fly High, or Low, or NOE?
Obviously, you can't fly at all unless you ascend up from Ground Level.
Here are a list of the differences among the various Air Levels:
High: fastest flight; flies in a straight line ("as the crow flies"); enjoys greatest Visibility; can't fire at ground units, but can fire at enemy helos at Low & High Air Level; impervious to normal ground fire; but still vulnerable to AA fire, especially SAM fire.
Low: medium speed (2/3 High Level speed); flies in a straight line ("as the crow flies"); has reduced Visibility; can fire at ground units, and vice versa.
NOE: slowest flight (1/3 High Level speed); flies in and around ground obstacles (because helos at NOE are "hugging" the ground); has much reduced Visibility (because of LOS blocking terrain); subject to all forms of fire, except for fire from helos at High Level, and SAMs.
Ground: no movement at all, except to ascend; Visibility same as for other ground units; subject to all forms of ground fire; but impervious to AA, SAM, and high-flying helo fire.
Other factors: It costs more APs (Action Points) to ascend than to descend. Units firing up suffer a malus in the combat strength; units firing down suffer no such malus.
And other factors. The above is not an exhaustive list. Please see the Manual for details.
If flying High is fastest and is impervious to most forms of ground fire, why not always fly High?
Well, high flying helos can't fire at ground units, or other helos at NOE. Also, watch out!
High flying helos can still be hit by AA fire, and are especially susceptible to SAM fire.
Why would you fly NOE, since it is 1/3 the speed of flying High? For protection mainly. You can use ground obstacles (and smoke) to creep up on the enemy, with reduced chance of drawing opportunity fire, or direct fire (when it's the other side's turn).
Obviously, carrier helos need to be at ground to off-load their passengers:
Flying Low has its advantages too. Flying Low, you can fire up or down, and move at a reasonable speed.
All of these choices and trade-offs make for some very interesting game play. Helo ops are fun!
Can helos overfly enemy ground units, even share the same hex with other enemy helos? Why yes!
Can helos fire at ground units in the same hex, and vice versa? Why yes! Can helos even "dogfight" against other enemy helos sharing the same hex (a very rare occurrence)? Absolutely!
Air Level Visibility
At Ground level, helos have the same Visibility as any other ground unit.
As a helo ascends, it enjoys greater Visibility -- it can see farther.
Here is a screenshot of a helo unit at Low Air Level (with the '.' hot key toggled to display hex elevations):
Visibility extends out 8 hexes in all directions, because the Visibility for this scenario, for this turn, is generally set to 8 (see the Info Box). Note how the helo is overflying ground at elevation 2, but because it is flying above ground, it can see over the higher elevations (relative to 2) 3 & 4 at HILL 55 and beyond. And similarly, in other directions, it can see hexes that a normal ground unit would not be able to see, due to the intervening LOS blocking terrain (for ground units).
Except note the two magenta highlighted hexes to the east/southeast. The drop in ground elevation there is precipitous from 3 to 1. The geometry of the situation is such that the helo can see around those two hexes, but the contents of those two hexes are hidden from view. If the helo were to ascend one Air Level to High, yes, it could then see those two hexes, and all other hexes out to an 8 hex radius.
Here is a screenshot of a helo unit at NOE:
Note how surrounding ground obstacles -- town hexes, orchards, high walls, even other enemy units -- obstruct Visibility.
Let's try ascending those helo units to Low Level:
Now the helo at Low level, but still in the very same map hex, can see the full 8 hexes outward in all directions.
But wait? "The helo". What happened to the second helo unit? And how did the first helo unit become Disordered? It's because the act of ascending drew opportunity fire, which destroyed the one helo and disordered the other!
Moving forward in time from WWII, it was essential that we support helo ops, and it follows that we had to implement the new Air Model.
There are other interesting features of the new Air Model, for instance:
Various forms of AA are at half normal range.
SAMs may fire against helos only between 16 hexes and 80 hexes distant.
SAMs may fire against helos (also by implication, airstriking aircraft) at High Air Level only.
Units assessing opfire at passing airplanes are 1/4 less likely than normal to, in fact, opfire.
Units without SAM or AA capabilities attack at half the effectiveness against passing airplanes.
Combat results don't cause helos to retreat.
Aircraft eliminated by opfire have a 25% chance of delivering payload before elimination.
If opfire disrupts airstriking aircraft, there is reduced chance (down to 85%) it will drop payload.
If opfire eliminates airstriking aircraft, this counts against the VPs for the aircraft losing side.
And let's not forget the new helo ATGM (Anti-Tank Guided Missile) resupply system. ATGM helos have four shots. They use them up, they must return to their parent HQ unit and land in order to resupply. No, unlike normal ground supply, airborne helos will not somehow mysteriously resupply in mid air. They can't just endlessly hover above the battlefield and fire their missiles without limit. The Air Model rules will have them act sensibly.
And other stuff. More than I want to describe here. See the Manual for details. Also observe the Status Bar messages as you attempt this or that.
The Air Model: It's a new system; it's a rich, nuanced system; it's fun! We hope you will like it!
(Alas, some bad news: There was insufficient time to program the game's A/I to consider helo ops. For scenarios with helos -- in Middle East, less than 1/5 of them, in most of those with helos only playing a minor role -- if you are playing human vs. A/I, you will want to play the helo-enabled side. Otherwise, the A/I side will operate helos much like ground units (never ascend/descend, never move to ground to unload passengers, has no knowledge of the advantages/disadvantages operating in the various Air Levels, etc.) The helo A/I -- will be added in some future Middle East update, and in the future Vietnam game (etc.) for certain.)
Until the next time...
< Message edited by berto -- 9/9/2015 7:40:26 AM >