This article represents an in-depth discussion about markers used by the AI. We'll dive into what markers there are and how they are most properly applied.
Parts
- About markers: AI markers (this article)
- About markers: pathing markers
Requisites
Map editing tools, such as:
Text editors such as:
- Notepad
The GPG editor is vastly outmatched feature wise on this topic. I recommend using the Ozonex editor for this topic and the article will only discuss how to approach this inside the Ozonex editor.
Personally I use Visual Studio Code as the text editor in this article. The exact same procedure applies for Notepad.
Markers
There are numerous markers available for various usages. The most common markers are the mass extractor, hydrocarbon and the blank markers used for spawn locations or objectives. More uncommon markers are the AI markers such as 'Naval Link', 'Rally Point' or a pathing marker such as 'Amphibous Path Marker'. These are markers that have no meaning to players, instead they have significant meaning to the various AI systems that players use to fight against and learn with.
Throughout this article we will dive into the AI markers. We'll discuss what markers mean to various AI's, how they could be placed in accordance and we'll dive into pathing markers and common misconceptions about them.
This article is written in collaboration with some of the developers of the AI community that surrounds Supreme Commander. In specific:
Markers used for understanding
Rally point
A rally point marker gives the AI an indication where it can send its units after construction when its not ready to be sent out yet. An example situation is when a platoon is being constructed. Until the platoon has been constructed, the units wait at the rally point marker.
This marker is used by:
- Vanilla, Sorian
There are two types of rally point markers:
- Rally Point: For air, land and amphibious units
- Naval Rally Point: For naval units
An AI will use the closest rally point marker to a factory as its rally point. A base can have multiple rally points given that it has multiple factories. Both land, amphibious and air units can rally to a land based rally point. Naval factories will look for the nearest naval rally point.
A few rally point markers on the map Withered Battle
Question: How are Rally Point markers used exactly? The current text (about platoons) is an assumption from observed behavior.
Question: Can a base have multiple functional rally point markers?
Question: Do air units have a rally point marker?
Question: Can Amphibious units use both rally point markers?
Expansion area
An expansion area marker provides the AI with an intuition as to where it can expand to. The majority of the AI's will construct a fully-fledged base or a support base at the location, depending whether or not it is a large expansion area. Such an area may include factories, generators, shields and defenses where applicable.
This marker is used by:
- Vanilla, Sorian, LOUD
It does not require mass extractors near it, but mass extractors near an expansion area marker may be preferred over ones that are not. By telling the AI to build a base at the location extractors can be automatically more secured from the perspective of a player.
Besides that it can function as a forward operation base to apply pressure on the enemy. The terrain surrounding an expansion area should be flat and large enough to support a range of buildings, including factories and shields.
Whether or not an expansion is a separately functioning base depends on its distance to the spawn location and other expansions. An expansion should be about 150 - 250 units away from other expansions in order for it to be a standalone base, depending on the AI at hand. Expansions that are close to each other may share their pool of units including engineers, causing odd interactions.
A few expansion markers on the map Open Palms
Question: Is there a difference between a large expansion area and an expansion area marker?
Question: Does an expansion area require extractors?
Question: Can expansion area's also construct naval factories if it is close to the water?
Question: Is there a minimal distance between expansions, or between the spawn and an expansion for it to be effective?
Naval area
A naval area marker provides the AI with an intuition as to where it can build a full-fledged naval base. This includes naval factories, naval and anti air defenses and a sonar.
This marker is used by:
- Vanilla, Sorian, LOUD
It requires a certain depth such that factories can be safely build and navy units can safely maneuver around the factories. Typically you want the marker to about 50 units off the shore such that a decent naval base can be constructed.
A naval base is much like an expansion but then with a focus on water. Units such as engineers may be shared with other expansions, depending on the direct (Cartesian) distance between the two. If such an interaction would be odd then place t the naval area marker at a sufficient distance from any other expansion area, including the spawn location.
A naval area marker that is far away from the spawning location to prevent odd interactions
A naval area marker that is close to the spawning location units can freely move up and down the beach and therefore interactions make sense
Question: Does it indeed include a sonar?
Question: Can other structures, such as generators, be constructed on land that is nearby?
Question: I recall that around the spawn location an AI make may naval factories, does this also hold for expansion area's near water?
Protected experimental construction
A protected experimental construction marker is quite literally what it says it is: a place where the AI can build an experimental in a relative safe manner.
This marker is used by:
- Vanilla, Sorian
An protected experimental construction marker at the back of the base in Field of Isis
Naval Link
A naval link marker is one of the markers that didn't have a meaning until one was given to it. The majority of the AI's will not take this marker into consideration.
This marker is used by:
- LOUD
It provides information on where a naval army can do bombardment on some target that is on land. The marker is expected near shores that are applicable for bombardment, significantly closer to the shore than naval pathing markers would be.
A bunch of naval link markers that are significantly more close to the shore than naval pathing markers on Mellow Shallows
Defensive point
The defense point describes where AI's can build support bases that do not have factories. At least defenses will be built and other structures such as air pads and shields depend upon the AI at hand.
This marker is used by:
- Vanilla, Sorian, LOUD
There are two types of defensive point markers:
- Defensive point: A land-based minor gun position, including anti air, tactical missile and point defenses.
- Naval defensive point: A naval-based minor gun position, including anti air, tactical missile and torpedo defenses.
The marker is particularly useful to protect entrances, allow the AI to utilize choke points more effectively or to allow an expansion to be more fortified than it would be on its own.
In the case of LOUD a base constructed at a defensive marker is considered to be a standalone base, given that it has sufficient distance to other expansions.
An expansion fortified with minor gun positions on the Varga Pass
Question: Can these also spawn other structures, such as generators, shields, or even factories?
Question: Is there a minimal distance between a defensive points and the spawn location or expansions for it to be effective?
Transport
Transport markers allow for alternative drop off points. There markers are optional. Typically transports use land pathing markers as their drop off points. Transport markers are considered when land pathing markers are either too dangerous.
This marker is used by:
- Sorian, LOUD
Transport markers are especially useful to mark positions that would be strange to include into the pathing graph, such as small islands. They can also be used to allow for more strategic dropping of units, such as behind a mass extractor somewhere.
A couple of red transport markers on the map High Noon
Question: Are these considered before the applicable pathing marker, or after?
Question: Can you place these on water for amphibious drop points?
Question: How about pick-up points, like the ferry function?
Island
Island markers are used to mark islands. In practice they are used in the most rudimentary way such that they are more commonly used as a flag to indicate that transports may be important on this map.
This marker is used by:
- Vanilla, Sorian, LOUD
These markers should be placed on each island once.
The island marker being used as a flag on Snoey Triangle
Question: These are barely used by the AI, correct?
Combat zone
Combat zone markers are used to indicate where we as a developer expect confrontations. This marker is poorly named as its main function is to be a target to which the AI can send out scouts. You can think of them as positions that need to be checked on a regular basis.
This marker is used by:
- Vanilla, LOUD
The marker should be placed at the center of paths from one spawn location to another or at remote hiding spots that are not intuitive for the AI but players may use.
A series of combat zones on the map Williamsons Bridge
Question: Are these also used to send out units?
Sources
For more information on how pathing markers are used:
About you
If you have interesting sources, approaches, opinions or ideas that aren't listed yet but may be valuable to the article: feel free to leave a message down below or contact me on Discord. The idea is to create a bunch of resources to share our knowledge surrounding development in Supreme Commander.
If you've used this resource for one of your maps feel free to make a post below: I'd love to know about it!__