Entity limit - Revision history

Amadeus: /* Entity Limit in Doom3/TDM */

2024-05-30T17:19:14Z

Entity Limit in Doom3/TDM

← Older revision		Revision as of 17:19, 30 May 2024
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	* Doom 3: '''4096'''		* Doom 3: '''4096'''
	* The Dark Mod: '''~~8192~~'''		* The Dark Mod: '''65,536''' (as of TDM 2.10, the entity limit was raised from 8,912 to 65,536)

	~~While it is possible to raise~~ the entity limit ~~further~~, ~~this is not really a good idea~~, ~~and not planned at the moment.~~

			While it is possible to raise the entity limit further, this is not really a good idea, and not planned at the moment.

	== "Invisible entities" ==		== "Invisible entities" ==

Petike: adding category tag

2018-10-21T01:59:16Z

adding category tag

← Older revision		Revision as of 01:59, 21 October 2018
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	{{editing}}		{{editing}}
	[[Category:Entities]]		[[Category:Entities\|L]]

Petike: adding category tag

2018-10-21T01:57:13Z

adding category tag

← Older revision		Revision as of 01:57, 21 October 2018
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			[[Category:Entities]]

Tels: update

2011-03-11T06:20:36Z

update

← Older revision		Revision as of 06:20, 11 March 2011
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	== "Invisible entities" ==		== "Invisible entities" ==

	There are some entities that ~~are~~ counted ~~into~~ the limit, even tho they are not really "visible" to the mapper~~, but you still need to count them against the limit~~. This basically means do not build a map that is too close to the limit, leave ~~quite a bit space (like~~ 100 entities) so the game can work:		There are some entities that counted against the limit, even tho they are not really "visible" to the mapper. This basically means do not build a map that is too close to the limit, leave at least 100 entities so the game can work:

	* the worldspawn (all map geometry) counts as 1 entity		* the worldspawn (all map geometry) counts as one entity ("entity 0")
	* the player itself		* the player itself
	* arrows spawned when the player shoots an arrow		* arrows spawned when the player shoots an arrow
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	* arrow results (an invisible entity that makes guards investigate arrows sticking into walls)		* arrow results (an invisible entity that makes guards investigate arrows sticking into walls)
	* items dropped from the player inventory (keys, readables) to the world		* items dropped from the player inventory (keys, readables) to the world

			There are also entities that you will likely use, and you need to reserve space for them in the typical map:

			* the main ambient light
			* if you are using the zone system: one global entity plus one seperator for most portals
			* starting items and items in the players inventory


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	* CPU time during runtime, because some operations need to filter through all entities just to find their entities. F.i. an AI that wants to check if there is another AI needs to run through all existing entities to find them. The more entities your map has (say 7000 vs. 700) the longer that takes. Note: This time is very small, but it can add up if you have a really high entity number. This is the main reason why you should save entities and not just ask us to raise the entity limit.		* CPU time during runtime, because some operations need to filter through all entities just to find their entities. F.i. an AI that wants to check if there is another AI needs to run through all existing entities to find them. The more entities your map has (say 7000 vs. 700) the longer that takes. Note: This time is very small, but it can add up if you have a really high entity number. This is the main reason why you should save entities and not just ask us to raise the entity limit.
	* CPU time thinking (unless the entity is dormant)		* CPU time thinking (unless the entity is dormant)
	* GPU time during drawing if the entity is visible		* '''GPU''' (graphic card) time during drawing if the entity is visible

	The entity limit itself does not use any mentionable resources, e.g. if we would raise the entity limit from 8192 to 16384 would not use up any more resources. Only entities actually spawned use resources.		The entity limit itself does not use any mentionable resources, e.g. if we would raise the entity limit from 8192 to 16384 would not use up any more resources. Only entities actually spawned use resources.
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	== See also ==		== See also ==

	* [[~~LODE\|Level of Detail Entity~~]] - how to overcome the entity limit		* [[SEED]] - how to overcome the entity limit

	{{editing}}		{{editing}}

Tels: first stab

2010-12-01T06:45:33Z

first stab

New page

== Entities? ==

An '''entity''' is the basic ''object'' in the idTech4 engine. This can be something visible (a chair, a light), or invisible (a trigger), or global objects that are there just to make your map work (the worldspawn, ambient light etc).

Each entity added to a map uses up a certain amount of memory, and needs quite a bit of time to "spawn".
So having many entities makes your map load slower and use more resources.

== Entity Limit in Doom3/TDM ==

The idTech4 engine limits the number of '''entities''' in a map to a certain fixed amount. These are:

* Doom 3: '''4096'''
* The Dark Mod: '''8192'''

While it is possible to raise the entity limit further, this is not really a good idea, and not planned at the moment.

== "Invisible entities" ==

There are some entities that are counted into the limit, even tho they are not really "visible" to the mapper, but you still need to count them against the limit. This basically means do not build a map that is too close to the limit, leave quite a bit space (like 100 entities) so the game can work:

* the worldspawn (all map geometry) counts as 1 entity
* the player itself
* arrows spawned when the player shoots an arrow
* broken arrows or other flinders spawned when objects get destroyed
* arrow results (an invisible entity that makes guards investigate arrows sticking into walls)
* items dropped from the player inventory (keys, readables) to the world

== Resources used ==

Entities that spawn use up the following resources:

* CPU time uring spawn (and during destroy). So avoid constantly spawning/destroying entities, that can be very costly (f.i. an arrow trap that shoots an high amount of arrows that than later disappear)
* CPU time during runtime, because some operations need to filter through all entities just to find their entities. F.i. an AI that wants to check if there is another AI needs to run through all existing entities to find them. The more entities your map has (say 7000 vs. 700) the longer that takes. Note: This time is very small, but it can add up if you have a really high entity number. This is the main reason why you should save entities and not just ask us to raise the entity limit.
* CPU time thinking (unless the entity is dormant)
* GPU time during drawing if the entity is visible

The entity limit itself does not use any mentionable resources, e.g. if we would raise the entity limit from 8192 to 16384 would not use up any more resources. Only entities actually spawned use resources.

== Reducing the entity count ==

You can reduce the entity count in your map by:

* combine multiple func_statics into one, if possible. This brings the most benefits, as it also improves [[rendering performance]].
* remove entities at the border of the map and replace them with decals (f.i. distant trees). This also improves [[rendering performance]] since a decal is only 2 triangles, while a tree might be 100..1000s of triangles.
* instead of having multiple '''atdm:ammo_XXXarrow''' entities that are given to the player at map start, create only one and set the spawnarg "inv_ammo_amount" to the desired amount. These entities are removed at map start anyway, but this way they don't count against the overall limit while loading the map. Not having to spawn 10 arrow entities is also faster while loading your map.

== See also ==

* [[LODE|Level of Detail Entity]] - how to overcome the entity limit

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