Igniting entities

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Igniting Entities

This tutorial uses an env_entity_igniter to light compatible entities on fire.

The Fiery Tool

First make a stick, (long, thin brush) tie it to a func_physbox (ctrl-t). I use a physbox so that our fire tool is like a "torch" you move with the Gravity Gun and +USE key

Class: func_physbox
Keyvalues		Comments
Name	physbox_pole	The name that other entities refer to this entity by.
Prop Data	None	If set, it will override this entity's health and damage taken from various weapons.

The Prop Data was no set because it applies health, and we don't want our stick to break. You may also want to set the spawnflag "Only Break on Trigger", so that it will not break unless told to. You may also want to set the "preferred carry angles" so the the stick always points the same way while being carried, something like (-5, 0, 90) is a good place to start.

It should look like this.

After you've created your physbox, you'll want to move the origin to end of the stick, because that's where the fire will sit once it is caught alight. The origin is a little circle in the 2D views, and a blue orb in the 3D views (only visible when the physbox is elected).

Tip:If you can't see it, go to View->Show Helpers

Next, make the env_entity_igniter, this can be placed anywhere on the map.

Class: env_entity_igniter
Keyvalues		Comments
Name	igniter	The name that other entities refer to this entity by.
Entity to ignite	!activator	Name of the entity to catch on fire.

The next entity we will need a is a trigger_multiple. put it on end of the pole, like an extension (or a fire).

Class: trigger_multiple
Keyvalues		Comments
Name	trigger_igniter	The name that other entities refer to this entity by.
Parent	physbox_pole	The name of this entity's parent in the movement hierarchy. Entities with parents move with their parent.
Start Disabled	Yes

It should look like this.

Make sure you set the trigger's spawnflags correctly I suggest checking the "everything (except physics debris)" and the "physics debris" box. ; )

The outputs of the trigger should be as followed:

"trigger_igniter" Outputs

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnStartTouch	igniter	Ignite	<none>	0.00	No

Setting the env_entity_igniter's target to "!activator" will make it ignite what ever triggers our trigger_multiple.

However, our trigger starts disabled, and out stick is not fire yet, hmm...

The Source Fire

Tip:This step is for added realism, complexity, and because I can. You can skip it, by adding a fire or a sprite to end of your stick, and starting the trigger enabled.

Make an env_fire entity somewhere on your map. Make sure set its spawnflags to your liking; I recommend at least "Start On" and "Infinite Duration". Then make another trigger_multiple around the fire.

Make this trigger exactly like the one on your stick:

It should look like this.

Trigger Outputs

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnStartTouch	igniter	Ignite	<none>	0.00	No

This will cause our stick (and more) to ignite, but not enable its own ignition trigger, so continue reading...

The spread

The simplest thing to do is to have our pole enable the trigger when damaged, like this:

"physbox_pole" Outputs

	My Output	Target Entity	Target Input	Parameter	Delay	Only Once
	OnHealthChanged	trigger_igniter	Enable	<none>	0.00	No
	OnHealthChanged	trigger_igniter	Disable	<none>	10.00	No

This way, when the pole is damaged, it enables the trigger (and lets you burn more things) for 10 seconds, which is the default flame lifetime set by the env_entity_igniter. Unfortunately, now the pole will enable the trigger when it takes damage in any way! To fix this we will use a filter_damage_type

Class: filter_damage_type
Keyvalues		Comments
Name	filter_burn	The name that other entities refer to this entity by.
Filter mode	Allow entities that match criteria	If set to Allow, only entities who match the criteria will pass the filter.
Damage type	BURN	The damage type to filter by.

Make sure you set "physbox_pole"'s keyvalue "damage filter" to "filter_burn".

Victims

• A nice place to start is a func_physbox, since you already know all about them from trying to understand my tutorial ; )
• The next step up would be to use a prop_physics (Pick a model that breaks!). I like "models/props_junk/wood_crate001a.mdl"
• An interesting entity is the func_breakable because it does not "catch" fire. You will need keep a fire close by to constantly supply damage until it breaks.
• A fun one is the prop_ragdoll. Since they do not break, they can be re-lit many times.
  • A cool model might be: "models/zombie/classic_torso.mdl" or "models/zombie/zombie_soldier_torso.mdl".
• Of course, the most tempting option is an NPC, but they can be the hardest to successfully implement.

A note about NPC's

• reaction
• relationships
• path nodes

Conclusion

Don't forget to make a player start, a gravgun, and other things like a suit (or maybe a healthcharger).

Your finished map should look like this:

Here are some shots of the effects in the game:

Wrap up

Feel free to play around see what works, hopefully this article have stimulated your imagination.

• The example used in this tutorial.

Credits

• The tutorial was created by Bit Mage 14:37, 21 Mar 2008 (EST)