Fire Simulation

As of version 0.5.0.0, BeamNG.drive supports the use of jbeam variables to drive a particle-based fire simulation. These variables can be combined to approximate the kind of fire behavior found in real vehicles. Fire can spread between nodes within a vehicle. Due to the way BeamNG handles vehicles on individually processed threads, spread of fire between vehicles is not currently supported.

1 Fire behavior
2 Jbeam Variables
3 Arguments
4 Diagram
5 Examples

Fire behavior

Nodes store both chemical and heat energy. Chemical energy can only be depleted as a node burns, and is converted into heat energy. Nodes lose heat to their surroundings over time, and this heat loss occurs more quickly at high airspeeds or when underwater. When a node burns, it gains heat energy and also radiates heat energy to nearby nodes, increasing their temperature. Nodes with high mass or high specific heat can absorb more heat energy per unit of temperature increase. This dynamic transfer of energy is what sustains a vehicle fire and allows it to spread or die down. The node variables controlling all of this are listed below.

Jbeam Variables

Arguments

Name	Default Value	Typical Range	Description
chemEnergy	false	50 - 2000	This variable specifies the amount of chemical energy, or fuel, in a node. For any given burn rate, this controls how long the node will burn for. Typically ranges from 50 (a few seconds) to 2000 (several minutes) at high burn rates.
burnRate	false	0.1 - 10	Controls the intensity with which a node burns. In physical terms, this refers to how quickly the node's chemical energy is converted into heat energy. Typically ranges from 0.1 (feeble flame) to 10 (intense fireball).
flashPoint	false	200 - 1000	A node with a temperature in degrees C greater than its flash point will begin to burn, radiating heat according to its burnRate. Typically ranges from around 200 degrees for gasoline, up to more than 1000 degrees for fire-resistant materials.
smokePoint	false	150 - 1000	A node with a temperature greater than its smoke point will begin to emit smoke particles.
specHeat	1	0.01 - 100	Specific heat - controls the amount of heat each unit of mass can hold. Nodes with a high specific heat can absorb more heat energy with little temperature increase, while nodes with low specific heat will quickly rise in temperature after absorbing only a little heat energy.
selfIgnitionCoef	false	0 - 1	Self-ignition coefficient - controls the amount of heat energy added to a node through impacts with surfaces. It is driven by the same physics that controls the emission of spark particles, so is a good choice for substances likely to be ignited by sparks (such as fuel). Since self-ignition merely adds heat to a node, whether that node actually ignites also depends on other factors such as specHeat and flashPoint.
containerBeam	false	"fuelTank1", "fuelTank2", etc	This variable can be assigned to both nodes and beams. Any node with a containerBeam value cannot be heated until a beam with the same containerBeam value is broken. This is useful for fuel tanks, preventing the volatile nodes inside from igniting unless the fuel tank is damaged.
baseTemp	false	200 - 1000	This variable sets a constant base temperature for a node, measured in degrees C. It is useful for hot elements such as exhaust manifolds, which may ignite other flammable nodes through direct contact.
conductionRadius	false	0.05 - 1	For nodes with a base temperature, the conduction radius is the range at which that node is able to conduct heat to other nodes. It is measured in meters.

Diagram

Diagram of flammable node locations in a typical car

To conserve CPU time and improve accuracy, the number of flammable nodes is usually kept to a minimum. Flammable nodes are generally found in the fuel tank area, along the length of the chassis or body, in the engine bay, and in the engine block. Spacing of flammable nodes should be considered when setting up node fire variables, as heat transfer between nodes falls off rapidly with distance.

Examples

In-line example:

	
{"group":"hatch_engine"},
        {"nodeWeight":11.16},
        ["e1r", 0.12, -1.62, 0.30,{"chemEnergy":500,"burnRate":0.39,"flashPoint":600,"smokePoint":550,"specHeat": 0.1,"selfIgnitionCoef":false,"containerBeam":false,"baseTemp":500,"conductionRadius":0.09}],

Persistent variables example:

	
{"group":"hatch_engine"},
        {"nodeWeight":11.16},
        {"chemEnergy":500,"burnRate":0.39,"flashPoint":600,"smokePoint":550,"specHeat": 0.1,"selfIgnitionCoef":false,"containerBeam":false,"baseTemp":500,"conductionRadius":0.09}
        ["e1r", 0.12, -1.62, 0.30],
        ["e1l", 0.12, -1.31, 0.30],
        {"chemEnergy":false,"burnRate":false,"flashPoint":false,"smokePoint":false,"specHeat": false,"selfIgnitionCoef":false,"containerBeam":false,"baseTemp":false,"conductionRadius":false}

Unless using in-line formatting, all variables should be reset to false when no-longer needed. Applying fire variables to more nodes than needed can reduce the accuracy of the simulation.

Vehicle Creation

Get started: Introduction to Vehicle Creation

JBeam

Overview	Introduction • Reference • Construction Guide
Physics	Nodes (refNodes) • Beams (Anisotropic • Bounded • Support • Pressured • L-Beam) • Coltris (Quads • Pressure Simulation)
Dynamics	DeformGroups • Engine Thermals • Hydros • Powertrain • PressureWheels • Slidenodes • Slots • Sounds • Superchargers • Turbochargers
Visuals	Flexbodies • Fires • GlowMap • Props (License Plates • Spotlights) • Skins

Extras

Blender Exporter plugin • Modeling and Texturing Guide • Vehicle Materials • Vehicle Specific Bindings

Upkeep

JBeam changelog • 0.8 Mod Conversion Guide • 0.8 Add-on Mod Conversion Guide • 0.8 Configuration Conversion Guide • 0.11 Mod Conversion Guide

Deprecated

HubWheels

See also: JBeam Examples • JBeam Physics Theory