Smoke Flow Object

Reference

Smoke Flow objects are used to add or remove smoke and fireto a Smoke Domain object.

To define any mesh object as a Smoke Flow object, add smoke physics by clicking Smoke_in Properties ‣ Physics. Then select _Flow as the Smoke Type.Now you should have a default smoke flow source object. You can test this by playing the animationAlt-A from the first frame. If your source object is inside your domain, you should see smoke.

Options

Smoke Flow options.

Flow Type

• Fire
• Emit only fire. Note that the domain will automatically create some smoke to simulate smoke left by burnt fuel.
• Smoke
• Emit only smoke.
• Fire + Smoke
• Emit both fire and smoke.
• Outflow
• Remove smoke and fire. Note that the shape of the outflow will use the object's bounding box.

Flow Source

• Source

• This setting defines the method used to emit smoke and fire.

  • Mesh
  • Create smoke/fire directly from the object's mesh.With this option selected there two additional settings, Surface and Volume.

Surface

Maximum distance in voxels from the surface of the mesh in which smoke is created (see voxel).Since this setting uses voxels to determine distance,results will vary depending on the domain's resolution.

Volume

Amount of smoke to emit inside the emitter mesh, where 0 is none and 1 isNote that emitting smoke based on volume may have unpredictable resultsif your mesh is non-manifold.

• Particle System
• Create smoke/fire from a particle system on the flow object. Note that only Emitter type particle systemscan add smoke.See Particles for information on how to create a particle system.

With this option selected, there is a box to select a particle system and one additional setting, Set Size.

Set Size

When this setting is enabled, it allows the Size setting to definethe maximum distance in voxels at which particles can emit smoke,similar to the Surface setting for mesh sources.

When disabled, particles will fill the nearest voxel with smoke.

• Initial Velocity

• When enabled, smoke will inherit the momentum of the flow source.

  • Source
  • Multiplier for inherited velocity. A value of 1 will emit smoke moving at the same speed as the source.
  • Normal
  • When using a mesh source,this option controls how much velocity smoke is given along the source's normal.

Initial Values

• Absolute Density
• Maximum density of smoke allowed within range of the source.
• Density
• Amount of smoke to emit at once.
• Temperature Difference
• Difference between the temperature of emitted smoke and the domain's ambient temperature.This setting's effect on smoke depends on the domain's Temperature Difference.
• Smoke Color
• Color of emitted smoke. When smoke of different colors are mixed they will blend together,eventually settling into a new combined color.

• Flame Rate
• Amount of "fuel" being burned per second. Larger values result in larger flames,smaller values result in smaller flames:

Example showing two fire sources.The object on the left has a Flame Rate of 5, while the one on the right has 0.3.

• Sampling: Subframes
• Number of subframes used to reduce gaps in emission of smoke from fast-moving sources.

Example showing two fast-moving sources.The object on the left uses 0 subframes, while the one on the right uses 6.

Smoke Flow Advanced

Reference

When using a mesh as the Flow Source, you can use these settings to control where onthe mesh smoke can be emitted from. These settings have no effect on outflow objects.

• Use Texture
• When enabled, use the specified texture to control where smoke is emitted.
• Vertex Group
• When set, use the specified Vertex Groupto control where smoke is emitted.

Example

These settings are useful for effects like this: