Temperature Ignition and Maximum

– Temperature Ignition is the lowest temperature at which a combustible substance (when heated) takes fire in air and continues to burn.
– Maximum temperature is the highest temperature a flame can reach.
– If you know these two parameters for a specific substance Blender let you set them in this tab.
– The values are expressed in Kelvin/1000
– Converting Celsius (°C) TO Kelvin (K) is easy: T(K) = T(°C) + 273,15

– In this example I rendered the flames produced by two different substances: Butane (Temperature Ignition: 678,15K ; Maximum temperature: 2243K) and Oxyhydrogen (Temperature Ignition: 843,15K ; Maximum temperature: 3073,15K)
– You have to divide all values by 1000 so that the value you have to insert are:
– Butane: Temperature Ignition: 0.67815 ; Maximum: 2,243
– Oxyhydrogen: Temperature Ignition: 0.84315 ; Maximum: 3,07315

– Remember: in these videos I only want to explain what these parameters mean, these simulations does not pretend to be ‘realistic’. First of all I usually set a reduced Time Scale so that you can appreciate better the evolution of the system, and second I focalize on a specific parameter while a good simulation needs to adjust lot of parameters, materials, lights etc…

– First example, Butane and Oxyhydrogen:

– Does these two parameters make sense if you are rendering a flame without using specific values for specific substances? Blender let you use, and not only in fire simulation, values that lead to not realistic phisical simulations, and I think this makes Blender incredible as it let your fantasy unwind and create!

– Second example changing only the Temperature Ignition:

– Third example changing only the Maximum temperature:

Blender Smoke Flames Temperature Ignition

Initial Velocity – Normal

– When using a mesh source, this option controls how much velocity smoke is given along the source’s normal.

Initial Velocity – Source

– Multiplier for inherited velocity. A value of 1 will emit smoke moving at the same speed as the source.
– Note: this is only the INITIAL VELOCITY! After the emission both smoke and fire follow their usual behavior.

– In this video the effect for Source = -2.0 is more evident during the ascending motion (the resultant Initial Velocity vector is opposite to the ascending flow).

– Another example: I set Temperature Difference = 0 so that the smoke does not move away from its poit of origin unless it has some velocity.
– During the firsts 50 frames the flow emitter doesn’t move, all fire and smoke emitted don’t move from their origin.
– For Initial Velocity = 0 you obtain a very weird effect, of course as both smoke and fire are emitted with no velocity, they don’t move from their points of emission.

Blender Smoke Initial Velocity Source

Mesh – Volume

– Amount of smoke to emit inside the emitter mesh.

– 0 = 0% , 1 = 100%

– Attention: may have unpredictable results if your mesh is non-manifold.

– It isn’t so easy to show the smoke inside an objec, so I tried to make a two videos showing a sphere with 0% and 100% of smoke inside viewed from above. You will also notice a pattern generated by the voxels.

– You can see (expecially at the very beginning of the video) much more smoke near the borders of the sphere in the case of Volume = 0 and a more uniform distribution in the case of Volume = 100%.

[download .blend]

– The same videos from another point of view:

[download .blend]

Size

– When this setting is enabled, it allows the Size setting to define the 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.

Flow Source

– Defines the method used to emit smoke and fire.

Mesh: Create smoke/fire directly from the object’s mesh. With this option selected there are two additional settings: Surface and Volume.

Particle System: Create smoke/fire from a particle system (type Emitter) on the flow object. With this option selected, there is a box to select a particle system and one additional Tab: Particle Size.

Blender Smoke Source Mesh Particle System

Flow Type

Fire: Emit only fire. Note that the domain will automatically create some smoke unless you set to zero the parameter ‘Smoke’ in Smoke Flames Tab (see Smoke)

Smoke: Emit only smoke.

Fire + Smoke: Emit both fire and smoke.

Outflow: Remove smoke and fire. (the shape of the outflow will use the object’s bounding box).

– Note the difference between an Outflow and an Obstacle (Collider) :

Blender Smoke Flow Type