Scale

– Scale is another parameter involved in the Wavelet algorithm.

– As for all parameters in the Tab Noise you can tray different values without baking again the simulation, you only have to rebake the noise.

– If you input a zero Blender will set Time=0.0001 as you can see by clicking again on this field (same as for Scale)

– If you want Scale to produce different distribution of the noise, you do have to set Strength >0

– Note: As you can see I didn’t apply any denoiser to this simulation to better appreciate the noise added by this parameter.

– In this example I set Strength=1 so that changing the Scale value leads to some difference in the added noise. It seems that the bigger this value, the more complexity is added.

– “Greater values result in larger vortices (source: docs.blender.org)

Blender Smoke Noise Scale

CFL Number

– For now you can refer to the Fluids simulator CFL Number

– I’ll prepare some example in the future but it is not a priority as the Smoke and the Fire simulators share the sames principles.

Time

– Time is one of the parameters involved in the Wavelet algorithm.

– As for all parameters in the Tab Noise You can tray different values without baking again the simulation, you only have to rebake the noise.

– This value has an influence on where the noise field is evaluated. It can be used as a seed to give wavelet noise a slightly different look in two domains that are otherwise the same (source: docs.blender.org)

– If you input a zero Blender will set Time=0.0001 as you can see by clicking again on this field (same as for Scale)

– If you want Time to produce different distribution of the noise, you do have to set Strength >0

– In this first example I set Strength=0, for this reason the two videos are identical (and yes, I randomly compared some frames finding identical results):

– Note: As you can see I didn’t apply any denoiser to this simulation to better appreciate the noise added by this parameter.

– In the next videos I set Strength=1 so that changing the Time value leads to some difference in the added noise:

– Here a magnified detail:

Blender Smoke Noise Time
Blender Smoke Noise Time

Noise Method

– Noise Method is the method you can choose to add some procedural noise to your simulation.

– In older Blender versions this parameter was in the Hight Resolution Tab and you could choose between FFT or Wavelet.

– In 9.2 (stable) the only method available is Wavelet.

– You can control how the Wavelet is applied to your smoke/fire by setting some parameters in this tab.

– You can find some information about the code used by Blender (WAVELET_NOISE.h) here:

An Abstract and a Video

– and here:

A very interesting pdf

Blender Smoke Noise Method

Strength

– This parameter controls the strengths of the noise applied to a baked simulation.

– As for all parameters in the Tab Noise You can tray different values without baking again the simulation.

– The higher the Strength value the bigger the noise effect on your simulation.

– Note: As you can see I didn’t apply any denoiser to this simulation to better appreciate the noise added by this parameter.

Blender Smoke Upres Factor

Upres Factor

– As you know baking a simulation at different resolutions leads different behaviors.

– Upres Factor let you to ‘rise up’ the resolution of a simulation without changing its overall behavior.

– You can find Upres Factor in the Tab ‘Noise’ as this parameter is used when you want to add noise to your smoke-fire simulations.

– The bigger the Upres Factor the bigger the ‘added resolution’ :

Blender Smoke Upres Factor

Tab Noise

– This Tab let you add more details to the fire/smoke without changing the overall fluid motion.
– Upres Factor is the most important parameter as let you to ‘rise up’ the resolution of a simulation without changing its overall behavior.
– By the use of Strength Scale ant Time you can modify how the way the noise is applied.

Blender Smoke Fire Tab Noise

Temperature Maximum and Minimum

– The Minimum Temperature Ignition is the lowest temperature at which a combustible substance (when heated) takes fire in air and continues to burn (Temperature of Ignition).
– Maximum temperature is the highest temperature a flame can reach (for a given combustible).
– 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 Minimum (Temperature of Ignition):

– Third example changing only the Temperature Maximum:

Blender Smoke Flames Temperature Maximum Minimum Ignition