All Smoke Settings Explained in Eevee | Smoke Simulation Tutorial | Several Examples | Blender Eevee

if you have ever tried to create a smoke and blender ev you must have experienced many challenges i have also spent many such long hours to make my smoke work just the way i want in this tutorial we will discuss all the settings of smoke simulation in blender ev the possible challenges and their solutions so let us start with a new file we will use the default cube to simulate our smoke but you can also use any other object in place of this cube if you want to add a smoke effect for this object go to the object menu then quick effects and select quick smoke we can see that blender added a bounding box here later i will also show you how to add these effects manually so this bounding box is called the smoke domain you can see that a new object is now added in the outliner panel as the smoke domain this is the primary object in a smoke simulation but blender also made some changes to our original object or this cube it did not change its shape size or materials in the physics tab we can see that blender has enabled the fluid properties for our original cube object and also for the domain object that blender has added here the fluid properties are enabled before we discuss these properties in details let us first run this simulation and quickly see the smoke effect with the default settings you can see that the smoke is generated and it is rising up and filling the highlighted bounding box or the smoke domain you can enlarge this domain object or change its dimensions to get the smoke spread over a large area but a big size domain will take much longer time to simulate the domain has to be also quite bigger than our original object so one good option is to make the smoke object smaller and to bring down the scale of the entire scene otherwise you have to enlarge the domain object sufficiently for our scene let us resize our smoke object by 0.5 the characteristics of a smoke simulation is primarily governed by the properties of this domain object so let us look at its properties now in the fluid section of the physics tab we have this type field selected as domain there are three possible options here domain type flow type and the effector the domain type object defines the area or the volume within which the smoke will spread and exist no smoke will go outside this domain object the entire smoke will be confined and will circulate just within this volume for the smoke object we can see that it has the flow type selected so we will call it the flow object a flow object is the source of a smoke it is responsible to generate the smoke and the smoke spreads within the volume of the domain object so basically the area between the flow object or the source and the domain the area between them will be filled with the smoke blender only supports a rectangular domain object apart from the domain and the flow objects we have another type of object called an effector a factor is an external factor that creates some force like a wind or a turbulence it affects the smoke and blows it towards another direction or creates a cyclone effect but smoke will be visible only within this domain object so make it enough big if you also add an effector let us now look at the properties of the domain in the domain type we have gas because we are working with smoke then we have resolution division this defines how much details will be visible in the smoke texture with a lower number of divisions the smoke will look very ordinary while a higher value will result in a high quality smoke but a higher value will also mean higher time to generate the simulation so during the design phase you can use a lower value like 20. and in your final render you can go for a higher value say 64. but please also remember if you use a higher value the smoke will look better but the amount of smoke will be less a lower number of divisions will result in more visible smoke but the details will be missing i have found that a value of 40 to 50 is a good trade-off between these two essential factors in the smoke quality this time scale is less relevant for us because it controls the simulation speed or how fast the smoke develops this is primarily useful for still renders where you just need one frame with full of smoke say frame hundred so you want to quickly reach that state fast forwarding the actions by increasing the time scale factor here for a video animation just use the default value this cfl number works along with these time step minimum and maximum values together with this adaptive checkbox in a smoke simulation two things are going on one is your own animation where objects are moving at a specific frame rate decided by you along with that the smoke simulation is also going on at an internal frame rate decided by this cfl value these time step values determine how many simulation steps blender will generate internally to achieve the quality of the smoke you need if you have a fast moving smoke use a lower cfl number and also increase the maximum time step value it will result in a more physically accurate smoke with longer simulation time otherwise just go with the default values now border collisions by default when a smoke reaches the boundary of the domain box it disappears but if you enable the border collision for one or more sides here for example if we enable the bottom option once the smoke hits the bottom surface it will bounce back and will circulate within this domain volume for any other sides it will pass through the boundary walls and will disappear immediately we should always enable this adaptive domain option if enabled blender will dynamically calculate the domain volume ignoring those parts of the domain where there is hardly any smoke it saves the simulation time without any adverse impact on the simulation let us start the simulation and see it in effect the boundary box is changing its size as we proceed through the simulation as the smoke goes up blender is adapting to the increasing volume of the domain it results in a simulation at a faster speed next we have these three fields together they control the direction of movement and the velocity of the smoke a positive value in this buoyancy density means the smoke will be lighter than the atmosphere and it will go upward and a negative value means the smoke will fall down but buoyancy is not the only factor that affects the smoke we have this heat also that similarly determines whether the smoke is lighter or heavier than the atmosphere so it will be a combined effect of these two fields to see the effect of this buoyancy density we have to first make this heat factor is zero so that it does not affect the smoke now enter a negative value to the buoyancy say minus two and go to frame number one and start the simulation to see its effect let us change the viewing angle slightly so that we can see the actions better you can see here that the smoke is falling down instead of going up and it is resting on the floor we have also enabled the bottom surface for the border collision so it gives a nice effect of cold air or heavy gases or maybe dusty air that spread on the ground you can make a laboratory scene with this let us now change back these fields to their default values this will be one and this heat field should generally also be one this vorticity field creates random turbulence within the smoke by default the smoke is uniform in all directions with vorticity you will see lots of small spins and swirls within the smoke that make it more beautiful let us change it to 0.25 if you now go to the first frame and run the simulation again you will see that the smoke is not only going upward but some portions are also spreading in random other directions and the texture of the smoke is also quite improved like a high quality smoke along with vorticity another beautiful option is this dissolve option that makes the smoke look very real if you enable the dissolve option the smoke will dissipate or disappear slowly you can expand this section and you can enter a time value here after which the smoke will dissipate let us enter 20. blender will continue to generate new smoke and the old smoke will disappear after the time interval so go to frame one and start the simulation once more you will now see that the smoke is not filling the entire domain at all it is disappearing before it can reach the boundaries this looks much more real more beautiful and this also takes away the boundary problems as there is no sudden fallout then we have the noise option let us select this and expand the section it gives us an option to add more finer details to the smoke further increasing its quality currently in the noise method we only have wavelet you can play with these values to have a different noise settings that will apply on the smoke let us go to the first frame and run the simulation again soon we discover that no smoke is visible anymore in our scene this happens at times when despite all your efforts the smoke just does not come back and you may feel helpless but do not worry in the fluid properties for the domain object you can see a section for cache with a path to the cache files open this location the smoke simulation data is stored in these folders go one level up this is the cache folder we have to delete this entire folder structure to clean the smoke data already saved this solves our problem now go to the first frame and run the simulation again now the smoke will generate without any problem the smoke is also little better as we have enabled the noise option this time finally we have created a fantastic smoke that is lighter than the air surrounding it here we have the smoke start and end frame numbers which by default matches with your scene start and end frames but you can define a different frame range where the smoke simulation should take place usually you do not have a smoke for the entire scene so mention the start frame and the end frame numbers when you need the smoke the other fields are less important and you can go with the default settings for them let us now look at the smoke settings for our flow object which is this cube it generates the smoke and it controls a few properties of the smoke the flow type is of course smoke the flow behavior has two options inflow and outflow outflow is used where the smoke will be sucked up instead of generating it so the smoke will disappear if we have an outflow type of flow object it is less relevant here it is more applicable for liquid fluids like in a bathtub where you have an inlet and an outlet but for smoke we hardly use an outlet so it will be always an inflow only let us look at sampling sub steps the smoke is generated at a frequent interval if the flow object is moving very fast like a rocket exhaust you should increase this value to say three or four so that there is less amount of gaps in between smoke formations and the smoke does not look intermittent or disjoint now this smoke color is supposed to define the color of the smoke but it does not really work in that way this smoke and the density need additional adjustments in the smoke material without which it does not come out as we expect i have created another tutorial on how to get a colorful smoke or a thick smoke the link is in the video description you may want to check out finally this initial temperatures defines the temperature difference between the smoke and the atmosphere when the smoke is generated a positive value will make the smoke lighter and it will go up and a negative temperature difference will make the smoke fall down but remember that this temperature difference works in combination with the heat factor for the smoke domain which we have defined here this is little tricky actually there is a relation between this heat factor of the domain object and the temperature value of the flow object here let us look at this chart to understand their relationship better you can imagine these two values to be multiplied to get the final result if the multiplication gives us a positive number then the smoke will go up and if it is a negative number the smoke will fall down so for a normal smoke you can leave the temperature just as one next we have flow source this may not be very important usually we don't change it but we have an option for particle system here it can create very accurate and fine smoke however this will take much longer time to simulate and may not be suitable for a quick smoke scene under mesh option if we enable this planar checkbox the smoke will generate only from the surface area of the flow object not from its entire volume it does not make much difference except that the amount of smoke may change a bit this initial velocity can be very important at times for example if the smoke is coming out of a helicopter which is on fire we should enable this initial velocity option so that the smoke starts with the same velocity as that of the flow object and in case of a rocket exhaust you can manually alter this velocity such that the smoke comes out with force in the opposite direction this texture field can be used to apply any particular design or pattern to your smoke so we have discussed almost all the smoke settings and properties if you want you can even hide the flow object in the viewport or in the render it won't be visible in the scene only the smoke will be visible but if you hide the domain the smoke will disappear so the domain is basically same as the smoke the flow object only controls how the smoke is generated now in addition to this cube object we can have more flow objects also within a domain and you can use multiple such domain objects if the flow objects are far apart from each other let us add another flow object just add any mesh it is too big for this domain so scale it down by point five we will also move it up a little bit so that the two flow objects are placed at a distance within the same domain now in order to turn this sphere into a flow object in the physics tab enable the fluid option by clicking on this in the type field select the flow type among the other settings the flow type will be smoke only but change the flow behavior to inflow that's it we got another source for the smoke let us have this cube generate a lighter smoke that will go up and the sphere will generate a cold or heavier smoke let us change the initial temperature to minus one for the sphere object it will create a cold smoke that will go down but remember this temperature is not the only factor that control the smoke velocity we have to also go to the domain properties and verify the heat factor here it should have a positive value and we need to also change the buoyancy density to zero so that it does not affect our smoke only the heat factor affects it so for the cube flow object we have set a positive temperature and for the sphere we have set a negative value now go to the first frame and start the simulation to see its effect you can see how the two smokes are behaving differently one going up and the other falling down ultimately they mix up and exchange the heat as per standard physics they are sharing the same domain so the smoke quality is also same for both only the behavior is different this has been a long tutorial but i really wanted to cover each factor in details i want to tell you about two more things which are important sometimes you will find that the smoke is not generating whatever you do whatever you change it just does not work it seems in such a case you can do few things first check the temperature settings that you have for the flow object here and then in the domain object cross verify the density and the heat factor these three together define the smoke behavior which way it will go please remember that a high value in the vorticity field can suppress everything else now if it still does not work sometimes the smoke may not be visible your recent changes are not taking effect you can try to delete this cache as i have described earlier just remove this entire folder structure from here or from your system's file manager it will reset the smoke data if it still does not work you can try to change the volume type from openvdb to uni cache and then change it back to openvdb again it may work in some cases and the third thing that you can try is go to the render properties tab and change the render engine to cycles once and again change it back to ev this is weird i know but i have seen this solve some problems at times another challenge that you may face is the smoke might look good here but if you go to the rendered view mode you may not find the smoke enough good at all it is very faint here in the solid view mode it was quite dense but it is very thin like this in the render output to fix this we have to change the light so go to the light tab and change the light to a sun then reduce the strength to something like three now you can see a good smoke which was visible in the solid view mode it will now render exactly like this in the next tutorial we will discuss how to set up a material for this smoke and create a colorful smoke or a thick black smoke i hope you like this tutorial thanks for watching and don't forget to subscribe to this channel

Channel: 5 Minutes Blender

Views: 62,228

Keywords: Blender 3.2, Blender 3.1, Blender 3.0, Blender Tutorial, How to use blender, Blender basics, Blender tutorial for beginners

Id: uT127TSmBwU

Length: 18min 3sec (1083 seconds)

Published: Fri Feb 26 2021