How to Render Fire in Cycles

g'day and welcome to another blender guru tutorial I'm Andrew price and in this video you're going to learn how to make the elusive fire something that a lot of you have been asking very excited about this tutorial cuz it's revisiting one that I did many years ago which was when you had to use the blender internal engine smoke was pretty and but we've come a long way now cycles now supports fire and smoke rendering the smoke simulate has got a whole bunch of improvements added and so you can get some really cool-looking results so I've spent the last couple of days going through the smoke simulator and like tweaking every little setting trying to figure out how it all works and how to get the best looking fire that you can so I'm going to be sharing with you everything that I learnt then we're going to be making a roaring fire that you can see right here the scene around it that you can see the forest scene with the the grassy meadows I'm going to cover that in the next tutorial we're going to be using something called the grass essentials pack to create that beautiful looking grass across the floor there but for this tutorial we're going to focus entirely on the fire so this is the scene this is what we are going to be making so by the end of this video you'll have this roaring little Beauty this little cool little campfire so will be of course you'll be discovering what all of these crazy settings in here mean it looks very intimidating but it's pretty easy once you figure it out we'll also be adding in some embers so getting a particle system to interact with the smoke simulator which is really cool something that took me ages to figure out and yeah basically just add tweaking all the little things in order to get some nice realistic looking fire and rendering it in in cycles so without further ado let's go ahead and open up a new scene in blender so what we're going to do is we're going to start by creating a really super basic smoke simulation and getting it rendering in cycles so you guys can get that result finished and then we're going to start tweaking it to make it look more and more like realistic fire with this default cube here we're going to go ahead and delete that and we're going to replace it with a circle and this circle is going to become the emitter like the actual flame for the fire so it needs to have a face important so in the tool bar just enable n-gon now it's got a face that's good and now this is a really cool part creating smoke you know youngster going blender used to be a nightmare were so many things to do now you can do this object quick effects quick smoke now if you hit alt a look at this bomb smoke already so yeah this was added by a Micah a developer and get two years ago he realized you know how many settings had to be you know change before you get something basic like smoke and so he's enabled yeah like this quick smoke effect and what that's done is it's added in you know all the things here for basic smoke it's made this circle the flame emitter will be a smoke emitter at the moment and as well as that if you go to the node editor look at this he's actually already added in the basic node setup in order to render smoke so if you render right now you might not see anything and the reason for that is that currently as of 2.73 January 2015 you can't render smoke on your GPU unfortunately you can only render it on your CPU so if you can't see anything switch to CPU but if you can try and stick the GPU in the future I'm sure it will change anyways so there we go we've got some basic smoke setup but it's not a fire is it not even close it's very thick and black so what we want to do is go back to our little box over here and select this circle so this is the emitter the smoking metal now if you go to the effects settings over here you can see that you've got underneath flow source oh so it flow type you've got our what says smoke now that used to be the only one like in for the smoke simulator you could only have smoke and then you had to like do a lot of tweaking in the materi in order to make it fire now you've actually got something there called fire which you can click now it's kind of confusing because you'll also be you know tempted to click on fire and smoke because you're thinking like I want fire but I want that fight to emit smoke right so you're thinking fire and smoke is the one I want but actually it's it's misleading what that's actually going to do if you click fire and smoke it's going to create kind of a fire emitter and then a smoky meta so it's doing both at the same time which is weird fire if you just select fire it will actually make fire as well as smoke so I don't know why I mean yeah you should always just select fire because you only want fire all right now if we reanimate that look at that you can see we have some fire tada a little mushroom cloud going on to be really great for like a nuke tutorial or something okay so fires in the in the 3d viewport if we hit render ah no fire barbar what a shame so why is there no fire the reason for that is that our this quick effects quick smoke it's given us a very basic smoke node set up just for smoke if we want to have fire in there we have to do some tweaking and it's actually fairly easy to do you know once you get the hang of it it can be a little bit daunting at first but yeah I'm here to walk you through it so what we've got in here is this is the smoke and you can see we've got these two nodes here called attribute nodes and they've got names one says color one says density so somewhere in the smoke voxel data wherever it is I mean it's basically magic to me I don't know where it stores it all it's an occasion it's box whatever but somewhere in there is something called density and that's what this attribute node here is referencing when it says a density right and so you can then use that data what we want to do is add another attribute node and we want this attribute node to reference flame now it needs to say flame exactly exactly as I've typed it there flame and when you do that it's now going to reference the part of that voxel data the smoke simulation which is the flame okay so it has to be typed out exactly like that all right so once we've done that we can now define what the flame is going to look like so we want to add is a color ramp note one of the most popular heavily use nodes I use it all the time love it you can use it for so many things the color ramp node if we connect the output of this factor from this attribute node into the color ramp input what this is going to do is allow us to yeah change the color of the real fire so for reference this is what real fire looks like I can't by the way provide this video file for you because it's a is a paid stock footage they had to pay for so I can't provide it but you can see it here okay this is what it looks like so at the brightest point of the flame that's when it is white it then as it's you know decreasing and heat a little bit it becomes a bright white yellow color then it becomes an orange color and then add towards like the edges it becomes like this reddish color this reddish tint which is why when you're all sitting around the fire everyone has this sort of reddish glow to everything right so that's what you want to put into the color ramp node so the in on this color map node here this part here on the right hand side that is what is going to be the color of the hottest part of the fire which at its current state white is exactly what we want and at the lowest part over here the black part the left side that is what the fire is going to be at its coldest point so that's actually correct as well so what we want to do is in between these two is we want to add in a few different colors so first of all right near the white one because it's only white for a tiny little brief point before it's it's yellow okay so we want to add in here at this point here we want to make this a whoops a bright whitish yellow color like that then over here we want to add in a orangey red color like that and then I want to drag this black point to this anchor right up close to this orange point and the reason that I'm doing that is that I've noticed from looking at reference footage is that the fire is there for like an instant and then disappears like it towards the edge like once it's cooled off that flame like disappears in an instant like the top of that flame right there I watch it go boom just poof just vanishes so if you had this dragged out over here what that's going to do is it's kind of going to fade out so your fire will have this sort of like flowy soft look to it it doesn't look real you want it to look like aggressive chunky like it's there and then it's gone you know the fire is quick so that's what bringing this black value in will do like next to the orange ones like there's no grace period it's there and then it's gone instantly all right so that's what you can do now you can tweak these later I'm not showing you like the exact you know the hex dial you don't have to copy that like it's just getting the basics right the white the yellow the orange and and then you just want to play with that and just to look at reference video and just try and get it as close as you can all right but this is this is all you need in order to get some fire going then what we want to do is we have to add this to the rest of the node setup and because this is a flame it's actually emitting light yeah everyone knows that the olden days you know they walked around with a candle and a lantern why because the emitting light that was their light source right so it's we wanted to emit light so actually in the rest of the scene everything that's around the flame actually has light on it so the way you do that is by adding in an emission shader node so we drag the color output from its color node into the color input of the emission and then we take the output of this emission shader and look at that we have an empty add shade a node there where it's conveniently there's a bottom input which is left open for us so it's almost like they knew they knew that we were going to have to add in the flame here so they wanted to give us some you know room to do that already set up to go so that's what we need to do now one final thing is the strength of the flame we can actually take the data from the flame and tell it the hot pods we want to be brighter than the cold apart like a real flame so the way we do that is we take the factory output and we put that into the strength input of that emission shader but actually what that will do is that'll just give us like sort of a bland like low light looking flame and we can't really adjust that what we can do though is if we add in a math node we can take the output from this factor input put that into the top input of the math node and then if we set this to there it is multiplied we can multiply the original value to be whatever we want so if we take this output here and then put that into the strength in put this value here now becomes the strength of the fire like the brightness of the fire so if we set this to 20 that's going to give us like some really nice-looking fire 20 I found works well for most cases some instances if you want it to like light up things even more and it's like a smaller sort of flame 40 anywhere from 20 to 40 any of those values is going to work for you just like I said tweak it for your scene like these values that I'm giving you here it's not set in mud when you're watching a tutorial you might think like it has to be exact but like adjust it if it looks a little funny in your scene feel free to adjust things so these are just the base ones 20 to 40 anything around there is going to look great so now that I've said all that let's get this camera position in front and center to our flame here and I'm just going to change this resolution size so that it's square not widescreen good and now let's give this save before we try and render it and let me just adjust the tile size because I'm rendering on CPU unfortunately I have to have to use small tiles but look at that we now have the flame rendering so it's no longer just that dark smoke we have the flame actually appearing in the render so that's it that's I mean that's that's that's the end of that you know it's not the energy tone because it looks horrible at the moment but this is you know if you wanted to you know continue on here just want to learn how to render the fire that's how it's done you set up those things you're good to go now what we're going to do is make this fire not look so crappy because at the moment that looks horrible that looks like I mean I don't know I don't know what it looks like a marshmallow that's on fire it's really it's the worst so we're going to be tweaking some of these smoke values here we're going to go through here and we're also going to be adjusting this emitter I'm going to show you a little trick in order to make that look more realistic so yeah let's go ahead and do that so if you've never used the smoke simulation before basically the one value you're always going to be changing is the division's and that's as it says the resolution of the smoke so if we increase this to 64 what you'll see is that the smoke looks a lot tighter there's a lot more detail in it but you can also see it's taking a lot longer to to bake and that's really the perfect description of the the resolution setting it's yeah nicer but just takes longer so for the most part like whilst you're testing out settings just keep it at 32 you can gauge the basic behavior of the smoke just keeping it at 32 there's no problem with that so we'll leave it at that for now my final one that I did by the way I used 128 just fairly low and it still looks fine to five six you might want to go that I once went to 512 but that's just getting crazy and that's when really want to take a week off from your computer so you can do the baking anyways so leaving in the 32 now we'll come back to smoke flames because the first thing I want to do is I want to turn on smoke adaptive domain so what does that do you might be asking when I hit alt a there you can see that there is now like a cube within a cube you can see there's this cube there and there's the actual cube so this actual cube that's the domain which is like the the box in which the smoke is going to be calculated now it used to be in blender like you have to try and make that box as small as physically possible because the bigger the box is the more it would have to bake in sight so you know the longer the baked times are by having smoke adaptive domain what it's doing is it's automatically figuring out the correct size of that domain cube so you don't have to figure it out so you can see here like as the smoke is small the box itself is small and then as it gets bigger the size of this domain gets bigger and that's the idea of it so by default I mean I just think this should always be on I can't really imagine a situation where you'd want it off just leave it always on and you're always going to have faster bake time so just leave that on the next one is the smoke high resolution settings so what this does is if I pay this you'll automatically see the result it looks a lot more detailed so like the description says it's giving us a higher resolution look to the smoke how it's actually working is is it's taking this division you know the resolution of your smoke it's treating that kind of like the blob or the cage of the smoke and then this high resolution setting that is then adding like fractal noise to that smoke tip like on the outside like a cage so that it looks more detailed on the outside so the main sort of behavior if the smoke and everything that's changed in the division's there but there's are this high resolution divisions that's going to give you the stuff that's going to make it look awesome so any you know final baked that you do you should definitely be using high resolution you know that the most I've probably ever used three let's probably like max and that's overkill generally two and even one I think for my final bake that I did for my animation was actually just yeah it was Division one it'll increase the bake times crazy just going from one to two even yeah at one its increased it a lot so keep that in mind but we can leave it at one and it's still you know it's baking fairly quickly right now which is good the other one that you want to change in this area is the Moi's method now when you click the noise method you can see you've got two values here FFT and wavelet both of which are equally as confusing and pointless to artists because that says nothing to us we've got no idea what either of those mean there's no clues it's a guessing game 50 more wavelet now I'm sure like way back you know ten years ago whoever developed the original algorithm maybe his initials were FFT so he called it that or I don't know where these names come from but they're not helpful to artists and so you kind of have to guess well I did some tests myself using the the reference video and went that reference video go yeah I did some tests with the reference video and I had a look at you know the different ones and I found that personally wavelet gives you the closest looking you know fractal noise like the detail on the outside of the fire which matches real reference fire so you can leave it at wavelet other people suggest FFT in fact even my first tutorial I suggested that I've changed its its wavelet that's the one that's what I think produces superior results the strength of the noise that's important you want to go high because from basically just as a rule the smoke that is you know generated by the smoke simulator it looks too smooth it looks like I don't like a blobby fluid than an actual you know smoke so you want to increase this noise that's on the outside to be higher resolution and like like more noise so that it looks more like real fire because real fire is just crazy it's all sorts of stuff going on as you just saw in the video so yeah so increase that to 5 and you can see you've already got like really like a lot better looking fine just by enabling high resolution and strength of 5 the rest of it the case this is important when you do your final bake you're going to click that bake button right there and then it's going to go through and bake everything what you want to do though is you want to first of all make sure that you have actually saved your blend file somewhere this is important so if you don't do that you can't do this next part then once you've done that you want to give this a name any name doesn't really matter because I found if you don't give this a name sometimes you'll close blender and then you'll reopen the old file and all your cash is gone like I don't know where it went it just vanished into the blender sphere or whatever it's gone and and that's a real shame so you want to make sure that it's saved so calling it something I think saves it into a separate folder in fact let me check this I will probably have to bake it actually first but you do the baking let me just check this now on my separate monitor here you guys can't see what's going on I don't want to show you the contents in my harddrive but I do want to be able to tell you if this is actually correct tutorial okay should hmm blend cage okay so it's putting it in a blender way giving it a name just make sure it doesn't like vanish all right which is pretty important so anyways um now the end frame of your bake that's important if you just leave it at the default value of 250 that's an animation that's ten seconds long which is way longer than what you need to be able to tell if the smoke is looking good right so just leave it at a baked of 100 if you're gonna do a longer animation obviously adjust that because basically 25 frames per second 250 frames that's 10 seconds so change that depending on how long you want your animation 100 frames is going to give us a 4 second animation alright has a little math class for this tutorial alright now for the smoke flame in Doom this is the settings that can kind of matter a lot first of all I'll just address something here the emitter this circle here it's almost I don't know it's like 20% under like the stuff underneath here we don't need that like the smoke is going in this direction so this box here should be moved upwards so that we're making full use of the domain the domain size you want to have it so that it's like resting like right on its edge or else you'll have problems but you know that distance from it is a little bit better than what it was before so now that it has more room for the smoke to rise okay so now that I've done that let's go back to what I was just talking about smoke flames alright so you've got something here that says reaction speed the speed of the burning reaction and you think like oh that must change like how fast the flames move wrong actually what this does is it it changes how much of the smoke is actually going to be fire this name makes absolutely no sense to me I don't know why it's called speed a reaction speed it should be called flame height that would make more sense for artists but it is what it is I'm sure I don't know scientifically the speed of reaction is why it's given that value anyways so the lower you set this to like just can make a mental note of how this fire looks like they're like the percentage of how that looks there and that's at 0.75 if we set this to 0.3 watch this now the flame will become bigger it will eat up more of the actual smoke so more of that smoke is now fire like the actual like the behavior of it has not changed at all just the parts that are smoke and the parts that are fire they've altered their percentage like their ratio if that makes sense so lowering that will increase the size of your flames now this looks crazy big at the moment but once we increase the divisions and also do the next step which is really important adding in the stuff that makes the flame you need to actually look like a real fire instead of like a blowtorch like it does at the moment this is going to look a lot more you know sizable like the right size now the other one you want to change is the smoke amount the amount of smoke which is generated by the burning fuel essentially the smoke that comes with the fire so if we increase that from 1 to 4 we will get four times the amount of smoke with that fire and I found personally the more fire is is going to help you especially for a nighttime camping sort of scene because you want to be able to have you know in the render you won't be able to see some smoke above it and leaving it at one especially at higher resolution values the smoke is sort of wispy and it's barely there so you want to crank that up so we get some more you know plumes of smoke pumping through that at the moment it looks more like a bit of a an oil fire some sort of rig caught on fire but it'll look better later on the other one you can change although it's optional you can change the maximum temperature the flames I increase it to 3 so that you know parts of the flame can be a little bit hotter that makes minimal difference vorticity as well surprisingly doesn't make that much difference here but you can increase it slightly if you want however here underneath behavior of the smoke increase that as high as you can go for and that's going to make the flame and the fire just look a lot more choppy like it's like the the turbulence of it is going to be increased because that's really that's often what we're battling when it comes to making the smoke and fire in blender it's just trying to make it look like look make it look as choppy as real fire which is this sort of chaotic you know scrambled mass of everything but you know computers being perfect it often is just too smooth and lovely which is not what we want we want it to look real so just to recap all the values I've changed vorticity set that to four smoke flames reduce it to 0.3 to give us bigger flames smoke increase it to four so we get four times the amount of smoke with it you can increase the temperature to three if you want and the vorticity to one if you want it's not going to change that much but it'll give you a little bit you know more interesting flames debatable and then the smoke adaptive domain that should be by like default it should be on already I don't know why it's off but just leave that on and then the smoke high-resolution division's one and then leave the noise method as wavelet not FFT and the strength set that to five so yeah it's coming along great great so far but let's talk about this problem that we have with our emitter it looks like a blowtorch or you know if we were to sort of you know I can position the camera so we're looking at it how do you make it look sideways I want to look like a left to right if this was like sideways this would be great at the back of a like f1 jet you know real fires not like this like if you've got a you know I can't fight thing like that unless it's filled you know to the brim with petrol and it's even then it wouldn't be the same like it is always flickering RealFlight fire is like hot in a place and then it's cold and then it's hot and then it's cold and like it's like patchy so it flickers over the surface and that's what gives you this realistic fire like this like this wood here it's not just one piece of wood that's constantly burning parts of it are burning you know and like this sap of that will release some energy and then that part will blow and then that part will be cool but then it will get hotter and then that part will go and that's what gives you this little choppy you know tiny little flames and that was the part that I was always annoyed with with you know with smoke and fire and blend it was like it's just a constant big chunky flame and that's why it looks so fake so and I learnt this from another youtuber and I'm sure maybe he learnt it from somebody else as well but this is how you can do it like really easy really cool underneath if you select your emitter which is this circle check use texture and then from here in the drop down you're going to have to select a texture and by default that's just one they're called text might as well use it with that texture we want to define how that texture looks so this is the tags that's going to define which parts of this plane here is going to be the parts that's going to emit the fire so in the texture panel let's go and select from the drop-down the name of that texture which is text and then the type we can select what type of texture it is so we're going to use clouds of course because that's what we always use with the texture is like the most used texture I reckon like if you go through every blend file ever made 95% of procedural textures got to be clouds it is so useful um anyways we're going to change the size of this like the size of this noise so that it is like tiny little bits like if you make this bigger then you're going to have like big wafting parts coming off the flame which can be good if you want to make the look of like I don't know controlled burn with fuel or something like that but we want it to look like flickering wood you know so we're going to go for a smaller noise size we also want to increase the contrast it is - - so we've got some real coal part and some real hot parts we just sort of like amplifying it's a you know the influence of that and reducing the brightness as well so now it's sort of 50/50 like part of it will be flame part of it will be a you know what I mean pipe pipe will be flame part of it will not be flame gosh hmm so now let's have a look at this Oh so it's no longer one solid flame it's an actual fire like one simple little change is all it takes to make it start looking like real fire awesome right that's just it infinitely like automatically looks way better but trouble is though is that now we have kind of the same problem before like there's parts of it which are constantly burning right it's not really flickering it looks better because it's you know choppy now it's got some different heights to it but it's not flickering so what we want to do is we actually want to animate that texture so that the parts that are hot and cold they change constantly okay so this is how you do it we let's load up a timeline if you haven't already got that up set the end frame of our animation to 100 because that's what we're going to bake to as well go to frame 1 and this is how this is how you normally add a keyframe in blender as well for anything or change the color or something in or change the movement you use I right you know set a keyframe for whatever you can do that for values a lot of people don't know you can do that but you can hover over this offset value there that's like the position of the texture in its texture space right if you hit I over that that value become it goes yellow meaning there's now a keyframe so now if we go to the end of our animation frame 100 let's increase this offset to for the high you set that to the more it's going to change the more it's going to flicker around so I'm using yeah offset for for 100 frame animation if you want to go for sort of slower more wafting burns you can use a lower value you get the point so this just controls how much flickering you want so again hover over it and hit I see it should be yellow on both the start and the end frame of your animation so 0 to 4 in 100 frames let's give this a little render now and see how this guy looks and look at that you can see even though it's low resolution it's flickering so there's parts of it there's parts of it that are on and then it's off then it's on then it's off and we're now getting some really awesome looking fire it's actually starting to look like real fire should which is exciting right it's cool so um you know what I'm going to do you know what I'm going to do I'm going to bake this thing let's go 264 frame a 64 resolution which is sort of half of what the final one would be and let's give this a bake so we've named the case we've you know put in 100 frames for the baking let's go ahead hit bake I'll pause my recording whilst it's doing that and then we'll see how it looks alright well I just had lunch in that time gap there which is unnecessary I mean it really only took a few minutes to bake but uh but check it out look at this that looks like actual fire like something is burning look at it it's it's it's got all the right flames in the right places the smokes it looks great looks like actual smoke and if you actually render it let's give this a little render here ah it actually renders the flames like it should the smoke like it should and is pretty much ready to go so you might be thinking like alright print done fire is completed but you'd be wrong or you'd be missing out on on an extra step that could make it look even cooler so looking at our reference fire let me do the school teacher thing what is missing from our fire that this fire has other than the wood of course ah alright it's embers all right I'll spoil the surprise we're embers those little tiny burning little particles that I'm assuming it's it's wood off the actual logs and stuff like little tiny flecks that catch a light and they get caught in the heat and they fly through the air that's what we're missing and for the longest time that used to be really hard to make in in blender because you would have to fake it using particles and then try and match the particle speed to match the smoke and it never looked right it always looked like because it has to be affected by the heat of it like these embers like no single one of them burns exactly the same as the one before like they're all just some of them are drifting ones that get caught into the main thermals they go really fast you know so it's important that it looks right and thankfully there was a feature in blender which was added a couple of years ago breaking news right that allows you to to have the smoke system effect other objects such as particles and so I was really psyched to try this out and then I added in the particles and I waited and nothing happened and I went online to try and find out how to do this this feature that was added because I figured everybody be talking about it and there was almost no help nobody was explaining it so I'm going to do it now see so it's out there an official documentation so first things first adding the particles the particles have to be emitted from the flame here so just simply add in a particle system right here and if you just you know animate that you just have them dropping out of the bottom there like that which is not ideal and you can see that obviously they're not being affected by the smoke at all I had hoped that when you just you know add them that it would just work magically will just figure out that it's in a smoke thing and just up it goes but it doesn't what you need to do in order to have the smoke effect other things is you need to add in forcefield smoke flow it's got a little smoking pipe next to it appropriate so you add in this object which is this empty and I don't think it matters where you place this in your scene actually but it might it needs to be on the same layer as as your smoke domain and everything else but provided it is there once you do is you go to the physics panel and then underneath the main object you need to select the smoke domain which is yet this guy right here called smoke domain so that one's really hard so you just select that and then watch this there's still dropping out at the bottom because they have a lot of gravity on them so let's take this particle system down a peg by dropping the gravity okay so now when we do that watch this well a and it's getting caught up in the smoke now one thing you want to check is that your particles are moving at the same speed as the smoke because here I have it I think that the smoke is moving a faster than the particles so what I'm going to do is increase the strength of this smoke flow to five and you can see when you do that that this now that they're moving a lot faster now and it looks a lot cool as well so that's basically it I mean you don't have to rebake the smoke or anything like that it'll basically just figure itself out and up and away it goes I mean it really is pretty cool actually so we've got that we've got the embers now behaving exactly the way they should now we need to get them to show up in the render because at the moment this is just you know it's dots on a screen which we able to view in the viewport but four cycles to render it it has to be like a physical tangible thing that it can render and this is just a point point data right that's how I understand it so what we need to do is add in an object which is going to become each one of those particles going to render each of them so we're going to use a UV sphere and these are going to be tiny like tiny little dots so we want this sphere to be really low poly so I'm going to use let's try five segments four rings yeah four rings basically super low poly like that just enough that it's going to actually be like rendered as a little dot on the screen and then once we've got that just move it out of frame of the camera but just so that you can access it and I don't know hit it easily once we've done that then select the particle system again and then down here underneath render select object and then just select the sphere and there you go so these are now the individual little spheres they're way too big at the moment so let's just turn down the size 2.02 is still too big but just so that we can see it in the next step we'll just leave it at that size for now now this will the default back basically whatever material that you give this that's the material that these particles are going to adhere to so if you want to add any material to these embers you have to do it to this sphere some of you I'm sure in all this but I'm just explaining it for those who don't so we need to give it an a new material to this sphere and this material is actually a little bit advanced like it's obviously you know embers are bright so we can figure out you know without too much stress that yeah it should be any mission shader that's a bit of a no-brainer because it's lighting up right but the color of it and the brightness of it that is really important and that is something like if we have a look at our reference photo here I don't know if you can see it too well because they're not that obvious but as the pot as the embers move like the more they move the brighter they are it's like a shooting star when it's like it's moving and then it's I don't know if the shooting star analogy works but the more it moves the brighter it is and it has a different color so as its brighter it's like white and yellow a color like that and then as its slowing down like it's getting less air so it's sort of starving itself like you know when you blow on coals and it brightens like that and then it sort of goes down that's what these embers are doing so the more they move the brighter they should be the whiter they should be and then as they slow down they should be a reddish orange color and they should fade away so that is what we need to do in this material known set up here and this is where a lot of people will just give up because it just sounds like it's too much work but it's really cool once you get it set up and I'll show you how to do it it's not too much work I shouldn't have said that I'll put people off so what you want to do is you want to add in something here called the particle info node this particle info node will allow you to take certain things like the age of the particle its lifetime its location a whole bunch of different things and make it tweak the material according to it the particles behavior which is exactly what we want to do so we want to use this velocity output to control the color and the brightness of it so what we're going to do is add in a color ramp node just like we did for the flame and we're going to define what's going to what it's going to look like when it's bright and what it's going to look like when it's slowing down when it's sort of dying away so the left-hand side this is when it's dying away and we're going to make this an orange color like that and when it's alive and bright it is a hot white color like that now what we want to use is the velocity now if we were to plug this straight into there that is not going to work it's just because you can see the output of this is a blue color I don't know why it has to be blue but it is that means that we have to do something to that in order for it to work in this gray input right generally that you can't as far as I know use different colors together maybe somebody can correct me there but anyways so what we want to do is add in something which honestly I it's pretty hard to wrap your head around what this actually does but it's called the vector math node all right here we go dragging this vector math node and you want to take the velocity and put that into the top input and you want to take the velocity and also put it into the bottom input and then you want to select from this drop-down list dot product now if you can't tell I have no idea what any of this means honestly it's no idea I just did a lot of research online and found a few screenshots of this and figured out how to make it work in this example right I don't know what dot product does I don't know why using both in the same thing but this is the way that you can get this gray input to something that you can actually use so that's what you do somebody I'm sure will write in the comments what the dot product what this is actually doing because I have no idea in fact if you do know maybe you can come here so once we've done that then just like what we did before with the you know giving the flame of strength we want to be able to control the strength of this effect so I'm going to take the value of this put this into this math node here by the way if you didn't see what that was that was a converter math node and then set this to multiply turn it down to 0.1 put this into the color ramp node take the output of this color and then put that into the emission input then if we go back to our to our scene over here if we give this a little render now hopefully yeah it's working pretty well if we go in here we should be able to see the particles that are closest that our slowest which are basically the ones down you know in the flames because they haven't really picked up speed yet they're an orange color and the ones that have got a lot of speed and I sort of rocketing out of there they're a bright white color you know so yeah so basically that's basically that's all you need to do but to make it so that it fades out what we're going to do is use a mix shader' node combined it with a transparency shader node flip them around make sure the transparency is in the top input and then take the output of this multiply node and use that into the mix shader' so if you have no idea what I was talking about then basically it's making sure that when it is dying when it has low velocity its fading away it's got a low trend it's got a higher transparency amount then as it picks up speed it starts to use the emission strength which is one you can increase that to two actually that's probably all right yeah and that looks pretty good so if we look in here you can see that the ones that have got a low velocity they're kind of transparent it's a little bit transparent in there and that's what you want you want them to fade away as they as they lose their their velocity and that's what we've done so that's basically it let me just pull this back a little bit let me see if we can get them more Oh No kill me kill me oh that is why you always save your blender file people always save because that happens and now we're back to square one okay ten minutes pass and we're finally back to where I started before so that's why you always save your files don't make the mistakes I did so uh all right good news is only that time I was able to fine-tune this these little amber embers to work even better increase the strength to fifteen which I found sort of gave it more oomph and then I gave it even more of a push because the trouble is is when it starts off in the smoke it doesn't have a lot of power behind it so it starts off slow and then it kind of builds up speed in here when it should really be dying off so so that's that's what we're trying to combat so I also gave it a little bit more of a normal push which means it is ejected out of there from the start with a little bit of force which sort of pushes it into the into the fray a little bit more and then if you are increase the random lifetime of the particles and also drop the lifetime of them to say 30 you should find that the embers sort of die off where they sort of should sort of sorta and who save it okay because I'm doing a little all right please don't crash on me again good all right so they do start off like a little bit of yeah like faded away and a little bit orange and they can sort of build up speed here it would be ideal if they could sort of decrease in speed as they go up there and I've tried various ways of doing that such as giving this a maximum fall-off and some power and all that kind of stuff doesn't really have much of an effect on it because it basically the particles then never get up into the stream they sort of fizzle out and die so you basically you have to have it so the particles sort of die off on their own but at least we've got it so that when they're moving slow they're a different color and they're less bright so at least we've got that going for it right so so yeah that's pretty much it so what we'll do now I just change that back to uh yeah strength to like it was in the recording but I forgot to do for the redo I hate redoing stuff we also probably want to give it less embers so let's try let's go 200 over 100 frames like that and there is a lawn mower outside so I'm just going to close the window but you toriel started off so well now it's all shambles all right and then down here underneath the render render mount I'm going to drop the size so they're actually something a little bit in a more reasonable and also going to increase the random size so that some of the M is a big and some of them are small you know not too small but something maybe make them a little bit even smaller still I mean I used a point zero one oh yeah something like that that should be good now the cool thing is is if we enable motion blur down here on this cycles render settings these embers will actually now look like real embers do they have this little streak like a motion trail behind them and that's where it starts to look really cool yeah before that like I think with the old and internal renderer if you rendered volumetrics you couldn't have motion blur inside the volumetrics so it was really limiting in like you couldn't do cool explosions you couldn't do this Amba stuff so it's cool it cycles is like gradually getting there the last piece we have to do though is the the GPU once that's done then we can clearly have some fun with fire now one other thing we're going to do is well just for the sake of it and so that when we add in a scene it actually works is add in a lamp so even though this because the thing is is even though yeah as I was saying even though we've given this a multiplier value of 20 I find like if you increase this like higher so that actually affects the rest of the scene then this white will just become like way too blinding so like the high you increase this to you can see like the less of the detail of the fire you can see like it's just become like one big white blob but we would like it to have more of an impact on the scene around it because if you add in a plane if we drag this in here and then just drop that underneath it let's just let's delete that lamp just the lamp just for now just so you can see how it effects it you can see that the the fire does light up its surroundings a little bit but not enough like it's a fire should really be coating everything around it in this sort of a warm glow like it's pretty bright right so so what we're doing is we're just adding in a a lamp down here which is just it's faking it like it's now it's not going to be it's not going to be flickering with the rest of the light of the fire as well so it's not as good but it's just going to give it just a little bit of a push above the standard so you can see the glove which should now be a little bit more out there like it should glow a little more eyes they're not going as much let's go 200 Oh also we can go ahead and change the background to be black that probably helps and there we go so now it's got a little bit of an orange glow to it um hang on a minute I forget should be even more than that oh I know why I think I know why I can see the shadow from the actual plane let's increase the let's bring it up a little bit there we go now the fire is actually showing through like it should so let's drop that to I don't know like 100 good good good and maybe with this material here for the actual um the the smoke thing maybe we can make it so that doesn't actually render any shadows cast shadows ray visibility shadow all right let's try that hey that worked immediately I didn't expect that to work so well so now it's not yes I'm casting a shadow so that's good that's problem solved alright so look at that we've now got some awesome looking fire but all and that's how you do it that's how you get great-looking fire with embers added and it looks it looks pretty good what I'll do now just really quickly for this last little piece and before my computer completely collapses from all this stuff here I'm going to add in something which you can download I'll put this on blender here so you can get it is just a pile of sticks right here because that is what the tutorial is really about it's about you know making a campfire isn't it so what is the size of this in real meters in metric let's see what it is okay so the size of that's 2 meters that is a pretty big fire okay so we'll scale that down cells directly underneath the fire there now if you really if you wanted this to be like a physically accurate fire what you would do is each one of these sticks and I'll show you can do it right now you can follow along with me is you enable smoke and then enable flow and that's basically it you set the surface to 1 so that the the fire actually hugs the surface of the sticks a little bit more you want to give it a texture give it the same texture that we we had on it before as well and seems to already have an animation on that offset doesn't it okay let's try a try 10 no the end of frame okay delete that kid I think there's already a keyframe on that because uh when I added the I use these sticks in a previous scene so I think it's it's using that that old animation I'll set that to zero okay so now that should be flickering a fair bit maybe too much so from frame zero to 100 we want the offset to be like 5 okay so once you've done one stick all you need to do is select the sticks which you're going to be burning and this is important when you're making a campfire you don't want all of them like not every stick in the fire is burning let's have a look at the reference photo and you can see this stick up here is main one that's not burning a sizzling it's got a little bit of smoke coming over so you could use the smoke emitter instead of fire and it's basically the ones at the bottom the ones that are like deep in it those are the ones that are burning like that they've now because when when I don't know if you've ever had a campfire before if you have a social life no I don't know if you've ever been to a campfire or seen one in real life but yeah it there's a lot of sizzling when a lot of you know the the fresh wood it's still wet and it's you need to use a lot of like newspaper and and tree bark and leaves and all sorts of stuff just to start the thing and then as the the fire like as the wood cooks and dehydrates then it actually starts to burn so these ones at the top these won't start burning until they've broken and fallen into the bottom part down there so these are all the sticks down here and these are the ones that are going to be burning so oh wow I found that with pure luck you want to select that look basically the one with all your settings aren't that you want to copy make sure it's set to fire that was important you got to check that and then hit ctrl L modifiers so now every single one of these have the exact same settings and also once you've done that you want to go ahead and hi all of those and then the rest of these these ones up here we can give them smoke collision and these can just be yeah just collision ones or if you want you can have them sizzling as as smoke instead as you could have them just like that you don't really need a bit of a texture on those those can just be just sizzling away a little bit let's give them a little bit less density in the full-on smoke that usually comes out of them also control L modifiers and if you want anything to be like a collision then you just you know let's say you want this one let's see this one I hear that once we're not going to be sizzling you just give it collision like that um maybe a couple of those could be collision they're not all smoke emitting and that one can be a collision as well yeah you get the gist of it so that's basically that and then you drag that over so that it's on the exact same layer as everything else and we can now probably shrink down the size of this that whoops let's do that in edit mode it gets funny when you scale things in object mode for smoke simulator just it messes things I remember when I did my first smoke some years ago on that big a bit of way more than I could chew for that first simulator I didn't for the burning city yeah I had problems where I accidentally scaled up the cube and and then in the final render I had this horrible like blot Tina's a kind of it was like sort of like repeating the fire in itself and I realize it's because your scale keeps it has to be in edit mode like this when you do any shaping of the actual domain cube and you'll avoid that problem alright but once you've done that then save it very important free all bakes and then go ahead and bake the dynamics and this should now go ahead and bake all of that with that lovely fire so let's pause and see how it goes alright there we go got our fire burn that's a fire with character so that's pretty much it I mean you know this could be improved with obviously a higher resolution of a baked you know getting it up to 128 I haven't got that many hours the so uh but you get the gist of it you can also improve things as well this is another little tip here I'll just throw in here if you use a texture and then just you know just like what we did before give it like a cloud texture and then use a value of like one like that contrast it whatever this will actually affect the smoke so that you could then place an animation you know frame one and then a frame 100 make it move like this way and then what you'll actually get when you do that is the smoke well actually it will appear as though there's like wind in the actual smoke and that's what I did for my my final animation as as well and yeah when you render it you'll get something that looks like this and that's it that is fire in a nutshell so placing this in a scene that the scene is up to you whatever scene you put it in the scene I put it in with this very complex looking forest camp fire scene here and I'm going to be doing a tutorial on how to create this grass in the next tutorial so in this grass i used a product which i haven't really used in any tutorial before but it's using the grass essentials pack which is something that the team of blend goo has been working on for the last few months and it allows you to finally create realistic looking grass like this with ease so that's all I'll say about it but there will be a tutorial on how to create this seen this this this grassy sort of meadow we're going to go for a morning time scene so I'll be doing a tutorial on that one next so look out for that but that's it guys I hope you enjoyed this fire tutorial look forward to seeing anything cool that you make with it so thanks very much for watching bye

Channel: Blender Guru

Views: 386,401

Keywords: blender, tutorial, cycles, fire, Software (Industry), Animated, How-to (Website Category), Blender (Software), Animation

Id: u-zK7Bu8cAI

Length: 57min 59sec (3479 seconds)

Published: Tue Jan 20 2015