Compositing with EXR Files | FREE VFX Explosions

hey guys welcome to this tutorial we're going to be compositing explosions so if you like explosions you're probably downloading this explosion because you want to learn how to composite it so this is actually a pretty cool render that you're getting it's a multi-layered exr so if you haven't worked with those before essentially what you can do is you can take this multi layered exr and adjust each layer independently so for example you can adjust the lighting on one side of the explosion or you can extract the glow as its own pass its own layer so nuke is really good for this we're going to be using nuke to composite it and you'll actually see how it works if and so we're going to talk on a very beginner level with nuke so if you never use nuke there's an after effects to Nuke Free master class that's included so you can click in the link below if you want to take that Master Class my background has been working in feature films so I've been using nuke on films like Star Wars Avengers across the spiderverse and a bunch of other projects but I started out also in After Effects so basically if you want to transfer your skills really quickly that's software to do it if you're more of a CG guy if you're doing like blender and unreal or Houdini basically all senior generalists in the industry are also composing with nuke so you know for example unreal has an Unreal Engine bridge that connects to Nuke and you can polish your CG renders really effectively so that's all information to know check out the free Master Class below and we'll go into the explosion tutorial uh and explain how we can actually use this render in your own CG shots all right guys so this is going to be the render that we're working with so this is after the composite we're going to do some glows we're going to break out the layers and show how a multi-layer exr work so this tutorial is really geared for people who haven't done multi-layer exr compositing so if you're a beginner this will help you out if you're more intermediate you might see some interesting things in here related to just how to grade stuff so you can probably skip to the middle of the tutorial but essentially that's the level that we're speaking at here so there are four free explosion downloads you can use them in any project or film that you want as long as it's in a file project form so that's essentially what's in the link below as as well as the after effects to n course so essentially first thing we want to do though is switch this project into Aces so if you open up your nuke script automatically when you open the software it's not going to be set to Aces and you've probably heard Aces but I'm not going to do a full uh technical Aces tutorial right now but I will show you a quick understanding that you can understand how it immediately will help you to switch into Aces so essentially to do it you hit s while pointing here and we want to go into the the color settings switch to Ocio and switch to ases 1.2 or ases 1.3 and you can just basically close that and you'll see up here it says srgb Aces if you've done it correctly so what that actually does is the highlights are going to roll off a little bit differently when we grade this explosion it makes it a little bit easier to get a better result uh much quicker so that's one of the benefits of Aces and we can compare to a Aces and non- ases uh footage so this is the same footage this is 8 bit footage there's no high dynamic range this wasn't shot in log or anything like that it's just really normal footage out of a phone and essentially on the right here it's not ases and on the left it is aces now right now they're exactly the same they've been loaded in uh and when you bring them in by the way you just double click it and you load as srgb uh you know because that's a standard color space for an image again going too technical but essentially if we uh gain this down we can bring this line down here and you'll see that it looks kind of flat when we darken it we don't see uh any more detail and that's be expected you don't necessarily have more detail on the highlights but this is kind of what happens when you're in in a normal uh sort of color management workflow here now if you switch to Aces it's just the math and the way that the highlights are being handled if you actually pull this gain down a little bit you'll actually see that everything looks like it has more detail in there so there actually is more detail it's just that when you're not in an ases workflow the way the highlights are managed as you're pulling or pushing them this is doing basically some special tone mapping around the Highlight regions which gives it just a better result immediately so you can see the difference look how flat this looks and look at how much more there was is actually in the image even just 8bit so that's good to know and especially if we're going to start doing explosion where the highlights really matter so that is essentially why I wanted to just really quickly touch on that even though we're in a beginner tutorial so uh we're in Aces and this is the image that we can start with so this is my little node tree here if you've never worked with nodes um again go check out that free tutorial but I'll talk through it on the still beginner level here just to not lose anybody so we have the explosion we're going to pull it into nuke so you just drag in the image sequence or you do a read node by typing read and then you can load in the image by just finding the path so I'll just paste it over here to the side copy and paste and we're going to do this from scratch so these are the shuffle nodes here that uh will break out the different layers that are stored in here so this is not like a normal movie file it's not a quick time this is an exr that has multiple passes in it so this is uh multi-pass CG compositing so if we click here and we go to this little tab we can actually see the layers that are stored within this image and that's why if you go download this you'll see that the file size is kind of big because there's a lot of data in there and it's all a high dynamic range so there's a lot of data uh being stored in one single frame for example so if we want to see one of the layers we can see we're looking at rgba which is kind of like the main area that we normally composite in but if we go to any of these layers we can actually see the the aspects of this explosion so we can look at different uh lights for example uh and and we can see like just the light on one side of the explosion so our ability to look at those layers I can brighten it up just to see a bit better we can actually break these layers out and recombine the image uh in a different way so this is our main image that's combined but we can break those layers out and recombine them so that's essentially what we're going to do so I'll hit tab here and type Shuffle and Shuffle is the node that you're going to use to essentially pull these layers out into our main rgba layer where we're doing the composit so these layers are stored in different layers um but we want to be working all in here so it's basically taking the data from any of one of these and we're putting it into here and that's where we're doing essentially the composite so I'll bring this down I'll hold control to create a little Dot and then I'll just bring it off to the side here and I'm going to uh grab a few of the the uh light layers that are in here so essentially uh first we'll grab the spotlight side all so we have a a spotlight from the left side I'll just copy and paste this so contrl C control V you and we'll keep it connected so they're always pointing into the same image here and we'll grab another one Spotlight all which is just from the other side copy and paste double click it and we the one we're double clicking on you see the shuffle 8 this is the one that we're opening in our properties panel over here so we close this one and then we'll grab another one let's say the second fire one of these um channels I think are empty so some of them don't have anything I believe I think it's this one the uh no map all so that's like a kind of a ambient light overall I can just double check here to make sure so we have Spotlight Spotlight all and NV no map all so that's like our three main ones if you forget the names you can see them here Spotlight Spotlight and uh end light and then there's one more layer we want to pull out so I'll copy and paste and we'll just click here and we'll click on all emission so this is going to be the essentially the light the emissive light that's coming out of this explosion so essentially what we want to do here is we want to recombine these back together together so we actually don't need to uh see this original image anymore what we're going to do is take these layers that have been pulled out and recombine them back together we're not going to do anything to the layers yet we just want to recombine them so that they match the original image so what we can do is we put a merge node and we see this node which has the light and this node which has another light I'm hitting one to switch where I'm looking at the different nodes here and we'll say a and b and then we'll merge them together so that will combine the two so if I hit disable and enable you see they're being merged together we want to switch this to a plus whenever we're adding light uh of passes together it's always a plus so copy and paste this uh and I'll switch the input here by hitting shift X so I want the a to always go over the B that's the uh good way of doing compositing so if you get more interested in Nuke or if you're already intermediate you already know this so A over B and then A over B so I'll hit shift X and then A over B so essentially we're just merging these all together if you imagine Photoshop like layers each one of these is like a layer so if I if I put little Corners here by hitting control it'll be a little bit more visually understandable so you can imagine uh that each one of these is like a layer so we have like the the base image we have another image being merged over that one another one going over that one Etc now what is interesting about this is if we look at the end result and we compare to the original we should basically have the same result it looks like we might have one slight pass missing here so we could probably go in there and find whatever that one is so it looks like we just have one more pass called pyro uh volume light all so we just need that extra one it just gives the luminance a little bit more uh in there so we'll just connect that uh I don't think we'll grade that one for anything but we want the beauty to match the recombined version that we recreated here just to make sure that we're doing it right so if you look at the end and then we hit two on our keyboard so we can have multiple inputs so if you're new we can hit two and we can hit one on your keyboard and you can switch between the two so that's essentially what I'm doing I'm hitting one and two and we can see there's no difference between those two different images so we've recombined it and we're all good so that's that's cool but it's not really doing anything but now what we can do is go in between any of these layers and we can add a grade node to adjust the look so for example if we go up to let's say Shuffle seven that has this uh light from the right side if we put a grade node by hitting G and we disable this we can grade this up if I look at the grade by hitting one so if I hit one one here and one here we see that it gets brighter so we're making that light brighter and we're recombining the image together so let's go to the very bottom and let's go a little bit further in the image so we can see more clearly exactly what we're doing we can see we've made this uh light that's on the back much brighter so if I disable it and enable it we can see how we're actually modifying the image in its different elements to create a result that's different so I'll disable it let's put a grade note on a different one just to show it and we can grade up I'm looking at the end of the composite here so my viewer node is attached to the very end after we've combined them all so I can put a grade on any of these layers and we can see the modifications as we do them so we can go here we can grade up just the emission so this is going to be how we can create a brighter or darker uh emission so that's going to control the glow or the color of the fire and the burning fuel essentially that's in this explosion so if I if I bring it down all the way way we see that just the remaining layer which is this uh volume light all now my original comp I didn't even use that layer uh for whatever reason so I'm just going to disable it for now we're just going to leave it off this comp because I don't actually need it but it is there if you want the extra control so let's look at the end result right now we have no fire right now we have fire for enabl so that's what this grade is doing so that's the the basic idea of multipass CG compositing is that you can break out all your CG layers modify them in a really really detailed way and then you know reassemble them together now what we want to do is actually start to create a nice looking glow on this explosion we're going to comp it as if it's like nighttime um we're not going to put it on a background or anything but you know explosions can look different based on how exposed your camera is so if you're basically if your exposure is higher or lower it's going to actually affect how much glow or how much detail you're actually seeing for example if you're at nighttime and there's a person standing in the night and and you're exposed to them meaning you see all the detail on the person something as bright as an explosion would probably appear almost Pure White you'd see almost no detail at all all the the detail gets lost because the camera is not exposed to that detail so this is where an understanding of Photography comes in and exposure so we're going to we're going to kind of composit it where it still looks cool and we still see see some of that detail so we're exposed a little bit into it and that's something to keep in mind as we move into this so explosion a little bit too red for me right now so first thing we're going to do is just start to take out a bit of the red so we go to the gray note we'll click on one of these little color wheels and we'll just start to pull down the red in here and you see we're only doing this in this little layer or this little stream that we've created uh in only the emission path so if I double click the shuffle it's the all emission so I can take a little bit of that red out uh and make it a little bit more of a natural color for an explosion which is this kind of orangish uh result that we have here now what we can also do is let's start to just add a glow to it and see what happens so essentially the glow is something you have to kind of modify quite a lot sometimes when you're doing explosions u meaning it might be too much glow at one frame and then not enough glow in another frame so a lot of times you have to manually adjust your brightness to get it to look good but essentially what we want to do is we'll start by just getting a glow in there just to see what the base will look like so I'm going to put a ke node by hitting tab typing keier and and this node essentially lets you target the highlights so I'll hit a and we can see that it's creating an alpha targeting the highlights this is basically looking at the brightness of the image and I'm going to increase the value of this little slider here usually the vast majority of time you're only using A and B which basically selects the range of the highlights that you're trying to Target now because this is essentially working Aces and we have a high dynamic range explosion uh if we sample here by hitting control we see the values are really high like eight uh in some of the values or two or three so so right now it's only selecting between zero and 1 but we want to really Target into the highlights so what I'm going to do is go to the B and hit the arrow key and hit up and that's just going to allow us to Target even further into those highlights so we can really Target just the very very bright areas so now that we we've Target it we we need to do something with it so I'm going to hit preal node by typing uh hit Tab and type preal and this will essentially multiply the alpha that we've created against the colors of the image essentially cutting out the bright areas that we've just Target so we have just the bright areas and the color combined so essentially like this and then we can put an exponential glow node so this node will come uh in the script that I provided you guys it's a custom node that creates a nice looking glow and uh yeah we have a nice looking glow on here now what we can do is we can take a merge node and plus it onto the original so we switch this to a plus and we have a glow on our explosion so this is a pretty basic glow but uh we start to see the idea coming into play here now you see at the start it's pretty it's pretty uh bad it's like if we go a few frames back it just gets like a very like a like a circle almost and this is where you have to start doing a lot of manual key framing on your explosions um to get them to look good to get a little bit more of a natural camera glow um if we look at the one that I did um this is essentially what I did I I stacked a few glows together to essentially create a more natural uh essentially glow around this we don't want it to be too much of a ball around it um and usually there's a broader glow that's softer so usually at least two or three glows is what you're going to need even when you're using exponential glow now there might be an exponential glow node out there people make their own nodes that that glow differently essentially um that might do a better job but that's just what I had to do in this specific case so when the values are very different in explosions uh it's pretty common so like for example on this Frame completely blows out so what you would have to do to fix this is put a grade node just before the glow and just would just bring it down so we can bring it down to somewhere like here and set a key frame by hitting right click and hit set key and then we can just go forward in time and then okay there's no more glow so we just bring it back up and essentially we just do that and try not to make it look uh you know there's no frame that's basically uh like a broken glow almost which can definitely happen so I'll bring this down even more um we could expect definitely more glow on this frame for example where it's like really just exploding um if it was a real life camera and we wanted to be really picky we could look at some real reference and things like that um I would go check out the reference of um I believe it is Oppenheimer and but but not the actual film itself look at the behind the scene footage of how they filmed the explosions you can see some pretty cool gasoline explosions in those examples so I'll close all this and we'll do another glow and then we'll just make this one have a higher spread maybe we'll blur it and then we'll bring the brightness like way down so we have like a broad glow and we have U a little bit of tighter glow and we can add that on top U maybe that's a little bit too much so we'll just again key frame it manually um and then we'll just kind of play through so like I said if this was if we were doing this for a specific um light condition I would go straight to reference even for the glows um I still go to reference all the time to to think that you can memorize exactly how things look in real life I don't think it's a good idea I think you should always look at reference um at least the first time you're doing it and then once you get the look locked in you can pretty much just match what you did that's typically how I like to do it um so we can go back a few frames like here it's getting a little bit too much again on the broad glow so we can bring that down and the original glow uh could be good I think it's I think it's not too far off so that's kind of uh the base glow that we got here uh one other thing that we can do is if you need to you can play with the uh exposure right away so right here it starts to get dark pretty quickly um so basically what I did in this comp I won't redo it completely just to make the video not too long if you want to go in this comp and look at it you can check it out but essentially what I did was I targeted the highlights and just made them a tiny bit brighter uh first of all so we take the same Technique we just did we do a ke node and then we just use a grade node plugged into the mask and then you can just bring it up and down so it's only hitting the highlights and a few other adjustments make it less red um but the real adjustment here that's interesting is that if you want keep it hotter at the beginning we're only in the mission layer here but if we target essentially the shadow areas even though the whole thing is pretty bright we take the key note and Target Shadow areas by hitting invert and we can play with the range there to really Target those uh Shadow regions um essentially what I did was uh brighten them up a tiny bit CU usually when an explosion is happening it's almost white you're losing all the detail we're not seeing all the cloud detail right away and a lot of times you want to actually just lift those blacks a little bit so that's one thing you can do is just uh Target those regions and we can get something like this and now this is something that you can key frame off so again here's our high our shadows that are targeted I blurred it a tiny bit just so we get the whole region and then I have this key framed uh grade with rgba and as it goes on we basically fade it off so the grade is going to turn off uh over time so that's a little bit more intermediate if you're a beginner that might be a little bit too far for you but I just wanted to show you guys and you can sit there and kind of check it out if you want so you see the the effect that it has we start in a more kind of yellowish brighter thing and then it's kind of fading off into the darker tones where we see a little bit more detail and why we're doing that is because we're removing the detail towards the beginning so if we go towards the end um we're we're keeping the detail lost for just a tiny bit longer and you see that that's the effect here so that is kind of what we got going on we can compare to this one you see how you see how right away we start seeing detail like we have like very bright and then immediately um we're starting to see like almost Shadows already it almost feels like electricity versus like this one feels like everything is still burning and then like the fuel starts to go um we could adjust the timing of that as well but doing explosions and glows like this you can see it's a lot about timing and Grading it's not just about one frame making it look good but you got to adjust across time so that is essentially the two different ones we have here so let's compare this one that I just did and the one I did earlier which has a little bit more detail and you can see uh just by grading the highlights as well we get a little bit more detail in there now one thing I like to do with explosions as well uh this is a little bit of a cheat but uh we can do it uh what I'm going to sharpen it basically so we put a sharpen node and what we can also do is a log to Lin so we put a log to Lin node we switch it to log space and then we copy and we put at the back uh basically right after and we switched it to uh back to linear and we have the sharpen in between so that's usually sharpen needs to go in between these two nodes um I won't go into details of it right now but just basically always do that you'll be fine uh it'll just sharpen it in a better way so if I zoom in uh sharpening explosions pretty awesome technique uh just always works even when you have like pretty detailed explosions you just get awesome looking uh stuff in there so if you want to make your stuff look good uh sharpening explosions I would recommend it I think it's pretty cool so that's about it for this tutorial uh if you guys like it make sure to hit the like button I know this is more beginner SL inmediate uh different levels there for different people but I think it'll be useful for everybody and you get the free asset that you can use in your project so hopefully that'll be uh good for you guys and if you want check out the after effects to n course if you're new uh and downloading these for the first time that's about it thanks guys

Channel: Compositing Academy

Views: 7,464

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Id: Ps7LQcKNPWc

Length: 21min 52sec (1312 seconds)

Published: Sun Feb 04 2024