Shuffle and Channel Management | Nuke Compositing [Beginner / Intermediate]

hey guys welcome to this video uh this is just a visual explanation kind of going over the shuffle node which i think a lot of beginners um kind of starting out kind of struggle with and probably for good reason because if we look at the old shuffle node it's super confusing uh not intuitive but i'm going to really kind of break down the new shuffle node and kind of put this to rest uh hopefully so we can go over this kind of visually understand what this is actually doing and hopefully get a better understanding of it and then later on in the video i'll go over some more intermediate uses of the shuffle node um so if you're not a beginner you know maybe you can skip past this part and maybe you'll get something out of this potentially so first i'll start off with just really the basics of it and kind of what the shuffle node is useful for and so if you've been confused with this hopefully this should help so if we get to it here i'll just quickly go over uh the basics of the new interface again which is uh here we have uh channel sets or layers so again in an exr picture we have multiple channels uh channel sets that can be stored uh and accessed here so for example this car is not just this red green blue render of a car we can actually hop into one of these layers and see different aspects for example if we want to see just the reflection layer we can look at that and see just the reflection here so that's this tab the layer slash channel set and we have this layer here which is the the specific color channel that we're looking at so red green blue means it's combining the three of these but if we hit red green or blue on our keyboard rgb we can see that that little tab up here is changing rgb and we can go to alpha as well and there's one more tab up here that is less commonly used but it's still there and this is the specific channel that is shown when you're looking at the alpha channel so if that's confusing it kind of is but if you look at the alpha channel we're looking at just the actual alpha this car but if you want to see something else in this alpha channel so if you just want to quickly access it by hitting a on your keyboard you can actually replace what you're seeing in that alpha channel by using this little box here so maybe we want to actually see the depth of this car easily so we could actually just switch it to depth and then if we go to the alpha channel now we're not actually seeing the alpha we're seeing the depth of the car so if i take the gain and i slide it down and hit these little arrows here uh we can actually see the depth of the car uh stored um it's not actually changing the channel it's just seeing uh it's changing the channel that we're looking at uh in this here so that's that's kind of confusing a little bit but usually i just keep it on rgba.alpha because when i hit the alpha uh on my keyboard i want to actually see the alpha of the car [Music] so if we continue on here uh we just look at this so this is our basic render uh if we look at this here so we have the rgb layer which is made up of the three color channels uh like we've talked about probably a few times but if we look at the first use of a shuffle node so if i create a shuffle node at the top here [Music] create a shuffle node so this is our new nuke 12 shuffle node if i just look at what this is doing essentially what's happening here is this node is passing through the color channels so if we're looking at uh if we look at it like this we see that from the b input so this b pipe like our main information pipe uh you're getting the red green and blue channels and these lines show what information is actually passing through the shuffle node so the red is going into the red so red is staying the same green is going to the green and blue is going to the blue so because they're going into themselves nothing's actually changing this is actually just doing nothing right now so if i go to the shuffle and i actually show you guys this in live let me just make this bigger so if i go to here so i say i have the shuffle note here and i take the rgba red and i put it to this little black button i can actually delete the red channel by doing this so if i press this black button you'll see the red channel actually disappears and the combined layer the rgb combined layer is turning cyan because we only have the green and the blue channels remaining so if i reconnect that red back into the red we'll see we have our normal render again i can do it with the green just to demonstrate further so we have red and blue and that's mixing into purple because we don't have a green channel less commonly used we could we could actually just disconnect all of these just press zero on all of them so this will make them empty and the white ones will make them solid white but if we make them empty and i could put the the blue channel into the red channel so i can actually rearrange the color channels uh in a way that they weren't arranged before and now you see that the taillights that used to be red are actually now blue because we just rearranged the the channels that's not particularly useful uh but it's just to demonstrate how this this works so normally we just we just drag it straight across like this and the alpha so that's the uh that's the way the actual node works but the way it's used and most practical is that we can basically pull out layers again our layers are stored here and we can bring them into the red green and blue uh main layer that we work in so this is the layer that we render out every time we save an image we're rendering out the red green and blue layer so if i want to be able to adjust some of these layers that are stored in this picture and color grade them easily what we want to do is pull one of these layers out for example let's say refraction we want to take all the information and refraction and put it into the red green blue layer so that's what the shuffle is actually used for it's taking these layers and putting them into the red green and blue layer so we can access them easily so if i take the shuffle node and i just switch this little box here to refraction you'll see that now our image changes so our red green and blue layer which is originally just our car is now replaced uh by the refraction layer so if we look at this we see it's it's pretty self-explanatory uh with that concept so it says refraction red so the red channel in the refraction layer is now replacing the red green blue dot red channel so the refraction green channel is now replacing the red green blue uh green channel so we're placing the color channels in the red green and blue layer essentially that's how it works so we can shuffle a different layer so we go reflection here if we switch it and we'll see that now we have the reflection in this layer and you'll be asking if you haven't done cg compositing before i have a full course on cg compositing but again the reason we're pulling these layers out from their original saved position in this exr file is because we want to easily color correct them and do stuff to them so if we go back into the original comp of the shot we can see we have all kinds of shuffle notes happening here we have a reflection shuffle node specular and specular indirect and a bunch of different shuffle nodes pulling out different layers from that picture and putting them into the red green and blue and the reason we're doing that is we can easily color correct those layers and recombine them with those adjustments made so for example if i just wanted to go to the reflection layer i have it shuffled out here reflection into the red green blue and i can go there and chuck on a color grade i can crank up the reflection make this a really reflective car and then when we've combined them all back together using a plus merge we can see that that adjustment is only being made on the reflection layer so that's the real main use for shuffle and i just want to explain it a little bit deeper and more visual so hopefully that kind of gets idea across there so if anyone's confused still hopefully that will clear it up the other use for it so that's the main use really it's mostly used in cg composing but the other use we have is sometimes i'll use it for if we have an image like this we have this video uh taken in uh just a red green blue video it doesn't come with an alpha because it's just uh it's just a video and if we were to want to mask this like let's say we want to roto off this guy off the background and i took a roto node and i hit made a mask you see that it's cutting out properly so it's just cutting out the red green blue but our video doesn't have an alpha so if i go to the alpha channel you'll see everything is just black and if you merge this over another picture you'll see that we get this kind of plus looking effect and that that basically means that nuke doesn't understand what's supposed to be opaque and what's supposed to be transparent and that's because our original video doesn't have an alpha it's a very simple solution you just create a shuffle node and instead of it being like this which is how it normally looks looks by default you just press this little white button here and give it a solid alpha so if you look at the alpha channel if i hit disable on the shuffle node you'll see that we're just getting a solid white uh channel there in the alpha uh channel [Music] so we mask it off merged over and problem solved so without the shuffle and with the shuffle we see that it fixes that problem of course that's one way of creating alpha you could do it another way you could do a roto with the output set the alpha and it will create an alpha for that and you could pre-multiply that and merge it over and that's going to give the same result so those two things are exactly the same but this head does have a benefit knowing that your shelf you can create alpha channels and occasionally you'll need to do that to create a solid alpha or delete an alpha etc so that's kind of how the uh that's relevant so that's the basic uses and most common so if you understand those two things you're probably good to go um the more advanced or intermediate i guess would be uh these situations and um essentially what we can do with the shuffle is we can carry channels down the pipe so this is going to get a little bit more complicated um but hopefully we can keep it understandable here um so we have this video here this is not exactly practical but i just want to show you how it works and then i'm going to show you an actual practical nuke script that i use this in but i just want to show how it works first so we have the basically just the video and we open up the shuffle actually let's just create a new shuffle so let's say we want to uh shuffle this alpha into this picture that doesn't have an alpha we could do that so we can create a shuffle node and plug it in so we see that the b is being plugged in and we also have a little arrow here that's a so i can actually plug the a into here and from this i can switch this second box down here into a and switch it to rgba so right now again it's doing nothing because we see that the lines red is going to red green blue alpha they're all just going straight and connecting in but instead i can switch it from this a box that we just created into this output layer so if i take the alpha from the a layer so i grab this and i put it into the output from the shuffle node into the alpha channel you see if we look at the alpha channel now we have the car alpha stored in there so if i were to pre-multiply this we see that the car alpha is cutting out the picture so you could also do this with a copy node so you could copy an alpha to alpha so just to show you you can obviously do the same thing with this and pre-multiply and you're going to get the same result what's better with the shuffle node especially the newer one is it's not just with alphas and it makes it much easier so if we go to let's say i want to copy the the depth channel from this car so i want to copy this layer if i gain down on this layer we can see that the depth from the camera information is stored in here so if i switch the a to depth you'll see that it's automatically detecting that uh channel and that's stored in the layer with this which is depth dot z and what i can do is i can store that uh in this output from the shuffle so i go back to the red green blue while i'm doing this and just look at our original image i'm going to switch the output layer to depth and i'm going to copy the depth from a from a into this output layer and if we look at the shuffle nothing is actually changing in the red green and blue because we haven't we haven't shuffled or changed um anything in the the red green blue output layer so that's kind of what we're doing here so we're just affecting only the depth so if we look at the channel or sorry the layer let me go to the depth we'll see that that's actually stored there now so if i go further down this comp and i put my viewer here you'll see that that information is being carried down the stream so essentially what we can do and the reason we're doing this is because we can store channels or layers in this b pipe and we can bring them down all the way and use them later on in the comp and if you're doing a pretty small comp or you know you're not doing more complex stuff yet again this is more intermediate it might not be relevant to you yet but eventually it will be and that's why we're talking about this so now that that is stored in there let's go back to our red green blue so we have this picture we have this information that's hidden but it's stored in this information pipe that we've created if we want to get that information back out into the red green and blue we can actually do that so we put another shuffle at the end here and i'll just create a fresh one so i'll create a new shuffle plug it in here and then i will shuffle the depth into the alpha channel just to see if that information is carried so we look at this now we look at the alpha if we gain down we can actually see that yes in fact we've copied that and now it's in it's in the we've moved that information into the alpha channel so that's pretty cool so we can kind of copy those channels bring them down through the comp without having to you know take this thing paste it down here and then you know shuffle out the depth and do all that anytime we need that depth channel we can basically just grab it and pull it out of the comp out of this stream whenever we want so that's kind of one use and that's not exactly practical i'll show you a practical use of this in a second here this is another example doing the same exact thing a little bit more practical because this would actually be kind of useful and sometimes they'll do this in productions um so we have our original video here and i've degrained it so kind of a denoised version of this this footage and what i've done is what i want to do is shuffle this d grained version into its own hidden channel in here so whenever i need the denoise version of the footage i don't have to keep denoising it i don't have to keep going up to the top of my composite and grabbing these and pasting them i'll have it stored in this information pipe whenever i need it so essentially what we can do here is we go to the shuffle this is the default uh i'm gonna do the output layer i'm gonna create a new layer i'm gonna say uh denoise and then i'm just gonna hit this little button here and it will create the channels to fill that layer and hit ok and from the a input i'll switch it to red green blue alpha and now what i'm going to do is just drag this box into here so now what we've done is if we look at our rgba it's still the same but if we switch to the denoise channel that we just created we'll see that if i zoom in real close here uh we're storing that denoised version of our our footage in this information stream so now if we want to do a projection or something later on like for example i'm later on down my comp i've been working on this comp for a while and if this comp was really big for example we just extended it way down i've done a bunch of stuff but hey i wanna you know i wanna go in here and paint out some of these little rocks as we know we wanna work on the degrained or denoised version of the shot so what i can do is put a new shuffle note here let's put a shuffle [Music] and plug it in and i'll switch this out to the denoise channel that we created and now we see if we zoom in here make sure i'm looking at the rgba channel and so when i pull that out we can see that i'm getting the version without the grain so essentially i'm pulling out that version now i can do my clean plate so i would do a frame hold maybe i'll do my uh let's do it on the frame i'm on so on frame 84. so now that we're looking at the denoised version we've pulled it out into the the red green blue alpha layer i could do some clean plating here and just paint out whatever i need to paint out and then you could add your grain back on top i'm just going to put a simple grain note here for now i'm not going to match it perfectly and then you would merge this back over so i guess you could let's just make sure here so i'll switch this to i'll put mask rgb.alpha so i'm creating an alpha with my brushstrokes that's a little trick here if you guys don't know it there's a little arrow here and you can say i'll put mask rgba.alpha on the rotopaint and we can pre-multiply this so now we've degrained done our painting and we've uh now we can merge this back over our original image and you know if if this video is moving we're obviously going to need to have a camera and other stuff to make this stick but that's the concept you can see how this is useful because whenever we need the denoise we can just shuffle it right back out and i can just keep doing that over and over every time i need that denoise footage i can do that little shuffle trick here and just copy it instead of copying you know different setups from the top especially if you're doing keys and stuff like that that's going to be useful to have a denoise kind of stored in your information pipe whenever you need it so one last example of this another practical example this is probably the most complicated example it's exactly the same thing we're doing here so essentially i have this little sign here that's behind and occluded by a bunch of wires so this is available in my nuke44 class which again all the stuff is available in the description below um but essentially yeah we have a sign that's kind of occluded by a bunch of wires and there's some lights that go around the rim of this sign so i actually used a little bit of this channel management to be able to do this effect more easily so essentially let's just look at how it's made so if i look at how it's made we just have a simple constant i've done a little roto here just a little a tiny little line and i'm masking out a checkerboard so you see that we get this little checkered pattern here and i've kind of just duplicated it and made like a frame and what these are are kind of little light bulbs that are kind of around the sign so i've made them yellow and done all that so that's kind of the frame of the sign and what i've done here is i've put a shuffle node so this is where i'm where we're doing this kind of storing the information and pulling it back out later so i've taken the red channel just one of these channels i've created and i've created actually no i've taken all the channels here it looks like i basically put them into a new channel called strip lights so i just went to new i said strip lights and then i basically created this and i hit okay and then i just take the the normal colors of this layer and store them into this new layer and okay so i plus it over like normal so again we're looking at the red green blue like basically normal composite right now but we have this in the background so if i'm looking at this this merge node and if i switch to the layer i see that that new layer is stored in here so if i ever need to just access the light bulbs of this comp i can switch to the strip lights layer and you see that i have access to them right there so we go down in the comp we go further i've added some stuff some text on that sign and i've kind of masked that out and then i've stenciled it by these wires so i have an alpha of the wires that are in front of this kind of sign here so this is the original picture we have all these crazy wires and so i've i've basically made an elf of that stenciled it out from the red green and blue picture but i've also got second stencil here which is a channel merge so we can see that uh using the channel merge node i've taken the channel of the rgba.alpha and i've stenciled it from the strip lights.alpha and i've outputted a new strip lights.alpha so if i look at the strip lights layer and hit the alpha channel you see what this is doing is also stenciling it out by those wires so now i have that layer stored and whenever i need to just color correct or do something with the light bulbs i have that stored in this hidden layer here and i've used that channel merge to make sure that that's being affected also by the wires so if we go back to the rgba the normal picture and we merge it over okay fine so we haven't done anything we haven't done anything with that strip strip lights layer yet however you can see i've broken this down into its own little section here and i've used that shuffle so here i'm pulling out that strip lights layer and i'm pre-multiplying it so i'm just getting the strip lights with the wires occluding it so this is why uh this is useful because if i didn't use shuffles in this instance i would have had to go up here and copy this entire portion of the script and i would have had to paste it and also mask it um by this uh these wires so i would have had to do something like this in order to get the same kind of thing you know i would have to do some complicated or copied setup that's much bigger but by using the shuffles i i didn't have to do that so i shuffle it back out pre-multiply it and now i can glow those light bulbs and plus them over the top so you see that we're only affecting those yellow lights that are around the frame and they're occluded properly by the wires and we're also adding a little bit of glint to those as well and that's just one way to use channel management i guess layer shuffling down streams of information so that's one example and hopefully that's kind of useful to you guys uh hopefully you guys can understand shuffle a bit more now and if you found this video useful as always hit the like button and subscribe it really helps the channel and thanks so much

Channel: Compositing Academy

Views: 4,830

Rating: 4.9748425 out of 5

Keywords: shuffle, node, nuke, channels, channel, layers, cg compositing, vfx, compositing, tutorial, multi-pass, 12

Id: giI8elFp4QQ

Length: 25min 3sec (1503 seconds)

Published: Sat Sep 05 2020