How to better ANIMATE a STATIC SKY in NUKE | Comp Lair: Live Tech Corner S01

so today we're going to talk about something that quite often we are asked to do in compositing which is out of a static picture of the sky we need to give it some movement we're going to look at two techniques we're gonna export the traditional one that probably is not used for the majority of you and then we're gonna explore an alternative one that probably is news for either the majority or to some of you and i think this alternative way works better but let's go to the traditional way so normally what this means is you're gonna drop a transform and then move the pivot down and then you use the skew on next so you can give it this cue this technique for me has a few problems but we're gonna use this with some alternative controls so you can do this a little bit better if you want to proceed with this technique anyway and for some situations this is probably enough but we're going to explore an alternative technique as i said but at the moment let's just beef this one up so what you want to do is to have this setup to work in any picture so what we have to do is to first set up the pivot point so we want to take it from the input and you want the width divided by 2 because we want to start at the center and then this will be the height so if we do this independently of the image that you are inputting the pivot will always be at the center of that image independently on the format so now you have to make a decision on where you want to put this height wise so if you take this divided by 2 this will take the maximum height which is not what we want what we want is this to be 0 either 0 or with a certain range so you can actually put this range that you want as an alternative control but at the moment let's just say that this is 0. and now what we want is to animate this so first of all we need to parent something that will do this automatically without using keyframes so we're going to use the frame then we could introduce a certain speed and this speed variable that i'm creating is not created yet so that's why it's giving me an error so now i want to create this variable here and i want to introduce some values this will be my range in which i will move things and then also what i want to do is to also introduce the ability of offsetting the image because now if i introduce some speed probably this might be a bit too much already and i want to have the ability of starting on a certain point that it's probably not the initial picture that i have but i want this for example to start a little bit to the left so we need to introduce an offset in here so i'm going to create another one and call it offset and we're going to go from i don't know minus 10 to 10. and now here on the transform i'm just going to go on this cue i'm going to put the frame first of all with my offset so now all of this is gonna be multiplied by a certain speed so this is how we have to do and now if we go on our first frame i probably want to start this from here for example and so this will make the sky work like this and then you adjust this speed if this is still too much that's okay if you want to start a little bit before that's okay too let's not forget that of course you know you're taking the image as is so you're showing some of the blank areas in here to fix this you have to go into the frame in which this is showing more for example the first one and you probably have to increase the scale a tiny tiny bit okay like this or if you don't want to grow from the pivot in here you drop another one here which is probably what you should do anyway and then you put this coming from the input and then you're going to grow from the center until you get that occluded you put a crop that's it so this is the foundation of a tool to animate any sky if you want in this traditional way but this is if you think about it a really weird way of introducing parallax yes one part is moving less than the top one but that's not what parallax is all about parallax is moving things more or less in depth not in a flat plane which is what we're doing in here we know that this is in reality has some depth and that's exactly what we want to introduce with parallax we want to introduce more movement on some of these puffy clouds rather than other ones so although this is a technique as i said that you can work with and sometimes does the job but i think there's another technique that will work much better but if you want to go with this one you can compile this into a tool give it like very specific controls which is the speed offset and scale just to get rid of those black areas and you're good to go with this technique so the other technique that i want to explore is based on the displacement method so this is a 2k plate so for the sake of speed i'm just going to put the reformat here and i'm going to put discount 2.5 okay it's enough for the example anyway and now what we want is to use a card and i want this card to follow a certain camera that is generic for the moment and if i want to have this picture as is although in the 3d space i need to link these two so as usual i'm going to link the focal length to lensing focal and the horizontal aperture in here as well so now i just give it a little bit of z in here so now if i take the same format as my input in here which i will and now this picture is exactly the same as the incoming image okay although in here i'm on the 3d space so now what i want is to introduce the displacement node as i said and if i want to display things with some detail i need to bump this one up to like 100 by 100. now i want to use a gear that i'm gonna extract and have control over the luminous of my incoming image and then i'm gonna use a display geo here and this will be my displacement map and i'm gonna displace the car in the way that i want so now i want to isolate the areas that i want to displace as a starting point let's just do this see how this goes and then here on the displacement i need to set the source to alpha because this is outputting things in awful you also have the ability of course to output these things from luminous immediately but i want to have control of what happens on the alpha and i will definitely change this at some point so i need to have that instead so now if i look at my 3d space i don't have these things there's one problem though which is i don't want to extrude the white area so i need to isolate that area so i'm gonna isolate this area like this i'm gonna stencil that from my selection like here just give it some of this and then let's take a look okay so now i don't have that part being extruded which is exactly what i want so the difference is this now do i want to extrude this more or more broadly yes or no it's a question that you have to ask depending on what's the goal so here we have that thing being extruded like that but i need to have broader areas but we're going to take a look at this let me just point out that as soon as you use the displacement geo now the image is not going to be the same as this one because of course you are growing the image more so the features will go outside your canvas so if that's the case you probably need to reach things but for this example i'm going to ignore that so now what we want is and i'm going to show you this on the 3d system is to now move these guys and we're going to do that via the actual displacement juice so we have a part in here that is called offset and look what it does it does this so this will definitely introduce some parallax between your clouds and it's a very very easy thing to do so let's just do this in here and let's do that live you see all these things will work now you do have through parallax now okay the problem is the selection is very steep in terms of like these little mountains that we have in here so we need to add a blur to our selection and we can do that on the actual displacement map like that and then you're gonna have broader selection all of these things needs to be really subtle whether it's with the traditional way or with this one these things need to be really subtle and you'll see that to get not weird results and also depending on how much you are moving you probably will end up with big numbers here on the blur but we'll adjust this as we go so now we need to link this in the same way that we did before with a offset and the speed let's see if we want to actually start a little bit before we do cool so let's now cache this so now if you look at it now we do have two parallax you see now we have movement that is not designed on different parts of our image and now if you want you can even mix the two concepts you'll have the best of both worlds but let's now try to refine this even further so you'll have even more movement even more you know detail so what we're gonna do is from the actual input in here we're gonna create with the same form as i'm gonna use these remove again we're gonna use a noise and then this knives will be with the pattern that we want and we will also want to animate this with the same one so frame and then we're gonna get this with a certain speed something like this so you see that this is moving automatically and have the ability here of changing the speed so there's no news in here i don't think but anyway just want to let you know exactly what's happening in here so now i'm gonna inject this in the main pipe so this noise will suffer exactly the same transformations that the actual image so i'm going to use the shuffle copy i'm going to call it vectors distort okay so now if you look at it in here with the layer contact sheet you'll have both of them cool so now both of them will come into the main pipe and i will have them as well in here so if i look now with the layer contact sheet i have this guys as well cool so here's what i want to do i want to now shuffle them out and then i'm going to use them on a4 u and ford v channels so i can then use this as my distort like this so i choose the forward here and those are the ones that i want to distort so you see that now i'll have you know this little detail in here and they can be bigger or smaller depending on the actual size that you have in here so it will be up to you so we need to be subtle with this i'll probably go a little bit overboard just to show you the technique itself let's maybe start with this and then to ease this a little bit more i'm gonna drop a blur here just at the end so you'll ease this a little bit so let's now see how this will work in just a few frames so you see that you have some of that rippling coming from the noise it's very subtle but you see that you have some of these things this needs to be subtle anyway this is the result with both techniques applied and you can see that you we have like a very nice movement very nice parallax that is much more realistic than just that initial technique you also have some movements some rippling effects on the clouds that you can also have ability to change and that's it i think this works much better than the traditional technique it's very easy to control you can also compile all of these things into a tool give it like very specific controls very similar to the controls that you actually had on the other one of course you should also give the ability to the user on changing the selection of the areas that you want to have them moving something like this will be fundamental for that but the technique itself is very similar to the other one in terms of controls so this can be compiled in basically the same way and then you can use this image in any way you want i've built systems like this to my teams in movies that we all know so this is a technique that works really well and i encourage you to try it because it's so so easy and it's so so much better

Channel: Comp Lair

Views: 844

Keywords: animate clouds in nuke, animate clouds, animate sky, sky replacement, sky replacement vfx, comp lair, the next level, nuke tips and tricks, vfx, advanced compositing, advanced nuke, nuke tutorial, vfx geek, nuke advanced tutorial, compositing, nuke, foundry, Corridor Crew, Movie VFX, hugo's desk, cgmeetup, vfx guru, marvel, dneg, ilmvfx, weta digital, framestore, cinesite, milk vfx, mpc film, mpc episodic, lumapictures, pixomondo, trixter film, Rodeo FX, Digital Domain, rxpvfx

Id: qAmBwV1-Cco

Length: 11min 46sec (706 seconds)

Published: Thu Aug 12 2021