Nuke Tutorial - Roto Tips and Tricks

what's up guys professor Paul here with another nuke tutorial today we are looking at tips and tricks for the node that is the bane of all compositors existence it is the node that we use in almost every nuke script it is the node that if we had the budget and the time we would send our comps out to an outsourcing agency to do for us because it is the thing that we love to hate it is roto and it is the kind of thing that you're just going to have to get better at you need to know how to do it and be efficient about it because Rodo is involved in like I said pretty much every comp we ever do so let's just dive right into it I've got a script up for a project that I recently worked on a music video for a young recording artist named Tatum Lin I will include the link in the show description the job was to combine Tatum singing here in this take with partygoers in this other take and they were they were captured at different frame rates to create the sense that life is sort of moving quickly around her while she sings kind of forlornly so obviously required a lot of roto so this is a good script to look at just to dig into some some roto options and roto is the kind of node that you know because it is so ubiquitous we kind of overlook how powerful it can be I just want to kind of hit a few high points a couple of things that are really really important and one that gets overlooked a lot in terms of its importance in relation to roto is the full size format it is really really important that you set your full size format correctly set it to the same format as your plate the reason for that is if I attach a roto and I've got something going into the BG pipe that roto now takes its shape or its resolution its parameters its limits from whatever's being fed into that pipe but if for some reason I am let's say I've got let's say I'm putting a grade note in and I'm running this just roto into the mask pipe and I don't have anything fed into the BG if my full-size format was left at the default 2k super 35 when I look through my roto node you can see it is now based on this 2048 by 15 as my plate so setting your your full size format and I'm just hitting ass to pull up my project settings setting your full size format the same as your plate make sure that all your roto nodes whether they have something feeding into the BG pipe or not are going to be the correct resolution one of the most common ways that I will use roto nodes is in conjunction with a tracker you can see I've got a couple of Rodos here I've got three row toes in a row here that are each doing different things I've got this set of row toes that is for her right for her her torso her hair her face the core of her head and this little bit of hair on the side I've got different shapes this is in my opinion probably the most important tip here today is that when you are rowing humans you are going to want to break them into separate pieces you're never going to want to try and roto unless she's not moving at all which is really really rare unless she's not moving along you're going to want to roto each separate piece she is not moving a lot in this in this scene she's just kind of sitting calmly and singing but her hair her head her face are moving much more frequently much more often than her torso right her shoulders are pretty much in the same spot for the same kind of position all throughout so I don't need as many keyframes on the torso as I might on say her face because she's singing right her face is moving a lot more her hair is swaying so it's got a little bit more keyframes to it right the head core has fewer than the face because the face is gonna be changing the most this section the hair kind of moves and this Cullis curls sort of collapses in on itself so it's got a it's got a number of keyframes on it I wouldn't want to try and do this all as one rotor shape it would just be very very difficult and require a lot more key framing than than breaking it up into segments so so this tip super important when wrote owing people break them into segments that make sense based on their movement and on you know real complex rotos you end up breaking them into limb segments you know so you might have a separate roto for the hand if you've got finger detail you might have separate row toes for each individual individual finger you'd have a forearm an upper arm a torso and neck a head maybe hair if you get into the lower body you might have thighs calves feet as all separate pieces right because every one of them is gonna kind of move at a different rate swing a different way some parts might stop moving when other parts are still following through so at by all means break up your row toes into segments when possible all right what else we have going on here I've got two other nodes rotor nodes that are attached to trackers that are following the couch because of the movement of the couch and the parallax in the scene I've got two separate trackers for different sections of the couch and I broke the couch into two separate roto sections so I've got this section that's behind her plus the immediate area she's sitting on and then I've got this section here plus again that section that she's sitting on so I've built a lot of overlap into it so if you look through the different Rodos I've got this section this section this section so it builds up so I've got the entire area that I need for for this I've got this all set up so that I can make sure that I've got her consistently row toad and each piece that needs to be following is following the pieces that it that it needs to stick to and the way the way you do that if you are new to roto new to Nuuk maybe is I've got my tracker and I go to my transform tab create a new roto shape a new rotor node that's just the Oh keyboard shortcut and I want to connect the information from the transform tab on my tracker to the transform tab on the roto node and it's important that I have the route selected this route directory all of my rotos all my layers anything that I build in here is gonna sit underneath this so I want to make sure these are connected I'm holding down ctrl o on a Mac I'd be holding down command and I'm gonna drag from the animation menu for translate to translate from rotate to rotate from scale to scale and from centre to centre so now the roto node is doing exactly what the tracker is doing in terms of using that information that you can see now I've got this green expression arrow to show that that is connected okay so that's that's one way to get tracking information into into roto another way is to actually do your tracking in the rotor node and there's kind of two ways to get to that you can do a planar tracker node which is just a roto that has automatically has a planar tracker layer built into it and that's how I did a lot of the rotos for her that's why they were purple I just did really simple planar tracks for face torso etc and that's how it generated the various shapes there another way to do this is with any standard roto node you can turn any shape into a planar tracker if you right click on the shape you can choose planar track and it just turns it into a planar track so you don't even need to necessarily know ahead of time that you're going to planar track you can just simply start with a roto node and if you find that oh this would be this shape would really lend itself to planar tracking well then you can just switch it just by right-clicking on the on the Bezier and choosing planar track so those are two different ways that we get tracking information into the road oh and and whenever you can get clean tracks it's going to get you you know quite a bit far along on in terms of the road oh so that you're not having a keyframe it on every single frame because that's that's mind numbing and not what you want to do you want to use tracking information as much as possible so that it just simplifies your job alright so let's look at some other things you might have noticed I have a shuffle node here and the reason for that this is pretty much standard procedure for me when I am working with quick times you can see this is a a ProRes MOV file and when I look at it it automatically has a white alpha channel in it which means any rotos that I make because rotos by default are making white shapes you can see that roto did absolutely nothing right so I usually will just chuck a shuffle node after that MOV set the Alpha to black or zero and connect all my rotos in line after that so that whatever shapes I draw are now white on black okay which brings me to another another thing let's say let's say I draw shape and I'm just gonna really quickly let me go find where I can see through her hair right okay so here I've got this shape for her hair and let's say I want to punch this hole out here there's a couple different ways to do this right I would draw another Bezier something like this and when I look at it through the alpha I can go ahead and I can either change the alpha color to black or I can set the the mode of the roto shape to - right they're both gonna kind of get me the same result however suppose this shape sticks out some and I've set it to - let's take a look at the mat channel you're gonna notice that there is this weird green shape right the red mat is where it's white in the Alpha Channel and this weird sort of aqua color shape that's sticking out is where the remainder of this this - shape is sticking out so what's actually happening there right I've already set my alpha all around to zero this shape sets it to one and then this subtracts one right because the color is white I'm subtracting it I'm - in it and I'm subtracting it from both this and this so I've actually effectively set the Alpha value to negative one here and you can see when I hover my cursor if you look right down here you can see my RGB a values when I hover over here alphas one over here alpha 0 over here alpha zero however here alpha is minus 1 this is problematic because it can mess up further down the line it can it can just cause problems if you have negative or illegal values in your our alpha so a fix for this would be to throw a clamp node after this and you can see a clamp will just just lock it down so it fits between 0 & 1 in in the Alpha Channel so you don't have any illegal alpha values but the easier to me by far easier way to do this is instead of setting this to minus is you leave this as an over and you click on the color chip and you set this value to zero on the Alpha and now I've got a black shape that even if it overlaps it's not changing the underlying value it's just putting another bullet piece of black over black and it's not creating that weird little negative alpha area so those are the kind of the two differences in terms of your your options for for creating holes in your alpha shapes all right something else I want to talk about that often gets overlooked is this toolbar across the top here of the the roto pane when you are working in in your viewport so there's a bunch of buttons here that actually are really really handy so let's take a look at them one at a time first you got this little automatic key button if I uncheck this I'm now no longer in keyframing mode okay yeah I can't move these things right in order to be able to move this and actually affect the the roto shapes that has to be turned on okay the next one over is it links your feather so you may know that you've got the ability to create a feather coming off of a roto right and that's usually done with this little handle here there's actually a keyboard shortcut for it and that is e e not F I don't know why but it's e so e will extend out the feather shift e will will kill the feather right but the important bit is no matter where I've put the feather if ice now move this vertex the feather is gonna move with it right that sometimes you may not want to do that you might want the feather to extend out to there but start earlier right and so you could do this and do this but that's extra work if you just uncheck that button now I can move the vertex but the feather handle stays where I put it pretty nifty other things that are helpful when you have a shape like this that has a definite geometric shape that is shifting over time it's really really easy for particularly for newbies to introduce chatter and I'll show you what I mean let's say I were row towing her hair and I'll just do a quick roto by hand right so let's say I'm doing this sort of thing and then I go ahead or back ten frames and I do this and I keep doing that over time and eventually I have accidentally without realizing it I have introduced some chatter so the whole thing has sort of turned around which can happen right you get a complex shape and you try and match it to what's happening in reality and you've ended up kind of messing everything up and everything is sort of chattering so that as you scrub through this this thing is really changing shape and not sticking anymore because it's it's just all out of whack well the way to avoid that is to use this number button and that gives you a little idea X for each vertex so in the example of this roto if I were to turn on the number tags I can see that number eleven is always in this crease no matter where I go in the scene number eleven is going to stay there so that can help you to make sure that the shape of your roto is our gated to the shape of whatever whatever your rotoscoping right so that you're not introducing chatter eleven is not migrating its way around here and I see this a lot you know particularly with students the first time they ever do Rodo they get themselves into this this situation where they're introducing chatter because all their vertex is or vertices are sort of migrating around the perimeter of the thing they're they're keyframing so using those numbers can really help with that alright next you have the ability to turn on and off the outline not really sure what the application for that would be but if you just need to see if you really just want to focus on vertices and not on outlines you can do that I don't really see an application for it another thing would be you can turn off the individual vertices so that's the opposite right so you can turn off the vertices or you can turn off the outlines I'm not sure why you'd want to do either of those next this one hide transform okay so if I've selected this and let's say I want to move the entire thing but for whatever reason you know the transform handles are just in my way making it hard for me to see what's happening etc I can move all of them without having to see that just by turning that on off alright next hide transform on move okay so if I select this then when I move you can see it just hides it that makes it invisible when I'm moving it so again if you just don't want to see that for some reason if you want to see it when it's selected but don't want to see it while you're moving if it gets in your way let's say you're trying to move a group here and it's just kind of in your way while you're working right you might want to turn that off so it disappears when you move very handy next up toolbar constant selection when enabled clicking in empty space in the viewer will not deselect the shape they see this happen all the time where you're like trying to grab a point and maybe you're working with the mouse not with a pen or you've zoomed out too far whatever and you keep deselecting your your selection so turn that off and now when I click out here I have to actually click another mask to deselect I can't deselect by clicking in empty space I can definitely see a reason why you would want to use that now here's the one that blew my mind when I learned it and that is this guy here which is Ripple okay one of the things that drives me nuts when I am rotoscoping is finding out that oh I needed to actually extend this point out to here for whatever reason right for just because as a hole in my rotos where they overlap and and I didn't realize it and so now I have to move that and I have to go to every single keyframe and move it every single spot move it okay that's insane right what ripple does for you is me undo this stuff what ripple does for you is it lets you turn that on and then you can ripple whatever decision I make now it will ripple in whatever direction I choose with this little indicator here so right now it's set to all so if I go like this now every keyframe will have that change right now it has extended out in that direction for every single keyframe in the entire piece very very handy let me undo that the other thing is let's say it has to only go from here to the end right so I can take that make the change key from prior won't have the change key frames after will likewise change it to from start make this change keyframes before this point will have that change keyframes after will not you can also set a custom range so if you new hole appears from you know frame 300 to 400 a make that change just in that range and a wool it will fix that blew my mind when I realized that's what that did because it's such a common thing that you find you have to move one point to fix an overlap hole and it just becomes real tedious to hit every one of your key frames particularly when you have you know as many key frames as you do on something like her face right if I if I said oh I need to move this up to blend it into the top of the head or something and I have to do that on average frame yeah ripple is gonna save me a lot of work so those are some tips and tricks for roto to make you faster at this ubiquitous tool that every compositor needs to know the faster you are at roto the faster you are at compositing period most of the time when I find that I bottleneck personally on a composite it's because I have to roto and and anything I can do to speed that up any tracking planar tracking any of those tools that that help you navigate faster any of those things that make me work more quickly through my roto process that's just going to make me faster in my overall composite so hopefully that helped you guys thanks again to my patrons as you know I'm live on patreon you can find me over on patreon the link is down below thanks again to all my patrons really appreciate you guys thanks to everybody who has has commented and subscribed I feel like I've got been getting a lot of love here on YouTube I definitely wanted to shout out VFX for filmmakers they're great channel here on YouTube again I'll link them down below they published some really great tutorials and great interviews with VFX pros so check their work out that's basically it I'll be back next week and I will see you then and keep being nice to each other keep making cool

Channel: Foxtrot X-Ray founded by Paul DeNigris

Views: 42,389

Keywords: filmmaker, tutorial, visual effects, vfx, nuke, nukex, roto, rotoscope, rotoscoping, the foundry

Id: GOMhOjz1Z9c

Length: 24min 17sec (1457 seconds)

Published: Tue Jul 23 2019