All language subtitles for Nuke 102- CLASS 7- Advanced Keyer- Edge Extend Workflow_2

all right I wanna talk a little bit about

Edge Extend before we eventually get to our big work

which is gonna be using the Uber keyer

which I'm sure you're all excited to learn about

um but again

this is this is not the Uber keyer

so to speak

this is just the basic key here

I've been showing you guys

uh with some core fundamentals

which allows

you to kind of stand as we get into the bigger key here

where everything plays apart

so what I have here is an entire comp again

done with Jessica

so let's go ahead and just show you the footage

here's Jessica waving her hand

and we have that nasty light pollution there um

the whole idea of this tutorial

specifically is that we will be going over Edge extend

so this is really what this lesson is about

um using the uh

actual Gizmo Edge Extend or extended RGB

and of course

this is in here

and you can also take this with you

um to wherever you go

edge extent is the last thing you should do

after all else has failed in regards to

trying to color correct

the edges of your character via your d spill

when all else fails okay

you will go ahead and try

out what's called an edge extend

but this is secondary

not the primary fix

because this can cause artifacts

as I will show you

when you overuse it or abuse it

so it is not the end all be all because it blurs

your edges a little bit along your d spill

so be aware that it works very subtly

if you need that just extra little oomph

but it is not something that you

you know just go goofy on okay

or go ballistic on it and over abuse it

so anyway um

long story short

let me just go ahead and go through this comp

really quick

so we can kind of get an idea what's going on

it's the same setup as we had for the last lesson

we Denise it here

you can see I do a core and I

you know take the time to actually learn from this

a composing

the way you're gonna learn green screen is not by one

composite that I show you

it's you going in and practicing

your own and trying out your own because

you have to own these comps

and what I mean by that is you have to be able to

solve the problems that are gonna be so

specific to whatever shot you're creating on your own

whether you're shooting with your own footage

um or with the footage that I have provided

so be aware of that uh

that you need to own

in other words

you can't go to a manual and be like oh

I wonder what happened

um you need to figure it out and problem solve yourself

a great artist

is has a pioneer spirit of discovery

of trying new things

and also one of just

just a critical eye

one who looks at it

looks at every single

hue difference

you know on the corners and says

I'm not happy with that

I'm pushing it to the

I'm teamed level to make it look really real

I'm not gonna just let some green

spill sit in some area

and let it be

or have it not match

and also be able to take critique from other

people as well

I just wanna also preface this by saying that this is

not a perfect comp

I threw this together

so if you're gonna be

complaining about the color correction work

uh please don't

um so anyway

each artist has their own way of working by the way

you'll notice that when you work

at a studio with multiple compositors as

as you open up their comps

and you know

go in there and

you know do your part

you'll find that

everybody has a different way of working

I think I talked about this before

some people like using channel merges

others like to use

merged screens when they merge together their mats um

so there's a whole bunch of different possibilities

so let me go ahead and go into the prime at here

so you can see this is just a general primet

cleaning up the background

foreground noise

and then I come to the grade note here

play a little bit with the gamma

a little bit with the black point

and then I do on a road here

as you can see

as I slam the gamma

we're still good

and the blur

as you can see here

now I'm working off a frame 85

so if you load up this comp

I've only made this comp

work for frame 85

the rotos have not been animated

so don't be like

why am I on this frame

it looks weird

so go to frame 85

so alright the fringe mat

let's go and take a look at that

now again I had a choice between

the atypical

IBK color single

and then the daisy chain version

uh so if I take a look at the two

go ahead and put my viewer to this

and just show you

I just switch it

back and forth

you can see

in this circumstance

the version that uh

is actually

the daisy chain worked much better

so you can see here

you know I'll take a look at the

the final results of these

you can see

I still have a little

bit of hear noise here

and some little splotches here and there

through this process

but you can see

because I've gotten a closer sampling

localized of the areas

I'm getting

a heck of a better result

um in comparison to this

versus this

I'll go ahead

and show you again here

switch this back and forth you

can see here to here

see that big difference

so again sometimes the

single versus the daisy chain version of the IP k works

try both of them like I said

alright so the grade note

I went ahead and graded this 2.04

you can see there is noise down here

but if I were to click on any one of these pixels

you could see the values are below 0.5

in the alpha

and that's important because if it is then we

you know we have to crush a little bit more this area

we're gonna go ahead and take out with a rhodo mask

so you can see I've created this

mask here and blurred it

and then I went ahead and just cut that out

again I'm kind of throwing this together really quick

and then I've screened together

both the core and the fringe mat

and you can see it's filling this area in pretty nicely

maybe going a little overboard and certain areas here

um I have the quality check here

which basically floods my

actual alpha to the RGB channel

so I could switch to RGB

and now I can go back and forth between the original

and just see what I've lost or when I'm over cranking

like for instance

this might be over cranking this area of this hair

because you can see this is still semi transparent

it's coming out pretty

more opaque than it needs to

same thing here

same thing here

as you can see

this is a little overboard

but we are getting all these nice hair follicles

you know we're retaining

all of this detail and that's what you gotta

that's what you're fighting for by the way

through this whole process alright so

with that said

let's go ahead and just poke around here um

we'll jump over to our edge de spill um

I'll go ahead and just show you what

has been created here um

I've got a key mix here

uh simply because

she's gonna have the sun behind her right here

and over here is this general red complexion

and this is just me fiddling with the screen color

here and here for each one of these

independently and also

you look at the alpha bias is very high in the red

in regards to these two edge d spills

now this affects the skin tones as you fiddle with this

um making her more of a purple

people eater um

but ultimately

this is only gonna be affecting the

edge and not so much the core

remember the core as we come over here

is meant to bring back the luminance and add it back in

so we have this typical expression

we take this merge node

get our actual information for d spill

desaturate it and reapply it as a plus

so we don't lose any luminance information

as we take out the green information

and we brought it all

back to our image

and the core looks good

the skin tones are not touched

you know they look perfect

so this area

the skin tones

you can see the difference here

if I go and go back and forth

there has been some play in the actual skin tones

which is a no

no when it comes to the edge de spill

but the edge de spill is gonna be limited

via this mask here

which is our core

coming in from our core here

um and then of course

I added a stencil here where I actually

erased this area

these areas here

which are heavy in the hair

and the reason why I did that was simply because um

those areas

I want to be um

with the edge

despill the hair

specifically

so this can be an animation roto nightmare

we have to animate these rotos again

I'm on frame 85 here

just for the sake of

I didn't animate these

you can see I only have one frame

so the key mix comes in

and if we take a look at you know

it's looking kind of interesting

because it's got different colors and so forth

but in general

we have this area here a little bit brighter

because the sun will be behind her head

we copy in the alpha now

so you can see

now it's good to go

and it just needs to be pre malted

then I do some color correction

work here where I you know

just do some

general dealings with the black and white points

to kind of match them up

and then I have this roto mask here for the sun area

that I add a grade of brightening and then saturation

I bring down a little bit

so that kind of blows out the hair area

um as much as possible

and then here

I'm gonna go ahead

and for the sake of his demonstration

go ahead and disable this

this is the actual edge extend

I don't wanna turn it on yet

because I wanna show you the issue

so here's the pre malted version

we have a color

of the backing region that matches

the eventual playchai

which you can see here is the sunset

so if we take a look at that right

together with this merge and all

all this is by the way

is the sun reform added

transformed

did little bit of grading

and then I used a ramp

to bring in a little bit of the blue hue

that was lit by the actress

we actually had a blue fill light on

the front of her

so I'm trying to introduce a little

bit of that Twilight

if possible

or that bluish horizon

to kind of cheat a little bit

it is it is a hack

cheat to try to color correct your background plate

your background

image to match with your footage

unless of course

you know obviously it's

one can either dictate the other

sometimes you have to color correct to

the actual green screen

plate of the person on the green screen

and then the opposite is

the other way around

where you're actually color correcting

her to match the background

so you know

it's the background to match her

which is very rare of course

but regardless

we go ahead and just jump over here to our final merge

and it's looking really good

now we still have issues

this is where you got to come in and be critical

did you lose the gradient um in here

is it a sharp fall off

now edge blurs

are another way of kind of

softening this effect

so after the actual premult

which is right here

we can add an edge blur uh

which you don't only

you don't wanna do too much of this

maybe like one or two pixels or something

and you can see what it's gonna do

it's kind of

melding it together

now we still don't have light wrap

we don't have that awesome

um you know

a despil um

per edge region uh

plug in or whatever

or script that I'm gonna show you

which is in

the Uber here

we do not have

um you know

anything like flares or

anything like that

added again

there's nothing in here that is actually helping it

really mend to

the background just yet

you can see this

edge blur does help

a little bit

and kind of

kind of dealing with those harsh edges

but we still have

and this is where

you have to pay

attention obviously

is to come in here

and look for

halos around

your character

or black lines

around a character

you either have

one or the other

or you're gonna have nothing

in this case

this is this is pretty much

you know nothing

cause it's a highlighted color

but when you

get dark white

dark or you know

white dark white

you know what I mean

it's gonna be telling you that

you need to fix

these areas

um they could

see there is a green tinge on

her hand here

so there could be more work needed to be done

in a d spill via

hue correct Rotos

um here you

can see that this

obviously needs a lot of work um in here

but we have maintain

all these nice hair details

the background

of course use

needs some grain

and some defocus as well

which you could add

but I'm not kind of worrying about that right now

um but in general

you can see

it's looking

it's looking pretty good so

when you come to a point where you

get to issues like this okay

so if we kind of go back

and take a look at

our alpha here

it's going to

take a look

this is a heavy

heavy gradient here

so when we talk about

edge extent

edge extent

basically means

it's gonna take

and I talk to

this is like

the opposite

in the way that we

smeared the IBK in

this is actually gonna do that outwards

so if I were to

create a roto

paint note here

really quick

and let's go ahead and just look at the footage here

what this is going to do

what Edge Extend basically does is come in here

and I'll go ahead and add a smear

smear tool here

and what it's gonna do is your alpha and again

I'm only gonna fiddle with RGB here

your alpha okay

is going to be is gonna stay the same

so this is gonna stay the same

you're not gonna touch this alpha

this is a big thing in Hollywood

you do not get to change the matline of where it is

in the real world

you have to solve it on your own

so how do you do that without you know

what can you do

well you can extend the edge by

doing a blur in almost like a vector smear

of the edge here

so I am actually affecting the RGB here

I am blurring and streaking this footage

as you can see right

so let me go ahead and add a pre mold to this right

so here we are

so you can see I'm not the elf is the same

so I'm gonna go ahead and add a pre mold here

so let's go

ahead and take a look

if I take the roto pane note and turn it off and on

you see what that did

the Alpha edge has not changed

but the RGB has been smeared from a point or an edge

you get to define that edge with the edge extend

via a eroded alpha edge

so you define where the blurring starts universally

and it's doing exactly what I'm showing you here

it's smearing the edge along the normal

and it's smearing it out according to a line you define

that is distant

perpendicular to the actual surface

so you can see now

you know if I

once you have that going

I can go ahead and just

come in here and guess in this case

I'm gonna unpree mold it actually

I'll just leave it as

in here and just put it through the pipeline here

as go all the way down to the bottom here with my

cheese ball version of of

of this process

you can see

we've basically eliminated the issue

probably could use a little bit more smearing here

right so if I come in here again

and just push this in

and it's pretty pathetic what I'm doing

and it's something you don't wanna do on a final comp

cause it'll look like uh

it's seen in uh

Lord of the rings where

Frodo is in the another world

but you see what I'm talking about here

and again I can

I can have my viewer set to this viewer here

and go to this Roto paint node

and just come in here

ever so slightly

and start to pull this in

like that right

so I'm doing

I'm just showing you

not saying this is what you should do

but I'm just showing you what the edge extend does

what it technically does

it solves the problem of maintaining the edge

so we don't have that keyhole effect they talked about

but at the same time

just a little

bit of a nudge of repeating the pixels that are here

further down the line

and filling in

any weird artifact right

so you can see

it's looking good

there's no real problem over here

it's only in certain areas

usually in motion blur

and it can get very tricky here

usually I will cut out any core area

when the hand is waving

because the core

when crushed

if the hand is 100% transparent from her waving

you should have no core in this area

so I'll stencil out the core of anything

that's crazy

like for instance

with Sam Jackson

there was a part where he raised his hands

really quick

talk about the credit card

and ultimately

we had to just take that core information out

so we basically chopped off his forearms

in the core

but of course

the fringe mat was still there

and we had to go in with

a little bit of roto paint work to

bring back that alpha

so it was a lot of meticulous work

so be aware of that

so you've seen all this as is

let's go ahead and poke around

I wanna again

just show you before

I unveil the awesome

edge extend here

and how you should not abuse it

cause we're gonna show it

I'm gonna show the artifacts of it

so over here

I have this

edge extent

easy example

this is a great way of demonstrating

uh the issue

so I made this kind of like crappy little

object here

which if you can see it

it's an elephant object

it is currently

you know it is what it is

and if we take a look here

we could see

we have this

green edge here right

so you have this green edge right

and this green edge is

it is what it is right

so you can see

you know it's just

it's pretending as if this is the actual green screen

edge of an actual character

um that you would have right

usually a little light pollution there

and you wanna get rid of

so I'm just kinda

you know creating this artificially again

I could also hit unpremolt if I wish

I'm premult the image

and you can see this is

this is basically what's been created

there's nothing going on

what I think it's already unpremulted

since I'm premulted yet

so the Edge Extend and this baby

this whole little thing you

can add together

it's not very complicated

the Edge Extend itself has two options here

and I believe you can get this off of uh

Wikipedia by the way

so just look up edge extend

inside of Wikipedia

there's I think there's a whole bunch of versions

this is the control mat and this is the image

so you can see I'm plugging in the image and I'm

off shooting a filter road of the original image

and in this case I've eroded it 14 pixels

which is pretty extreme

so it's eroding back

I'm defining the line that it's going to smear okay

and I'm gonna show you

how tight little corners like this will give us issues

so you can see what's happening here

I'm eroding in

this is just defining the line

and that is the input to the control mat

as you can see here

so I'm gonna go ahead and show you what this does

so there you can see

what is going on

we've we basically

extended the line and it's streaked it across

now you're getting interesting artifacts

in these tight corners here

you see this stuff

here's where if you take the extension

further than I would say maybe 5 pixels or whatever

you're gonna start to see artifacts

you're gonna see a blurred edge around the character

so what exactly does this edge extend option have

well first thing you have to ask yourself is

the incoming image

is it UNPREE

multiplied or pre multiplied

well in our case

it is UNPREE multiplied right

so we're gonna put this to un pre multiplied

if it's pre multiplied

make sure this is set to pre multiplied

asking you you know

the incoming image coming in

what is it pre multiplied already or un pre multiplied

make sure you get that right

or else it's not gonna work correctly

so now at this edge extend

we have taken the line we've defined here

which is you know

an eroded version of the original Alpha

and we've said okay

start from here and smear out okay

so let's go and take a look

you can see what it's doing

it's starting here where we define it

and it's smearing it out

how much smeared you get

well there's a couple of controls here

which can be quite confusing

you have the vector blur slices here

again this has to do with vector information

and you can

if we come to like a say as come to this version here

again this is not pre multiplied yet

you can see the alpha is not gonna change

so ultimately

we come to the premult

we're back to where we were before

so if I take this to the grade note here and

put the premult

you can see the alpha edge has not changed

we are not allowed to change the alpha edge right

The Alpha Edge is the Alpha Edge

but we have to deal with this stuff

so what do we do

while the Edge Extend fixes it

by smearing everything in

okay so there's a couple of options here

there's a pre

pre blur control mat

you can hover over these and see what it says

blurring the control mat by a mono amount will increase

the width of the extended edge

some of these variables play in

the amount of the extension

so it's it's hard to kind of explain these

um this is the number of iterations of the vector blur

and then the

as you can see

the pre blur vector

it'll tell you in these

that it actually helps the extension

so the vector length is the biggie

and you can see just the extension itself

it's kind of pulling it more and more in

let me go and put my viewer here

so you can see the vector length is still pushing it in

right and then you have the pre vector blur

which kind of pulls it in even more right

and then you have the pre blur control

and you can see how that has a play in the pull out

so we can see here

we have a couple gradients here

if I put this down

so put this to vector blur slice to 1

you can see it only does it one time

you can do it 5

a lot of this has to do with the ghosting effect

that you would get um

in the process also

how many times does it actually slice up

how many times does it repeat

the same pixel over and again

so it has to do the distance as well

so you can see if I take the

you know vector length here

you get different results of the way you want it

and sometimes

you wanna have it more original to the original shape

and sometimes you don't

so it's basically what it is

and now you can see here

we have the output extended RGB

um you can also export vectors if you wish

and then you're gonna have to premult the image

uh here because the final output of what you

get from these edge extends is the image

but it's not officially uh

premulted back to the original Alpha

so if I premult it now

you can see what we've done

we've solved the problem

but we've introduced some

artifacts around these tight corners

doesn't look too bad here right

it's just when you get to these corners

things get a little bit goofy

and then they start to swerve a little bit too

because it's taking the information here

and using the out vector direction

uh you know

coring along the normals

if you're thinking of CG

and pushing it

out this direction

so it's not gonna push it out this direction

because it's facing this direction

this is the perpendicular direction right

so that's why you're getting these weird pixels now

on a very small

scale of this

you can get away with this

you don't want to push it too much

want to push it until you get rid of all the artifacts

and then you're good to go

so in our case

do we need to go this crazy

well let's go back to our edge extend here

and start fiddling with these controls

and see if we can find something that is

I'll see there's the green

green starting to get introduced again

so just wanna push it just enough

and then just play a little bit with your pre

blur vector and vector length

and you'll see

that you know

again it's it's

it's not a perfect deal

if you had a checkerboard image

you'd be in trouble

but if you have skin tones

it's a little bit more

if it's just one constant color

like in our actress

whether around her hairline or skinline

you're not gonna see

this differentiation

but if you did had a

some alien character with checkerboard skin

you would definitely start noticing this stuff

um so anyway

it's good and see how it looks with the final product

so here is with the sun behind it

and let's go ahead and come over here

and just disable this

here's that green line

you can see what it did

so now we're gonna see the artifacts that

approach when we overdo it in our regular comp

so I'm gonna go ahead and

take a look at this image

here we go and I'm gonna go ahead and disable

or enable this and see what we get

so we're gonna notice this around these edges here

right that I was playing with earlier

let's go ahead and enable it

and I didn't push it too much

and it helped significantly

especially in these areas

we still have this green tinge that we could either

get rid of by going into our d spill and fixing it

but you can see it worked really well

and these areas here

now you could key mix this in by the way

uh and have a mask for only certain areas

so you can actually have multiple

key mixes of different uh

different intensities of the edge extend

that are roto animated for different areas

that might be needed right

one of the things you can see it blurs the image

so here you can see is a streaky effect

here we have these define lines in the hair

and it's giving this weird streaky effect

and when you have multiple layers of semi transparent

fully transparent hair

you when you streak that image across into a direction

it's sort of

offsetting itself from the actual Alpha Edge

so you might get some very strange results

like for instance

you might get a little bit of the

the shirt color in the hair color being pushed in okay

which in this case doesn't look too bad

but you can see how

it can start infiltrating those areas

so you can see here

it's I mean

it's not too bad but you

somebody might pick up on that

it might go away

and why is the hair

you know what is this all about here right

so that's why you might isolate this to

an edge that has no hair in it okay

so you can do that with rotos and key mixes

as I described earlier

key mixes go crazy with those things

I'm telling you um

uh you can see here again

weird artifacts

you'll get this blurry edge

you see we've lost the granularity

so you can see here

uh this is this

and this is that

and you can actually come in using a edge detect

if you wish

on your Alpha Edge

try to reintroduce or regrain this image

if you prefer

if you find that this is too much

so you're actually adding

a regraining of the area that has been blurred

so just keep in mind

you've actually blurred your image

so any grain

even though this image might be most CG

nowadays I'm sorry

most green screen stuff

there's two different methodologies

one is take your stuff that

you were shot on a green screen

degrain it all

still there's no grain

even in the RGB channel

RGB channel um

and then regain everything at the end

when the CGS added

simply because the continuity is a little more straight

on whereas some people are purists

and they want you to match

the grain of the back of

the foreground plate of the actor

to the back

have the background plate match the foreground plate

which is more difficult in which

and in this case would actually involve

using an edge detect to come in here and only isolate

the edges of his character that have been blurred to re

add green um

to those specific areas

so it can get really fishy

when it comes to the edge extend

just be aware of the pot

the many different possibilities of this and again

we haven't solved the problem completely here

I can over crank this like crazy if I wish right

so I go nuts

let's go and just crank some of this stuff up

I'm gonna try to get rid of all that green

tinge right

this also depends on the filter road

so if again

if I come to this filter road

this is the edge I'm extending

I can also come in here if I wish

and harden up this edge

so if I hit the grade node

but this to alpha

I can actually say okay

let's go ahead and take the black point

pull this down

I could also play with the gamma a little bit

pull that in so again

I'm redefining that

edge because blurred edges

are gonna be tricky

so now if I come back in here

take a look what

we have now

now you can see

if I take this grade note and disable it

it's actually

readjusted the defining edge that gets smeared out

but here is a perfect example

of where you're getting blurry edges

so again you can see the issues that we have here uh

again this streaking ability

and again if you come into this edge extent

it's an interesting thing

if we start this back down to like

we'll put this back down to like say one here right

uh we'll put this

everything basically down really low here

right so you have the vector length and all this

so you can see by increasing the vector

let me just go and bring these up a little bit

Vector Blur Slice

can see how it's sort of almost in a

I would say log rhythmic fall off

how it's kind of spreading out the extension

it's a repeat of the last pixel

so you can see right here

it would take this pixel and repeat it

so there's a blurring and a repeating of the pixel

as we kind of move across the vectors here

so let me just go ahead and just kind of

give it a little bit more pre blur there

so again the artifacts are evident here in the hair

right come over here

it's just like

look at that right

and not too bad here

because this is all one consistent color right

when you get into issues

here here's where you're getting her actual shirt

uh infiltrating

and I'll go ahead and disable and re enable this

you can see what's happening

it's taking this line here

smearing it out and causing this issue

and then here's the skin tone

getting infected into the hair

almost like the hair's been cut off here

so it is tricky

and this is where you would involve max masks

so for instance

you could come in here

and just create a key mix like so

and I'll just go ahead and plug this in

actually this will be the A

this will be the B

I'll just go ahead and make an extension here

and we're gonna go ahead and create a

roto and we'll plug that in obviously add a blur

don't wanna do anything without them

blurs on them rotos

and we'll just come in here and choose

the areas that we want this to effect so

let's say if I come in here and choose this area here

and this area here again

these rotos can be tracked in or manually

uh animated

um throughout the process

so even like right here is fine

see bring this up here

the whole hand actually is one is not too bad

it's good kind of this is a seagull by the way

if you're curious

so I'm just kind of

kind of you know

just coming in here and you know

I could just you know even extend this

off into this

make this one whole roto if I want

but you can kind of

get the idea of what's going on here that way

the hair is left to itself and it's not being affected

and if I still have issues

like for instance down here

this is actually just

the highlight of the light hitting her

so it's not technically bad

but I'm again

if you wanted to deal with this area

it's gonna be very hard to come in here

and add this part of the key key mix

um because it's gonna start to affect this area here

but you could do it um again

there are many different ways

you can always

like I said

the first priority

come back to your edge here

go to your edge d spill and look to see

if you can isolate that area

so if I come to the mix of the core in the edge here

you can see that

this Halo could be

like blue pixels that need some work or something

um that be caught

be causing that but again

first priority

and then last case scenario desperate

but very subtle edge extent