All language subtitles for nuk231-class03

hello and welcome back to nuke 2 3

1 nuke compositing best practices

this is Victor Perez

and this week

we are going to start by analyzing

the issues of masking

masking by definition

is the application of a mat

but in this case

is allocated in the alpha of this rotonaude

and is delimitating the area

we want to apply the operation of this note

through the main input

so in this instance

I'm applying the mask through the mask input

but there are other ways to apply this mask

and also things can be complicated

when you apply the same mask through different nodes

okay so in this case

is the regular version of the masking

and that in this instance

I got a great

but any note that is having this mask input

can use this feature

but not only

you can apply the masking also to other notes

by using a work around

okay that saying work around must be used

when you are using the same mask for different notes

in the earliest versions of nuke

this mask input wasn't there

so the option to apply a mask through a node

was by using the multi channel feature of nuke

this was coming way later okay

and it was a feature request from many users

coming from shake and other software

that were already using their mask input

okay so this is a classic case scenario

you have when you are camping

okay this is what is called an explicit mask

we're going to distinguishing here

between explicit and implicit

when I'm talking about explicit

it means that the mask input is being used

so you have the graphical representation in here

that is telling you

this note is being applied here

through this input

so you have a practical view of the organic gram

of how this mask is being applied to the note

sometimes this case scenario

is going to be useful

to understand what's going on in your script

but some other times

is going to be tricky

just to apply the mask from the outside

when you are applying

certain modifications or combinations

to your image

okay so this case is the explicit mask okay

then you have the same

same result

with this implicit mask

so let's analyze the difference between those two

because there is no right or wrong in this case

they are both right

but in this case

my mat here

is just been traveling in a parallel basis okay

which means I can process this mask

and I'm using

does the RGBA set of channel

so in case I want to analyze

what's the alpha here

and what's the alpha here

I don't need to go through other channel sets okay

that's good

here the practical theme is

you don't need to get

other branches

in this little tree

so what if I want to apply

transformation

after my roto has been done

in that case

imagine that

of course I can do this

but imagine that

by some reason

I want to apply this transformation

before the great

or before the effect

remember that this great

is just representing an operation

random operation

okay so there are other operations

that you might need

to be applied after the transformation or maybe

because you have already a transformation in here

you don't want to break the concarcination

we were talking about in the previous class

so in this case

it would be way better

just to apply this transformation in here

but what happens

that I need to apply this transformation

also to this rotor

so of course

I can clone this

and apply here a clone

I called the clone

by selecting the notes

and pressing Alt K

okay so here

I'm doing exactly the same transformation

to my main image

and to the mats okay

but as you can imagine

this is kind of a double process

okay is again

is using clones

that some people

doesn't feel that comfortable

because they were creating

issues in the past

so you can use this for transformation

but in this case

if you apply the transformation in here

everything is going to be

way easier okay

so in this case

the transformation this

applying this

translation

or rotation

or any other operation

you want inside

to all channels

coming through

the main input of the transform

what if in this case

we have the other way

around imagine that

I mentioned before

that I have already

here a transform

so what if I put

a transforming here

and I did my rotor

after the transform

in this case

of course I'm breaking the concatenation

so what I need to do is

I need to split this

and then apply

the double transformation

so again the cloning

and then reformatting

just to call

the same mask in here

so what I was doing

is emulating this

the important thing is

when you can get

lesser strings here

for instance

is way better

just to use

one single string

okay here is not wrong

but believe me

nuke is going to be way faster

processing these

because everything is coming from

one single stream

okay I'm not talking about

dramatic times

but is always better

that architecture

of the software

has been designed to work in

a single stream

okay so just to let you know

in here the way of

selecting the

the mask is going here

in this mask knob

and then selecting

from the incoming image

what's the channel

I want to select

okay here I have

all other channels

by the way what's the difference

between having

the channels in here

and having the channels in this

other channels

well the main difference is that

the channels

you are list in here

in this main

pop up window

is the list of

available channels

for this image

you are analyzing

in this particular note

while the other channels

is telling me that

all those channels in here

are available

in the script

but not available

in this particular image

okay so they are

the layer sets

and layers themselves

that are being used

for this script

to be processed

so in case you

are using copying

or other channel manipulators

you can use

those channels already

without the need

to create a new

layer sets okay

so in this case

I select the mask

so what's the way of

applying this

roto through the same

stream well

what I did is

exactly the same spline

but in this option

what I did is

in the output

instead of leaving

the default alpha

what I did is

using the mask

channel okay

so of course

I can use any other channel I prefer

you can even create

your own channel

and then call it

for instance

Roto okay and

then in here

you can name

the channels

after the area

they are rotating

so for instance

you can called in here

for instance leaps

okay you can

of course create

the default

four channel sets

okay that red

green and blue

but if you want to create just

one single mat

is way better

that you put

the name okay

so leaps so

here now is

because my grade is missing

the mask input

so what I'm doing

is I create

a new layer set

that is called Roto

and in there

there is one

single channel

that is called leaps

see that they

color of that channel

is red is because

nuke every time

you are using

one of the channels

for an entire layer set

what is doing

is selecting

the first available

RGBA channel

which is the R

the red one okay

so if I go in here

a nice select

my roto layer set

the color of my lips

is going to be red

but not because

this is mean to be

red is because

the information

is allocated

in the first

available channel

okay and this is happening

even for multipass

layers of uh CG

so once I have my layer

that in here

has been a custom

made layer set

I go to the great

and then I select

the mask leaps

I like to use

this feature

of naming the areas

because it's going to be way easier

when you have

multiple mats

traveling around the

the streams

okay so then

this mat is

going to be available

not only for this great

but also after this great

so in case I want to shuffle out that channel

I just put it in here

then Roto and is telling me the first letter

of the name of that particular channel

that in this case is L for lips

okay and you see

this is still here

so in case I want to apply

that marked for other purposes

like primotuplication or other things

I can still use it um

talking about primotuplication

you can pre multiply this image that you have in here

Marcy with this okay

um by doing that

you can apply the primal

and here is multiplying the RGB

by the channel of my choice

that by the fold is the alpha

because it's the natural channel for transparency and

and stuff but I can use also this

okay so in this case

I'm doing the premotification by the same mask

but let me tell you

this is wrong

because I'm applying an effect through a mask

and then premotifying that by the same mask

so that is going to create issues in the edges

so instead of doing this

if you prefer

you can use this other warflow

so I'm going to reverse the order of my notes

so what I am going to do is press command or control

and then the arrows of direction

I'm going to press up if I want to move my note up

okay in this case

as you can see I'm moving

with the arrow up and down

okay so you can swap the position of a certain note

okay so in here

what I need to do is to promote apply

and then using this image to apply the grade

and then instead of using the mask

I'm going to use the primal duplication

by that particular

okay channel

the only problem in here is this image has no alpha

and this is because when I was pre multiplying

this image already has no alpha

of course you can do two things

you can apply here the RGBA

and then here generates an alpha by clicking Alto Alpha

Alto Alpha is going to create a white alpha

for every image that has no alpha channel

and remember

every image that has no alpha channel

because there are certain images

that have an black alpha

and that means that the image has an alpha

the only problem is that alpha is black

so in here to this

how to alpha to work

you need to have just the three okay

not the white rectangle

okay so in this case

what I did is apply my mat in here

then I premotify

and then in the premotify

I apply also the alpha

but if you don't want to apply that work around

or maybe because you are not interesting

in having that white alpha in there for any reason

what you can do is you can use this

then apply the correction using the primitiveligation

and now what I'm going to do

is I'm going to use the shuffle note

just to get in my alpha

these lips matte I create

so what I want is to preserve the RG

and B from the RGBA set

but then the alpha is coming from another set

so I'm going to use this second column

so I'm going to call my rotor

and then I'm going to say that

the alpha is coming from this layer set okay

so now I have this alpha okay

so this is in case I want to multiply this uh

mat for any reason okay

and as you can see here

this is possible

because I have this implicit mask already working here

it was a bit tricky

if I wanted to do it with the explicit

of course there is always a way

but what I'm trying to show you here is

what's the fastest way

or what's the smartest way

or what's the optimal in terms of calculations

okay so in here

you have the two ways for explicit and implicit mask

and we are going to use this concept

a lot through the next two classes okay

so it's going to change massively

the way you are applying mask and other processes

let's move ahead now

and let's have a look at the issue of double masking

so in here what I'm doing is applying a great

through an explicit mask

and that's okay

but the problem is

if I apply again the same mask to another note

the effect that I'm doing in here

is the same as a double pro multiplication

because actually

I'm applying twice the same mat

to promote apply an effect

because the pro multiplication

needs to be applied always

just once remember

never more than once

because it's creating issues in the edge probably

that tiny issue is going to be quite difficult to see

but in certain circumstances of high contrast

that particular edge can be held

um if you're not aware of

how the promote application of the effects are working

probably you're going to spend a lot of time um

maybe not the right way

to fix that issue

okay so this

is completely wrong

okay so how can I apply this mass through both effects

well you need to group those effects

as they were a chain of effects

remember the concept of concacination

okay so in order to do that

what I'm going to do is

I'm going to apply a separate process in here

and then the first one is just creating the pinky lips

and the second is darkening everything

okay so what I'm doing is

I apply my mat

through a key mix

so whatever is inside the mat

is being used from the a input

whatever is outside is going to be

from the B input

in this case

you are applying one mask

for one chain of processes okay

let's have a look at the difference between this

and this

can you see the difference

in this particular case

is quite gentle

and probably is not going to be that wrong

but believe me

it's not the right way of applying the effect

and sometimes

it's just getting unknown for the realistic result

so be very very careful when you are applying mask

okay and this is the most complex case scenario

for the masking which is using implicit masks

but applying them through a chain of effects

or operations okay

so with this

I can use the transform feature

I show you before

and here what I'm doing is I'm splitting my mat

after the transformation

I'm plugging inside my Chemix

and then applying the chain of operations okay

and this mat

can be applied for any other processes you have

by placing those operations in here okay

another thing to keeping consideration

is that that mask I put in here

is traveling still through the Chemics

so if I put in here my mask

I'm still having that mask available okay

um what happen if I want to get this mat available

but I'm using the explicit way

so the one that the mask is coming from the mask input

and not in the same mainstream

well let's go back to the first instance

so I'm going to delete that

and in here

I'm applying my effect okay

as you can see

but then if you want to get your mask to trouble now

through the main input

you need to go to an option of the mask in here

and click this inject

what you are doing is injecting this mask

through the main input

okay the source

so if I view in here my channels

as you can see

there is no mask okay

but as soon as I press inject

now in here

you have this mask available

okay so now

from this point

my mask is traveling in an implicit way

this is a hybrid

you are using an implicit method

to create an implicit stream okay

so that is the inject option

so as you can see

this is something quite easy to respect

when you are using the mask

but you can easily

get something wrong when you are using over processing

or simply getting a double per multiplication issue

okay so let's apply that now to the CG world

because usually

the CG is coming using many

many channels

and it's something that is getting quite popular now

to get one file containing all the channels

because before

it was tricky to get everything in one single file

because if something goes wrong in one single layer

you have to Bing everything

and then re render everything

just because of one single layer

since open the

XR 2.0 has been released

one of the most critical features of that

is that you can access an open the XR file

and then replace just one single layer

of the whole layer sets

that you have available in the file

so with that

you can get everything in one file

without the uncomfortable issue

of re rendering everything

just because one layer went wrong

so is quite tidy

just to get everything in one file

but you know

is not crucial

or is not better

is just easier

just to manipulate

when you are working

transferring files

just to get everything in one single file done

having 300 files for one single frame

okay so in this case

let's have a look at how many layers I have in here

so I'm going to use my layer

contour sheet

is going to the RGBA

okay so I'm going to show the names

I'm going to center and here you are

I have all those layers available okay

so what's the point of using

now the implicit and explicit

well as you can see

using all those channels is going to massively change

the way I'm going to distribute my notes in the script

so if I want to apply an explicit mask

for a certain feature of the image

imagine that I want to use

for instance

this hand okay

and I want to apply this great

I can always use the great

using the mass that in here

and using this mat from the Alpha okay

so I can change the aspect of that by using the

the great with the classic mask

but you can also use the implicit way in here

and then just select what's the layer

okay in this case is object ID

and then I'm going to use this alpha channel

that is the one storing that part of interest

okay so look at the difference

the difference is in here

you have a graphical representation of what's going on

in here you have to read what is happening here

so you are applying a correction through the RGB

and then using the inversion

which is the sign here

of the channel alpha within the layer

set object ID

and this is an implicit mask

is telling me this batch that I have inside my note

so is this better than this

no I cannot say that

but in here

you're going to get more notes

in here you have a contract version okay

so with these

you have to pay more attention to labeling in here

you can just get things rolling through the view

of the script

okay I will say this is smarter

because you are using less notes

and that is always something good

because you are storing less memory in your script

but is not something that is going to change your life

if you use this for one channel

but if you are using 30 mask

using the explicit method is going to be quite big

while using the implicit method

is just going to have a very tidy structure of masking

so then when you are applying certain operations

for secondary color corrections

that is this kind of isolation of one element

you can just apply for the whole chain of elements

one backdrop

so for instance

color corrections

and I can apply secondary color corrections okay

so all the color corrections you are applying for this

process can be in there

okay so yeah

is this going to be massively clear

that you are using the explicit way

well to be honest with you

not that much

because if I have a look at this image like this

with all those colours and stuff

actually the only channel I'm using

is the only one that is not been displaying in the RGB

so at the end of the day

if I want to understand what's the mat I'm using

I need to go in here

and then I going to the alpha channel

and then I'm going to discover that this mask

but is this invert

so I need to go in here

and then see how okay

I press the invert

because there is no graphical representation

for this invert of the mask in here

so if you want to be really

really explicit

you need to place in here

they invert okay

and then deactivate

of course they invert in here

so this is going to be a real case scenario for

splicit my mask

but this is over processing

because now I'm doing an operation

even if it's a very silly

fast operation

but I'm doing an unnecessary operation

so in here my nice thing is

I can read what's going on in this great

just by understanding this batch

and then seeing what's going on in my masking

okay so I would prefer

from those two

this option okay

another thing that can be good

when you are using an implicit way of masking

is just to specify what area

you are correcting

so for instance

you can say

left and uh

color correction okay

so with this

you can specify what's the area you are correcting

if the object ID

or the logo you are using for

the channel

masking is not specifying

as we did in the previous example of the leaps

okay and here is just a genetic object ID channel

and is using the alpha

but I don't know what's the alpha containing

okay so in here

you can just say

left hand okay

so when you are using the CG

this can save a lot of time

um many many nodes

that as you can imagine

when you are camping multipass

and you have plenty of passes

you can just get a massive script

okay and remember

when we are compositing

there is no award for crashing the computer

because you are using

more node than anybody else

actually a winner is someone that is using fewer nodes

for the same process

still representing the same quality

okay that is optimization

so that's all for this week

if you have any comments

questions or suggestions

feel free to post them in the forums

as always I will reply as soon as possible

this has been Victor Perez for FX PhD

thanks for watching