All language subtitles for nuk231-class05

hello and welcome back to nuke 2 3 1

nuke compositing best practices

this is Victor Perez

and in this 5th class

we are going to finish

the subject of optimization of the workflow

and remember that all the files for this class

and the previews the No. 4

are already contained in the class files

for class No. 3

so another thing that we have to discuss

is the issue of the boundary box

because it's something Misty

that I understand for many people

how the boundary box needs to be handle

okay so I'm using to start

this shape okay

is a star that is partially inside the format

and partially outside the format okay

so when you are working with the Roto

note the Roto has the ability to clip the boundary box

that by the way

the boundary box is nothing more and nothing less

than the active area of an image

so when you are applying a process to that image

is not going to be apply across the format

but across the boundary box

so all pixels inside this line okay

are going to be processed

and the boundary box

is defined by two sets of coordinates

the first one

which is the lower left corner

and then the second

which is the upper right corner

so in this diagonal

is just telling me

what's the area of action that is going to be apply

okay so that's the boundary box

but 50 notes like

the rotor is affecting how the boundary box is behaving

for instance

I'm going to apply here square

so I'm applying this shape okay

and see that my boundary box is now expanding

inside the format but

I'm clipping the boundary box to the format in here

which means in my previous image

the boundary box was even outside the format in here

as soon as I clip to the format

everything that is going to be

created by a spline in here

is going to be limit to the inside area of my format

the format is representing the pictures

that are going to be display in the final image okay

so I just clip

see the difference in here

I apply also a circle

see that the circle is supposed to be outside

but see that

the boundary box is not getting outside the format

which means that is nothing outside

so if I transform that

see that the boundary box is travelling

with the transform okay

but all areas that wear outside the formats

are now crop

okay because I was clipping my boundary box

if I deactivate those rotor nodes

see that my star that was clipped by the roto

is now reappearing as a whole

okay so what is happening here is the clip to format

is just cropping the image outside the format

and they are five options in here

which is no clip

boundary box

the format the one that we just review

and then we have the union

of the boundary box and the format

or the intersection between the boundary box

and the format

okay we are going to analyze all of them in here

so the first option is the clip to format

okay and it's not grown

it's just you need to know if you are going to need

that extra space

that you are having your image or not in here

if I was going to transform probably

I want to get everything from my original image

and even from the elements I'm placing okay

because everything from this note is going to be clip

okay so this is the first option

then we have the second option

which is this note is clipping to the format

but this one is not

because I just plays the no clip

so what's happening here well

see that we have to analyze the pipe from the region

so in here I have my boundary box

that's related to the whole image of my star

but then in this is having the clipped format

so exactly as before

so I'm getting my square in here

which is inside the format

but outside the star is just gone okay

but in the second row to note

I just say that I have no clip

so when I'm applying this circle

my circle is getting even outside the format

if I transform that

you will notice that the difference between this

and this is that the circle

is complete

okay I'm not clipping anything

but there is also another thing

have a look at my star

oh what's going on in here well

what is going on is a particular feature of nuke

that is the extension of the last pixel

of the boundary box

this is something quite common

and actually

every time we are using a transform

that issue is being addressed by this black outside

because nuke

every time you are getting an image touching that

boundary box

or by default

the format is going to extend automatically

the last pixel that is touching the boundary box

or the format to the infinite

but is not being processed

is just a way of displaying the image

so if I do this

and I clip with this boundary box

this image and then I move

what I'm actually displaying here is my boundary box

was clipping this part

and now everything is getting extended up to the end

and see that right now

the last pixel that is touching the boundary box

is actually black

so now it's extending black

of course extending black is like

having nothing beyond the boundary box

but is not having nothing

is actually

in the correct way of analyzing the image

is extending

constant black value

so zero value

if we go to another example

what I have is that

the square is having the intersection between

the boundary box and the format

so here have a look

what is going on

see the boundary box

the last pixel in there

is this one

so is touching the boundary box

so then it's extending that pixel horizontally

to the infinite

and then the same in here

so it's not like the square is bigger or is broken

is just totally normal okay

but we're going to see this operation in a bit

let's continue with this

because as I mention

what I'm doing is extending this black pixel

but who is in charge of deciding

why I'm putting in here this black pixel

where by default

the transform

is just preventing you to have that extension

that is quite ugly

when you are transforming an image

so he's adding a black pixel

in the last pixel of your shape

so if I remove that

see that now the boundary box is just shrinking

well it's not shrinking

is that in the black outside option

is extending by one black pixel okay

so this is the natural image without the black outside

so everything that is touching

the edge of the boundary box is getting extended

so in order to prevent that

by the fault they transform

is getting this black outside

so why is this extension appearing then

well is because when we are cutting my boundary box off

beyond the format

with the first operation

this is now touching my boundary box

and in here

with this circle

I'm extending the boundary box

because in here

I'm not clipping in the second note

and not clipping the shape of the circle

so what is happening in here

is extending this last pixel from here to there

and now this is the final boundary box

so that's why

when you are moving

you are getting this piece

that is representing that area

that is from the edge of the format

to the edge of the boundary box okay

so what if I don't want to have that

what if I want that to be completely crop

without extension

well you have to use

now in here

a note that is black outside

if you place the black outside in here

what you are going to do is just to prevent

after this result

to have my last pixel to touch the edge

in this case

of the format

so by adding the black outside

what I'm doing is just adding a pixel

to the boundary box in all directions

so is to the right

to the left

up and down okay

so is extending that boundary box with a black value

so now when you are applying the circle

and then you are moving

the circle is complete

the star is clipped

but you are not getting the extension of the pixels

okay so that's why you need the black outside

so every time

you are getting funky results of extensions

from the lax pixel touching the boundary box originally

this is the note that is going to help you

okay so I'm going to leave it in here for you to study

then we have the best case scenario

when you don't want to lose a pixel

of your original image

this is recommended

when you are using tracking operations

or any transformation

that is going to use pixels from outside the format

okay so in here

what you need to use

is the option no clip

that is the same option I was using for the sequel

so that is just going to add information

but never touch the original information

that you already have in your input image

okay so in here

I'm adding the same thing

so if I transform

I have everything together

okay and nothing lost

and see that the boundary box is traveling

every time I'm moving the transformation

and more than that

every time you are using a note

that is processing the image

and is expanding that process

like for instance the blur

if I'm blurring now this image

see that the boundary box

is getting bigger and bigger okay

but in here

is being crop

at the format why

well it's because

I'm saying in here

that I want to crop to the format

but not the input

just the effect

okay so if I use the blur

is going to preserve my original boundary box

but is not going to expand the boundary box

of the effect

beyond the format

if you don't

want to crop to the format

you just deselect that

and then everything is going to expand

to all pixels needed to

to the operations

now in here

we have the B box

b box is just going to add the information you want

but is not going to modify

the original boundary box of your image

so if your image is inside the boundary box

is all good

if your image

that you are generating

the mat or the shape

is touching the wondering box

as I mentioned before

is going to expand

okay so if I apply now

the transform

look what's happening

he's now removing that

extension effect

why is because

the boundary box is actually the same as before

so I'm just adding the black outside

to this original boundary box

and then if I use the boundary box crop A9

placing an element

outside the boundary box

that element is not going to be display

so is not in the

available area

to be represented

okay so that is the boundary box

so you have to pay attention

when you are using that

then you have

the intersection

between the boundary box

and the format

and this is the most restrictive way

of working with the boundary box

which means

whatever you place in here

in this rotor

needs to be

inside the format

and inside the

boundary box

of my previous

and everything that is getting outside the format

and outside

the boundary box

is not going to be

represented

okay so he's cropping

my boundary box

and he's not extending

the boundary box

so that is the intersection the same

if I apply the circle in here

outside the boundary box

nothing happens okay

same issue

of the black outside from the B box

but in this case

we don't have the outside area of the format

then we have the intersection

so they're saying as before and then they clip to known

and this is a curious case

because in here I was expanding my pixels up to the end

and now I'm deciding to place a certain element

so if I transforming here

or simply I apply a black outside

the blue extension of my rectangle is being preserved

because in here

this circle

is just expanding that boundary box with that extension

okay so this is the original image

this is now my circle

this is now my image with the black outside okay

so this is something to be careful okay

so I leave that

and then for the last one

I'm going to get the B box and the format

just to get the outside area of this square

so if I move

in here see that the square is actually a bit bigger

but not much is just up to the area of my star

so it's not expanding more than the pixels

that are inside the boundary box of the original

but it's expanding within the limits of the format

so that's why everything

like the circle or the square in there

is being expand normally

okay so that is the transform

then I prepare for you

a few examples of optimization of the boundary box

so in here I just apply an scale operation

so if you are sure that you don't need

those pixels anymore

you can just crop them

so by applying a crop

you are just deleting all the pixels

that are outside the limits of the crop

that by default

if you select a crop while uh

the last note of your composition

where you want to apply the crop

is selected

the crop is automatically setting the limit

to the format of that image

so in here I'm optimizing my image

by removing any unuseful data that I have

then in here

you have this boundary box

and then you can apply the same principle

but you discovered that is not that good

so if my boundary box is getting outside

but it's smaller than the format

if you apply a crop to that image

yeah you get everything outside the boundary box gone

but you are getting also

the boundary box that was smaller here

is now expanding to the limits of the format

so for this particular example

where the boundary box is not bigger than the format

in all sides

is not a good idea

just to crop that tiny effect

so how can I apply that well

let me give you a work around

and for that

I'm going to apply a roto note

and this roto note is going to be applied to modify

the boundary box of the image

not to create any shape

so what I'm doing is

I'm going to use the intersect B box and format

and I'm going to place any shape of my choice in there

okay um why is

because if you don't place any shape

the rotor is not going to apply

any process to the image

so you can just do any shape outside I can hear

and as soon as you place it

is going to apply the process of the boundary box

of course because I'm outside the format

and the original boundary box

this shape is just doing nothing

but even more

if you want to apply that square and

you are not sure where this boundary box is traveling

you can just place it in here

there's nothing wrong with that

of course if you place it

and then this boundary box is moving in there

or by chance

you get in that

what is happening is

you are going to render something

but if you put the output at no

whatever is the shape you are placing here

is going to be irrelevant

because you are not outputting any data from this note

so is just taking in consideration

the boundary box work

okay so when you are cropping an area

that is smaller than the format

probably is going to be better

yes to use the roto

and of course

you can use the roto also for the other one okay

then when you are handling the boundary box

sometimes is going to be helpful

just understand how the merge

is going to handle your boundary box

because if you have a big image

with a big boundary box

and then a smaller image

then by the fault

the merch is not going to discard any information

and that's good

but sometimes

we don't need that information

that is outside the bone

that is of my format

so for that purpose

is going to be a good option

yes to select

what's the right size of the boundary box

let me tell you that

most of the times

when you don't want the

boundary box to be beyond the edge

of the format

you want to use the P

if you are using the methodology I am giving you

for the composition

where the B input is always the main input

when you are using the B

here in the set boundary box B

the B is usually representing

the live action plate

and of course

the live action

or the background

is the base

for my image

I'm not going to remove that

so what I want is

just to preserve that format

so when you want to

keep the original format

and you are working with the be input

as the main input

what you want

is just to put in here

that you want to set

the boundary box

to the being put

so the original main image

okay of course

there are other options

like the intersection

where is just going to get

whatever is

between the format

and the boundary box

I already have

in my images

so is just the smaller

option possible

and then the a input

which is just preserving

every aspect

of the a image

except exchange

occasions where

your operation is not reversible

and you want

the particular

format to be

in the a input

you are not going to use the a

options much

and then the intersection

of course is going to generate

most of the times

this issue of the edge

so is probably going to be

accompanied by

the black outside

okay um the

most common

are the default union

or if you want to get

your boundary box optimized

instead of using any cropping option

you just leave that

to the merch

operation okay

then another thing that we can analyze is the outcrop

what's an outcrop

well outcrop is something that is going to be apply

just to reduce the active area of an image

to the area of interest

so if you are getting this image

where everything is black outside the alphabet

everything is being used

if you want to reduce the process of calculations

what you are going to do is just to apply a curve tool

to out of crop that area

so how is the out of crop working

well you are telling in here in the curve type

okay that you want to apply a now to prop

and by the way

the curve tool is in the first menu here okay

and then you are telling the outer crop

what's the base colour to look at to be crop

so if you put zero

he's just going to look for the zero value

and everything

that is going to be a block of zero value

that is useless outside a square

defining what is a possible boundary box of this image

something that could be something like that

for instance okay

something like that area um

is going to be like

taking out of consideration those values

then there is an intensity range

this is in case you are having values above or below

and you want to say

I want a threshold of 1

this amount

just to get everything that is from 0 to 0.1

and minus 0.1

is going to be take in the calculations to be removed

okay so in here

this is not actually that good

because you are actually deleting certain information

but in case you are sure of what you are doing

or in case you are getting artifacts for compression

or other kind of grain

maybe this is going to help

but remember

you are actually deleting information of your image

the outer crop is working great with CG

um why in this case

I'm not getting

the area of interest in the boundary box

is because even if in this image

is looking like

this is black outside

the area of the monster is not like that

because there are other channels in here

like for instance death

that is having values

so when you're working with the outer crop

the outer crop is going to look up

every single value of every single layer set so

is making sure that you are not losing any information

so like in this instance

if you want to apply the outer crop

you need to be sure that all the images

that you are going to crop

and it can crop in animation

that that's the nice thing

everything is going to be

with a value of your choice in here usually 0

and that is going to crop the image

even if the image is going to be in movement

so for that

I'm going to select the

out of crop

0 and 0 yes

don't look at the others

except the region of interest

that you need to be sure

that is matching the format of your image

just to be sure you're not losing any information

and then you press go

it's going to ask you for the frame range

you want to calculate

that auto crop

it's going to be right

the whole theme

so I'm going to

pressing here

is going to take a

few seconds

is not that slow

to be honest

and now is giving me certain information

that by the fall

is not display

but is in there

you just need to go to this outcrop data

and is telling you that

in each frame

that's the area that the crop should be applying

but right now this is not applying anything

this is just telling you where the crop should be

applying for every frame

so you need to create

now I'm going to copy in here the animation

and now I'm going to create a crop

and in this area I'm going to paste the information

so now if I close that

see that the boundary box is matching perfectly

the shape of the monster okay

but what if I apply this to the other option in here

even if he's looking right

and actually removing information that is useful

so if I go now to the layer contact sheet

see that now the ambient occlusion is being crop

the death is being crop

and this is being crop

so the boundary box is not

storing the information just for the rgba

this is storing the information for

any channel contain in this stream of images

okay so in this file

for instance

is having information beyond the

zero value of the alpha okay

so that's why it's not right to apply that in there

so I'm going to leave in here

and I'm going to deactivate then

the last case scenario for today

is the handling of the boundary box

when we are working with a 3D setup

in terms of camera reaction

so there are four main areas to look

when we are working with the boundary box

which is the geometry

the scanline render

the lens distortion

and the final merch

okay so where some looking here

the result so

what I'm doing is I'm applying a patch over here okay

and let's have a look at the area of the boundary box

by default is giving me this area

which is not that great

um why is that big

well the area that I'm applying for the projection

is this one

okay but this one is actually just the patch

even if I crop this

doing this

is this going to change my results

absolutely not

because it's not depending on the pixels

see the crop is irrelevant in here

the projection is actually looking at all pixels

of the geometry

so when you are applying a projection

you just need to be careful

that the surface of the projection

is enough to cover the patch

but not so big that is adding a ridiculous amount

of boundary box bleeding

so what you can do is just trimming your geometry

be careful not be so close to the edge

because probably in the representation of the 3D

that is not perfect

render is just a proxy

render for you to visualizing the viewer

is not giving you probably the anti alias options okay

so just leave a

reasonable amount of geometry for the projection

okay so now with this

I'm getting way less okay

other things to look at is

the scanline render why

let me show you the frame of the prediction

which is 153

something happens that 13 elements of the render

after the scanline render

are so close to the view port of the camera

that is actually touching the edge of the frame

I'm going to place in here a cone

trucking Kong

I'm going to convert it into a group so you can open it

and I'm going to place it in here

I'm going to put an axis

so I can move it

and I'm going to put it in here for instance okay

and in here

okay nice I got my comb represented but now

if I go to this calendar is looking perfect

but after this calendar

there is an operation

that is taking pixels from the outside

and taking inside

is exactly what is happening

when I'm calculating my camera

okay so I'm applying the men's distortion

so my pixels are getting stretch on the corners

just to represent the same amount of distortion okay

so through this process of camera projection

that bleeding

so the area that is outside the format is gone

he's not there anymore

so when I'm applying the lenses

torsion the lenses

torsion note

he's expecting me to have those pixels outside

just to put them inside again

he's like putting those notes together in here

see this is getting my pixel outside

then my pixels inside

then everything is is nice

but if I apply a crop

just by removing those pixels

see what's going on

everything that was supposed to be from here in outside

the image is gone

so I'm actually

needing more information from this scanline render

and to correct that

you need to go here

in the scanline render to the overscan

okay in the overscan

what you are doing is actually rendering the pictures

that are beyond the format

so something like that okay

there is no mathematical way of calculating

how many pixels do you need to have in that operation

so is something to do by I okay

be generous okay

and the best way to search for the information

is at the corners

because in the corners is where you are going to have

more deformation of course

so you go to the corners

and then you have to add enough overscan

just to get the lens distortion to work

without any kind of artifacts

um be careful with this

because if you put a very

very high overscan

that is going to crash the memory of your computer

because of course

you are going to render a huge image

so be careful when you are working with

or scanning okay

just enough

and then when you apply the lens distortion

you will see that there is always a space remaining

of boundary box

that in this case

is going to be useless

so what I recommend is

as I mentioned earlier

is to go to the merch

and then instead of using the default union

you're going to use the B input so in here

everything is crop

outside the area that is not interesting anymore

okay so in here everything is combined together

so working with the boundary box is very important

because it's going to optimise your render time

if you start

losing the track of where your boundary box is

at the very beginning of the script

probably by the end

you are going to have a ridiculous amount of processing

that is useless

so it's going to kill your render times

so pay attention to the boundary box

because it's going to help you um

when things are in a rush

um at the end of the day

they are all in a rush

he's going to help a lot

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 this has been Victor Perez for FX PhD

thanks for watching