All language subtitles for 2月29日 (7)

guys welcome to this beginner video

intended for people to learn how to use Uvs

a nuke and just kind of what a UV passes

a little bit about UVs in general and then

you know some of the

practical ways that we can actually use them

so this is again this is a beginner video

I'm intending to make an intermediate video

and then an advanced video

about UVs because it's a pretty in depth topic

and there's all kinds of stuff you can do

with ST map and

UVs in general on 3d objects and as a compositor

so there's some creative ways we can use those

in the future

but this is more of a beginner video

I split it into basically

two parts one goes in the Maya

explaining UVs and then the second part

will go into a nuke and check out some of this stuff

so if you guys want the project file

it's in the description below for free

and you can download

there's a couple assets that come with it

so you can actually play around

and follow along if you want

in terms of using some of these images here

and I've also provided one of the

I've provided this car render for free

just one frame of it from my full nuke303 class

it comes with the UV pass as well so you can actually

use this and learn the technique

so without further ado

we'll get into the tutorial

so for the first portion that we're looking at here

it's really just

the fundamentals of CG

very much so the basics

but I just want to cover this part in case some people

don't have a 3D background

some composers actually have no 3D background

but I really highly recommend that you

know some 3D as a compositor

as it's gonna give you a really big advantage

and you're gonna

understand where things are coming from

when you're working in nuke

so I really recommend you get into Maya or blender or

one of the other 3D softwares they're widely used

and understand these concepts

so we're just going to briefly cover this in Maya

as this is an easy way to explain what UVs are

and then we're going to go into more

about what we can do with them in nuke

and why they're relevant to us as compositors

so

the basics of Uvs is very simple

so you have this texture that's

wrapped onto this cube here

and essentially what you're doing is you're wrapping

a 2d image onto a 3d model

so essentially what you have to do

is take a 3d model and you need to unwrap it

so this is the unwrapped model

so you can see if you imagine like a piece of paper

you know if you were to cut this cue up

and flatten it

this over here on the right is essentially what that is

it's just a flat version of the model

and if I turn on the texture view

we can see that we're mapping

this kind of colorful checkerboard texture

onto this model

and we

hit this button here and I select one of the faces

you'll see that

this face here

when I'm selecting the top of the

cube is actually highlighting this specific square

so we know that that

texture here so you can see the numbers 8112

are being mapped onto the top of that cube

so essentially just taking 2d picture putting on there

of course

you can manipulate UVs if you're in a 3d software

so you can grab this UV

and I can move it around

and it's not going to change the geometry

it's only mapping

it's only changing the way this

2d texture is being mapped onto them

geometry so we can slide that around

and now you see that the top here is 2334

and also

what you notice is that the side here is a bit

stretched and diagonal

and that's because you can see if we

turn off the view

you can see that these lines are diagonal

so we're trying to map

a straight image onto a warped UV

so that's kind of a problematic

area so that's not how you want to map your UVs

you want to make it so

the lines flow the correct direction

so that's essentially what UVs are

and so when you're getting a UV pass in nuke

you're essentially getting

this

layout

this kind of layout and you can remap a new texture

in nuke onto this layout

so if I have these cubes like this I can you know

put a different texture

and it's going to wrap onto different sides of the cube

without going back into 3D

and so

the reason for this is because you can save time in

production

and if you want to change or add some texture to CG

that has already been rendered

you can just do it quickly in post production

and you don't need to rerender or go relight anything

you can actually just

do it in nuke

so that's the reason we want to talk about Uvs

and now we'll start to get into you know

other things we can do with UVs

and just a couple examples and going over it

so as we covered in the previous section

this is kind of the same concept

and we're just looking at this inside of nuke now

so I've kind of just laid it out

on top here as the 2d view

and then we have the 3d object underneath

so on the left side here we have the unwrapped cube

so this is brought in from Maya

this cube and the cube is unwrapped like so

so we can see the 2d

layout and we can see the numbers on here

so for example that us again that top face

we have the numbers 8112

and we can see those on the top here

and just remind you guys

this picture of all the numbers

that's just for referencing

where things are on the cube

it doesn't mean all these numbers

they don't mean something special

it's just a reference texture

so we can see that's wrapped around the object here

and on the right here we have one

that's called a normalized UV

layout which means every single face is mapped

basically over the same image

so all of them are mapped exactly the same way

so if we change

the image here it's going to change all the sides

exactly the same

so it's not wrapping around really there

all of the faces are exactly the same

so that's a little bit less useful but this is actually

important to know because by default

nuke is actually doing this

with a default cube

it's creating this

it's called a normalized

UV layout

so

again so this is kind of when I keep saying u and v

this is what this is referring to

it's just an x and y

representation

so x and y coordinates

of a 2d image

the reason we don't use X and y

we use the letters U and V

is just because in 3D we're already using the term X

y and Z pretty frequently

so it's just confusing to have the same letters

so use horizontal and VS that vertical

line here so

that's UVs but now we only want to talk about UV

renders so we can actually render out a special image

so if we go down here

this is a cube that's been rendered

so we have a cube with a basic texture

on it and we also have a cube the same cube

with this special image and these images are

I'm gonna get into it

more in an intermediate video

on how we can actually create these special ramps

so these gradient ramps are basically telling nuke

the 3d coordinate system

even though you don't have a 3d model anymore

so this is a 2d image rendered from a 3d object

so we only have 2d images

but this one is special so we can basically use this to

wrap textures around the 3d model

without having to actually load the 3d model into nuke

so I don't need to actually go and load

and bring the entire model in from Maya

so if this was a character something more complicated

we don't need to bring in the character

model we just need to have a 2d render of the UV

pass here

and so with this UV pass

if we plug it into an ST map node

we can switch the ST map to switch it to RGB

and essentially what that does

and the reason we switch it to RGB

is because this is saved in the red

green and blue channel

so we can see we're in the normal

layer here which is the red green and blue

and if we switch from red and green

we can see there's some

information in these gradients

and so by setting that to RGB

and plugging a source which is another picture

it will wrap around that object so you see

we have a picture a 2d picture of some vines here

and when I plug it through the ST map

it's wrapping

around that 3D cube

without having a 3d model involved it's just using 2d

so this is basically just a 2d trick

and we can retexture 3d objects

very quickly without having to render them

so I can move this texture around

if I go to here

I switch the

transform you see I can move these vines instantly

and I'm not doing any kind of

rerendering or anything like that

it's just a cheat basically

then we have down here just some lighting

so we can multiply some lighting on there

and that's just a simple example of UVs

so you're like well why wouldn't we just you know

take the vines and render these in CG

and probably would with vines

because you're gonna get better

looking vines than maybe a

2d image but there are certain

aspects that you might want to do it in compositing

such as

if you're gonna simulate water running down this cube

that's gonna be an expensive thing to do

and it's gonna take you a lot of time

whereas if this is far enough away from the camera

we can take a video of raindrops on

glass and then we could just

put that on the cube

and now it's gonna look like the raindrops are

running down the cube

and we didn't have to go into Houdini

or do any kind of advanced simulation

we're basically just saving time and saving money

so again that depends on your

shot it depends on

how far away this thing is from the camera

so if it's a hero shot and you're looking

up close you're probably gonna need some 3D drips

but if it's something that's a little bit further away

we can use 2D tricks like this

and save production time and essentially

uh that's how you have to always think of things with

CG's if you can save time

save money uh

you know and

uh is pretty important to think that way so

this is another example

I've given you guys a free

basically frame from my full class which is the

CG composing class

some of you guys have probably already taken this class

so this video is a little bit more in depth on the UVs

but you know we have

this is almost a 8 hour class

on CG composing specifically

so yeah so this is kind of

just more on this so we have a car render so beauty

and this doesn't have any layers it's just a JPEG

and we have a UV

render of this car as well

so we also have something called the UV layout

which again I told you guys about

with the cube

but instead of it being a cube

we can see is just this car

cut up into

pieces and put flat so we can see all the pieces here

and if we

want to put for example let's say we want to put

a color wheel on the back of this car here

so if you look at the car let's say I want to put

this picture

onto the back of this car

well I'm gonna go here to the UV

layout to figure out where to place it

so I go to the UV layout I looked for the piece

and I actually unwrapped this car because I modeled it

so this is actually the piece

so I can place that cube

so what I've done is I've taken the cube

I've reformatted it into a square

it's just a bit easier because

these UV layouts are usually square

so I've reformatted to being a square as well

and then I've just

transformed it and we can basically just move it around

and I'll grab it here put it on the back of the bumper

and now if I run it to the ST map so I plug in the UV

render and plug in the picture that we've just placed

and I've used this

you see I'm doing two different things

here I'm using this as reference

this kind of merge over here

and on the left here I'm actually doing the the

ST map

so this is just for reference that's all this is for

so we transform that and we can ST map it

and you'll see

we get this result where it's folding on the back here

and if I merge that picture

this result from the SD map over the top of our

render we can see

that's been placed on the car

and we can of course move this around

so I can take the transform

use up and down arrow keys and slide this around

and it's going to wrap around the CG model

and again we're just dealing with two 2d images

we have the the

the beauty render of the car and we have the UV render

so that's pretty cool

so one thing you might be confused about

is you look at this thing and you're like

well I didn't unwrap this model

and if you have a really complex model

you might have a lot more pieces than this

you're like well where do I

you know how do I you know if I want to put

a color wheel on top of this

this tire here

you might be confused when you look at this picture

and then you're going to be moving this

color wheel everywhere

like well I don't know which piece is

the right spot to put it

and that's where this tester material comes in

so that's where

that material we've been using

if we plug that into the ST map

and we just let that go around the car

that's why this material is useful is because

we can see all these colors

and they correspond to this picture

in this square image so for example we see this

3 here and a 4

3 and 4 next to each other

the 3 is white and the 4 is pink

so if we look at this thing

where is a 3 white and a 4 pink

what's right here

so 3 and 4 right here

and if we go to the corresponding place on our

template we see that that area is right here

so that's what that's just telling us

it's just telling us where

on this thing

it's going to land so 3 and 4

so if I put my color wheel

over in that spot

the 3 and 4 and then I plug that into the ST map

you can see that is being wrapped onto the right place

so that's that's what the tester materials for

it just helps

if you don't know where to place things and

that's one way to do it there's many ways

but yeah so hopefully that helps out

some people

and we can slide it around here and that's how it works

so this is again 15 bucks if you guys want a full

CG composing class

which has a lot more detail than this

about different things

this is one aspect of CG compositing

I'm gonna make another video

more intermediate

UV uses so we're gonna get into more advanced stuff

how we can actually generate these

use expressions to generate these patterns

and eventually

after that I have some plans to do an advanced UV

video on YouTube which is gonna be

things that even senior composers

will probably benefit from

if you're a senior composer following this channel

so I kind of have a range of people here

so I'm gonna try to

post beginner and

intermediate content most of the time

and occasionally post you know

senior level

tutorials out here so that people can get use out of it

so if you guys liked the video

hit the like button

and it helps out a lot and thanks for checking it out