All language subtitles for 2月22日 (6)

if you've ever went walking in the morning

you've probably seen something like this before

rays of light passing through mist or atmosphere

in this tutorial

we're going to be talking about the interaction

between the rays of light themselves

and the pools of light that are created

on the surface that it's being projected onto

this is a method that can be used for full CG

environments you can also mix this method with

plates and stuff like that

but it's great for having

a light that's actually cluding shapes that we can see

and the light source is kind of moving

so if we have clouds

or we have some kind of something passing over

that's what this sweeping light

effect is kind of good for

towards the end of the tutorial we'll look at

how to get some of the particles in there

how to make those cut into the God Rey

and how to get multiple layers crossing over each other

and also some problems that we can run into

with screen space God Reys

if we start looking at this and we look at the most

basic God re

this would be one possible approach of making a God re

you kind of create

some kind of alpha

we punch a few holes in it and that's what we want

to create the god right through

so we would kind of put it into position

and put the god right node

and when you have the god right node

you can move the center around

so we could put it here and we could either scale up

you could also scale down from another direction

but essentially the same thing

we get some rays

from that and you can adjust the size with your noise

so you can adjust those ray sizes

by reducing the noise size

or adding contrast

by gamming down

so this pattern is kind of helping it

so the same thing here

it's the same exact idea with the volume raise node

pretty much works the same way just

a little bit different way to control it

but you can put the volume right no behind

and you put the position

kind of behind that light source

and it'll do that effect

now if we want the

god race to actually interact and create

pools of light

this technique is not going to be the way to do it

because we need to have an alpha that represents the

ground so the trick with this is to actually flip it

we want to create the interactive mat first

so we want to start with noise

we actually want the noise to be

kind of on the ground

so I'm gonna show this with a CG environment after

I'm just doing a quick 2d example first

so the noise here we're just doing a corner pin

and kind of getting it on the ground

and rather than God rang down from a light source

we're actually God rang through

these sort of

interactive points so we create the God ray node

and we scale up

so I put the center up where the light source would be

and I scale basically down which creates

this sort of God ray

and what that allows us to do

is to have a mat that represents both the God ray

which is this

but also the interactive point

and so if I gamma down this mat here

to something that looks like this

and we merge these together

you can see that each god ray is getting its own

pool of light at the bottom

and when we animate this noise

it's going to look like the god rays are actually

casting light on those positions

so we have the rays actually matching up

and we could of course

blur this a little bit if you want it

and we can control the mats independently

or we could even you know Gam up

and have a bit more God race or

however you want to do it

but fundamentally this is the idea

but with a CG environment

we can do the same thing with a position pass

so we can create

a 3d noise with

not a 3d noise but a 2.5d noise

that runs across the position pass

and fundamentally do the same exact trick with a

CG environment

so that's what we're gonna do

in just a second here

so if we go here and we take a look at

the position pass

this is what we need to do to create that noise

running across the surface

so to do that it's actually pretty easy

we can do an expression

and what we want to do in the expression node

we have the color channels here

I do have a video on my channel that goes into this

how to like make this a tool if you want

kind of a 2.5 d noise that you can

kind of tool up and use again

but in this case we don't actually need to do that

all we need to do is go to the last

box here which is the alpha

and we want to type noise RGB

and with you know commas in between

like this and if we look at the resulting alpha of that

you notice that we have

a noise pattern all over the surface

so this is great

but it's not moving so we can't do anything with that

so we want to put a grade node

just before

and in the grade node you see it breaks

so first thing we want to do is uncheck

the black clamp because the position pass

has some negative values and stuff like that

to make it work

and that's killing it so we want to turn that off

and what we can do now

is pretty interesting to make this animate

we want to go to the offset

and we can actually just increase this

and you'll notice that the noise will

actually flow across the surface

this is how we can create the base for our

interactive effect here

there will be

one problem with doing this is if you offset it

and you sample

and you look at the alpha

that we're creating the value

if we go kind of like negative with this

you'll notice that we have some negative values

which is not good with alphas

we want to have 0 to 1

so after the expression you'll need to put a clamp

so we have a nice 0 to 1 alpha

and that's what we have now

so what we can also do is replace the red

green and blue channels

so we can get rid of this position pass

and we want to replace all the channels with this

resulting noise pattern that we've created

so we can just put a shuffle node at the end

and say we want to put Alpha

into all the channels like this

so if I hit RGB and a

all the channels look the same which will

work really well for when we put the God Rey

effect on top of this

so we have these nodes that's kind of creating it

and we have this node

that we were doing the offset

so that's where we can go back and animate it

the other thing we can do here

is we can actually go to the

gain or the multiply

and we can actually go

into the colors and we can increase the scale

if you want to make it

bigger in one direction

so we have X y and Z

represented here

so you can basically just

play around with these and see how

how you like it

same with the offset

that's kind of offsetting it in like all

directions sort of

but if you want the god rate to flow in one

direction you can go into the offset and just offset

one of the colors and you see it flows in one

direction now

so if you're creating

a cloud

passing over

this is actually really great way to get those

light effects all over your environment

so this is a pretty cool effect

now all we need to do is create the God Ray so

I'll just go here

we have some kind of gray background first

so I'm gonna fix that by masking

based on the beauty

I'll just mask that so we don't have that kind of gray

because I have the alpha here of the actual scene

which is like this is just like the base base render

and now we can mask that and we're good

now we're ready for the God Rey

so I'll put a God Rey node here

and we will put the center up in the corner

and close these panels

take a look at that

and we'll just decrease the scale a bit

first thing you'll need to

increase the steps here

so we can increase that to a higher number

let's say 10 you can also hit max but

you know that's not going to be what we want

in this case so we can move this up

and scale it down

and we can move it up further

and that's kind of good we can

gain this up a little bit see how it looks

it's a little bit easier to tell

once we start looking at a scene though so

if we take our two mats that we've created this one

and this one

let's apply it to the actual base beauty of the scene

so first I'll take the interactive mat

and I'll just kind of

gain down everything except the light ray

so I'm gonna take the grade

I'm gonna invert that

so there's a little invert button

and gain down

so now we're getting the spots that are only

you know kind of in the alpha here

we can also

do the opposite so we can do the same mat

but not invert it

and we can just kind of gain up a little bit

so we can see what's happening

and so maybe that's too small of lights

but we'll see how it looks

we'll take the god rays and we'll kind of

plus this over

or we could do it over over

it actually be better in this case

we kind of want it to include

and not brighten the highlights necessarily

so over is over is fine

and this is kind of what we have now this is too bright

so we can bring this down a bit

and to make this look better

I think we could just make the noise

much bigger

so now we can start to play with the noise size

and see what that looks like

part of the problem is

yeah we just need to have big

big pools of light being created

to make that a little bit more

convincing here

we can also match the color a bit better

so you know these are white

whereas it feels like we have a bit of a warmer thing

even though the materials warm itself

I think it just looks a bit

more natural if we throw a bit

a tiny bit of color into it

another thing we can do is in the God Ray setting

there's from and to color

so you can basically like

kind of fade off the ends of them a little bit

so it feels like it's not just

like completely sort of a linear effect

but rather it's kind of falling off from a source

and that's gonna help

so let's just see what else can we do here

yeah so I'll make the spots a little bit bigger

so I'll go back to

our little size control that keep going back

and just keep playing with the size

and just see what we can do here

let's just

play around with a scale I think it just needs to be

something

probably like this

sometimes you get a bit of a harsh fall off

because of the noise that we used

so you get these sort of harsh edges

if we look at if we look at the Alpha

we can actually see that

so what we can do is

we can actually blur this alpha a bit as well

so if I go here

blur the alpha

and then I'll just

put this back over itself

so we get this kind of foggy looking effect around it

and we can take a look at what that looks like

and you see how it kind of softens the

edge a little bit

so that we're not getting such harsh edges

and it feels a little bit more natural

so that allows us to kind of control

how broad those those rays go

and starts to look a bit more realistic

now we're going for a pretty

contrasty scene

so we're going like like

dark shadows and stuff like that

if we had a fill light

you know we could play it like that too

or we don't completely

gain to zero here we could have some fill

if we want

so we could just kind of bring it up a tiny bit

but I kind of like the contrasty look it gives it

that really dramatic

sort of spotlight effect

and that's kind of it

that's kind of

how we can get the

effect and you just play

with the noise

and you could do more than one noise pattern

so we have like the big broad one that we've done now

and we can animate that sweeping through

so we can just play with our offset

and that's just gonna feel like

that those rays are going through so

if we were to keyframe that over time

that's what that's going to look like

so you could do like a helicopter or something

you could do some really crazy stuff this way

and even if it was just one singular alpha

with a P mat you could do the same same idea here

so I think that's pretty much it for this effect

I'll go into the comp now to show

how I did just some of the particle effects

be mixed in there but fundamentally it's just this

and then

playing around a lot with like the look and the timing

just have really dialed in

you know maybe you could make your fall off look nicer

you could

once you break up the rays as well

it helps a lot so we're going to talk about that but

fundamentally the main techniques are

not that complicated it's always just about

dialing everything in which means the motion

how much of it

on certain parts of the sequence like if you

start your shot versus your end

what are you trying to tell here

the other thing I guess I could mention

is let's go here to my actual comp

so this is the one that I did

we can just step through

so I created the alpha here

and then I basically just God ray it from that

and then we kind of put it over

but I did also do a negative God ray from

our object it's passing through

and basically just

you're just taking the alpha of this thing and

doing a God ray from that alpha

so if we have

the alpha of the triangle and we're doing a God ray

we can create

something like that and we can also

roto it on certain parts to just make it a little bit

sharper if we need to

and kind of

cut into the God ray to make it look like the

object is passing through

when you're doing that you can

basically the mount that you stencil

it will make it look like it's further inside

or rather the God ray is closer to the camera

and not blocking the object

so if I put it at

0 it looks like this object is sitting

behind the god ray

versus 1 where it feels like it's cutting it out

and you can always

play with it somewhere in the middle too

especially if it's passing through

this is something you probably want to animate

so that's something to keep in mind

so we'll talk about the particles next

so for the dust element

I have a whole bunch of dust elements here

that I kind of

brought in but essentially

without the dust element

we have something that's just like the Godre

and then when you start to bring it in

it just gives a bit texture to that light

which is really

pretty awesome

not always is that the case

because it depends on the particle size in the air

you know if you have a big cloud

or like steam over a lake or something like that

the noise is gonna be bigger

or if you have fine particles of dust in the air

maybe it's a garage

they're gonna be smaller

so it's not always just

you know random

particles in the air

you gotta think about the size of the particles or

the kind of volume you're shining light through

so that's kind of what we have here

we have some finer dust that's blowing around

and basically

yeah it's just a clip of you know some dust here

and the trick here is to

take the

alpha or not the alpha the RGB and alpha if you want

and multiply it against that image so

if I have that disabled

you see I kind of graded it just a bit brown

and then I'm just multiplying

a pre comp of the god rays that I did

up in the top of the composite

so it just kind of helps cut it out

makes it feel like that's hidden

the light is hitting all those particles on that layer

and it starts to become more convincing the more

layers you add so

you know

I added like a whole bunch of different layers here

some at different depths you notice we were

out of focus in the foreground

so I added some particles

just in the foreground that pass over everything

just to give some sense of scale and distance

so those are things you want to think about

and we'll just step down all the way here

and then there's some lens floor

stuff going on that I might do another tutorial

on some of the lens floor stuff but

that's kind of the gist of it

I did do a bit of a sharpening

like crazy on this just

because it's going on YouTube and video

and compression kills really small particles

so it's almost like invisible

so I kind of sharpened it like

almost too much on purpose

but yeah that's that's kind of the effect

and this is the overall look

that you can get

again you can go further with this

if this was like feature film

and you needed some God rays

you know for example

like something you could do even more

you have like the

shadow cutting out you could put

another God ray behind

and just so you see some shapes in that cut out

or just some stuff going on in the background subtly

or even some very foreground

subtle god rays coming over the camera

you could flare up this corner and have

have some subtle

hazing coming from off screen

so there's all kinds of more

things you can do

depending on the amount of time you want to spend

on things so

you know I'm not gonna spend infinite time on this but

I think this is a pretty cool result and hopefully

that was useful for somebody so if you guys liked it

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