All language subtitles for 2月19日

I'm going to jump straight

into a setting you should probably have set up

right now

in your Unreal Engine 5 project settings

search for allow static lighting and uncheck this box

that will now enable Material Ambient Occlusion

which will allow us to go from this result

to this

much cleaner and improved shadowing in indirectly lit

areas you're welcome

if you've been using aluminum in Unreal

Engine 5 for a while

you might have noticed that it is missing the ability

to control ambient occlusion

and while we used to be able to control AO

through the post process volume in Unreal Engine 4

things are different now

now right before we jump into how and

why this all works and a bit of a shameless plug

this video is sponsored by me

in December I released a new tool called evmapper

on the Epic Marketplace

which is now 50 percent off for the next week

etmapper is a master

material setup that supports World Alliance

triplaner texture projection

combined with nanite tessellation and displacement

and advanced vertech blending

all in one elegant package for easy texture blending

on all of your assets

I also just released an update for et mapper

allowing custom grass scale maps

and the ability to paint puddles

so if you've been on the fence

now is the time to get it because it is dirt cheap

you'll find the link down below

okay so let's dive into why Material AO is important

ambient occlusion or AO for short

is a rendering technique used to simulate the soft

shadows that occur in creases

cracks and corners of objects where light is occluded

by nearby geometry or models or whatever

screen space AO was a very popular feature in ub4

and a lot of people are wondering why

it can't be used anymore with Lumen

in Unreal Engine 5

however

Lumen uses a technique called global Illumination

or GI for its lighting

GI is all about direct and indirect lighting in a scene

including effect like

proper color

bleeding and reflected lighting and shadows

from multiple light bounces

unlike ambient occlusion

global illumination

does take into account the interactions of light

with surfaces and materials

AO only take the proximity of Geo into account

not the lighting

so even if a surface is brightly lit

AO still shows up and looks a little fake

in gamey AO and GI

are two totally different rendering approaches

so with lumen a screen space AO isn't

really necessary anymore because GI

take care of the ambient shadows

for us already

having SSAO and GI

would result in shadows that are way too dark

and it just it just doesn't look very good

but Lumen isn't perfect

in order for unreal to run in real time

shortcuts need to be made somewhere

and lumen takes through

shortcut by sacrificing lighting quality

and more specifically lighting accuracy

because while lumen does use ray tracing

it only calculates about half a ray per pixel

while Path Trace renders

need about

200 plus rays per pixel for acceptably noise free GI

so yeah shortcuts need to be made somewhere

there's no free lunch

while Lumen does take care of the general shadowing

between objects

in fact it's really good as of unrealagen 5.3

I've got to give credit where creditors due

but it just isn't accurate enough to get those really

satisfying high frequency detailed shadows

that you get when you compare it with the past tracer

take a look at this render I made in a video last year

the past tracer results are simply better

especially once you know what to look for

fortunately that is where Material AO can come in very

handy which is the feature we just enabled

by disabling

that checkbox at the beginning of the video

don't ask

so here I have this awesome suit of armor model

you'll see that the armor bit

do get a bit of self shadowing

thank to GI and Lumen

you get this for free

but some of those contact shadows still

feel a little bit floaty

like this part here for example

right in between the two metal plates

it should be very dark

not much light should be able to reach in there

if we compare to the path tracer

you'll see that the path trace results

just feel more better

the pieces of armor feel more connected

right here

again if we zoom in to those thinner place metal

the contact shadows here are just

so soft and accurate and crisp

it is all about those contact shadows

but using material AO

we can partly make up for that lack of accuracy

when using lumen

so using an AO map for this model

by plugging the map into the ambient occlusion

slot of the material

we can go from this to this

it is a huge difference

but the really cool thing is that

if I rotate the light around

you'll notice that the AO we added

fades away

it only shows up in indirectly lit areas of your model

it isn't just multiplying the AO

on top of the base color

like that old school thing we used to do back in like

2008 this is great

because you wouldn't want a dark AO shadow to show up

when a big bright light is shining directly on it right

it is another way for us to squeeze out

a bit more detail in those indirectly lit areas

that Lumen really can struggle with a bit

so see what happened if I toggle the AO map on and off

it is a day and night difference

major improvement

now I did add

some additional cavity detail to the AO

map just to accentuate

the example but you get the idea

fortunately every

single mega scan surface you download from the Quickel

bridge comes with an ARD

Ord map meaning the ambient occlusion map is here

in the red channel

but unfortunately the Mega Scan models

do not seem to have AO included

only the roughness and displacement

which kind of sucks

but don't worry

there is a way to bake AO on your models

directly in unreal

so first

you're going to need to enable the modeling tools

plugin by going here to plug in and search for modeling

make sure these are checked

once you restart the engine

you'll find the modeling tool here

or you can use the shortcut

then we can navigate to the bake tab over here

select the model whose AO map you want to bake

and select ambient occlusion from the list

set it so that the AO

map is saved to the correct folder

choose your desired resolution and there you go

you'll have your AO map baked

and ready to plug into its material

easy mapper or otherwise

unrealist seems to use the CPU

to bake the AO maps which makes it a lot slower than

the GPU baking the other apps like Substance

Painter and designer use

but I mean it's amazing to have this baking feature

built directly into the engine

I didn't even know it existed until recently

so I hope you found this tip helpful

thank you so much for watching everyone

and as always folks

happy rendering