Complete UE4 Lighting Workflow for Arch Viz Artists | Light Types / Light Bake / Lightmass Settings

Complete UE4 Lighting Workflow for Arch Viz Artists | Light Types / Light Bake / Lightmass Settings


Okay, VR peoples, we’re gonna do a video
now that is all about lighting and I think it’s long overdue because I know
that when you’re coming from mark vis understanding Unreal Engine can be
difficult especially if you’re just used to 3ds Max and an offline renderer like
v-ray and one of the biggest things that you have to overcome is completely
revamping your mindset when it comes to lighting because the lighting works
totally different in real-time than it does in offline renders so I want to go
over some of the theory of lighting in Unreal Engine I want to go through some
of the techniques the different kinds of lights and how to wrap your head around
light baking and understand what exactly is going on and how to make it look good
okay so stay tuned for all of that what I’ve
done so far is just make a basic scene it’s just a box I’m in the first person
shooter template it’s got a sphere inside of it I use some of the new
substance materials and applied it there’s a basic direct light out here in
a skylight okay fantastic everything is pretty straightforward so far we do have
a light mass importance volume encompassing this scene as well you may
know that the direct light that comes standard in the template is set to
stationary so let’s first talk about the differences between stationary static
and moveable lights if you hover over them they’ll tell you what they are
static is fully baked lighting fastest rendering obviously it’s baked into the
scene so when you do your build and you build your lighting it is actually
baking it on to this and none of it is being computed in real time stationary
is a hybrid it can’t move but it allows partially baked lighting and dynamic
shadows follow or dynamic shadows from movable objects okay so keep that in
mind it’s a bit of a hybrid and then there’s the movable light which can
actually be totally dynamic and move throughout your scene in real time whole
scene dynamic shadows slowest rendering obviously and it does not contribute to
the light baked okay so what is the light baked the light baked is where we
you can think of it as your global illumination if I put a light out here
that is say this was static it would calculate
all the highlights it would even bounce lighting calculate where the shadows
will be where the highlights will be and then it will map it on to these objects
that is what light baking does so there is global illumination going on but it’s
not happening in real time or baking it in so when would you use these different
kinds of lights well let’s test them all out first I’m gonna set the Sun to be
static okay and then we’re just gonna do a basic light build will go to lighting
quality preview and just build the lighting what this is going to do is
bake in all the global illumination and the direct lighting from that static Sun
coming through my little silent skylight up here and lighting my scene
so we’ll see what kind of results we get all right there we go so you can see the
direct light coming in and you can see that global illumination is happening
because the rest of my scene is also lit up I’ve got a cool reflection on this
tile right here that’s awesome you can also see some shadowing going on
underneath of the ball it’s not very high quality but that’s because of
settings it’s also because my build lighting quality was on preview so
there’s lots of different things that go into that
that is for another time right now but there you go there’s the baked lighting
you can also see that in the corners there’s some ambient occlusion going off
and that’s kind of tricking our eyes a little bit showing lighting that isn’t
actually there isn’t being calculated by the light baked so let’s just turn that
off for now go into project settings ambient occlusion let’s just turn it off
entirely okay there you go so there’s our light baked without any
ambient occlusion and you can see that works pretty well actually I’m gonna
turn off one other thing to the auto exposure and what this does I mean we
can obviously turn these back on later we can also do them through our
post-processing volume but right now I’m turning them off so that we are getting
rid of all the different variables that can be going on here okay so you can see
it’s considerably darker here there is a little bit of light in here
but it’s not very bright let’s actually turn up the Sun 15 one thing to keep in
mind is this skylight up here you can actually apply nhgri map to it right
here and light your scene with an hgri so that’s cool of course that’s probably
something you’re used to right let’s turn up the intensity of that – let’s
bake it again get some more light in here okay now it’s brighter boom we got
the scene lit up a little bit in here so without the exposure settings it’s
still working you can see there’s a little bit of shadow coming off this way
that’s because there’s a bright highlight right there casting a shadow
so you can see there’s global illumination going on now the global
illumination is not very high quality that would be adjusted in your world
settings here under light mass and it’s basically these five settings right here
okay the most basic way to adjust this would be to up the number of indirect
lighting bounces okay that will make it higher quality you can put it at ten you
can put the skylight bounces do something higher as well perhaps even
ten and then the indirect lighting quality you could put up to six this is
very high settings and you can even adjust these downward below one this one
and this one to make even higher settings but that will up your build
times dramatically so this could be considered sort of like your secondary
bounce render settings your GI render settings like if you were using v-ray
okay they don’t translate directly but that’s kind of the kind of quality that
they’re controlling okay so look up the documentation on this and you’ll see
that going like a hundred bounces gives you a very little difference from ten
bounces but the difference between ten bounces and one bounce is is very
dramatic okay so you don’t necessarily want to just crank this and crank this
higher and higher but this number the indirect lighting quality will actually
give you considerable about more quality it also makes your build times go nuts
so let’s do this this well actually for now let’s just put this down pretty low
okay and we’ll leave this at 1.5 because I’m
just demonstrating here but the numbers I had before could be used to get much
higher quality stuff but I don’t want to wait for all these billed times well I’m
just trying to demonstrate okay so that’s that let’s build that one more
time to look and see what it looks like and here preview medium high production
this is going to be also contribute to how accurately it’s calculating
everything so you can see a choppy edge on this shadow up here if you put this
lighting quality too high or medium then you might start seeing that go away I’ll
put it on medium and build okay that didn’t take too long at all
you can see the shadows looking nicer now obviously the corners are getting a
little bit darker because the GI knows that not as much light is getting into
those corners anyway overall our calculation is getting better you can
see that this is a nice soft shadow being cast here under that wall little
sharper up on the top so that’s all in our quality settings okay so that’s that
I talked about that elsewhere in other videos okay but I want to talk more
about this stationary light we’ve got up here or they sorry the static light okay
that is static so everything’s being baked in what if this was an object that
we were going to pick up in VR and move around what would we do then
well we change it to a movable object and then we go down and say in the
lighting okay if this is a movable object then we don’t want it being
baking shadows onto the ground because then when we pick it up there’ll be a
big black spot there that we don’t want let’s just do that as an example
actually it’s already done it’s baked in if we moved it then that shadow would
just remain there okay we don’t actually want that so what we do if that’s gonna
be a movable object we would make sure that in the cast shadow settings it
doesn’t cast the static shadow but it does cast a dynamic shadow okay now we
could change this to a stationary light which of course will bake some of the
lighting but it will also cast dynamic shadows
okay so let’s build that and see what it looks like okay you can see that the
star lighting is not working on this anymore
it’s no longer casting any shadow down here and it’s not getting darker as it
goes around this curve or anything like that it looks kind of dramatically
different but it is something that you can pick up and notice what happens when
you move the ball around and especially if you moved it over to here into the
shadow voila look at that
so that looks realistic when you pick it up and move it around that’s actually
really cool so the stationary light would be awesome in your scene
if this is the kind of thing you want to do if there’s gonna be a movable object
moving through that direct light that’s why the Sun by default is set to a
stationary light so that it can do these kind of things
so if you have movable objects the lighting still works ok so that’s pretty
cool actually that looks really good however if you’re in your scene and you
want the Sun to move it would not work that is not a movable light is only
stationary and the other thing to remember about stationary lights is you
can only have so many of them what’s the number 6 where is it for I don’t
remember but you can only have so many of them overlapping with each other if I
took now a spotlight and put it into the scene here made it stationary right and
then I made some more stationary lights now we’re at 1 2 3 plus the Sun 4
overlapping v 1 gives me a red X ok so that’s because these these cone shapes
are overlapping with each other you can’t have more than 4 of those cones on
stationary lights overlapping with each other okay so you have to keep that in
mind you can address that by making the cone smaller and then making the lights
further apart or you can also change the attenuation radius so that it doesn’t go
it doesn’t influence as far away but as long as these cones are intersecting
with each other that counts as one light and you can only have four of them that
are stationary and overlapping like that okay so that’s another thing to keep in
mind with moveable you’ll have similar problems and this will also slow down
your potentially slow down your real-time rendering dramatically if you
have a bunch of fully dynamic lights but if you wanted to animate the Sun then
that’s what you would need you knew you need a movable light or if you want a
light that turns on and off and those kind of things completely dynamic right
and it creates dynamic shadows it does not figure into the bait lighting at all
so that is the difference with that so for arc vis I think we’re probably using
most of the time static or stationary lights but we want might also want to
use moveable especially if you have interaction going on with those lights
okay so this one will probably leave a stationary as well we’ll bake it one
more time okay there you go all baked this thing doesn’t leave a big dark
shadow there because that light is stationary and the shadow remains
dynamic and then when we come over here you’ve got a dynamic shadow as well
which is pretty cool looking actually okay so that is the difference between a
static fully baked light and stationary lights / movable lights with dynamic
shadows okay let’s change this all back to static for one last test that one’s
static and that guy static and this guy light aesthetic we’ll do one last test
here we’ll build it one more time see what we get oh we forgot to do one thing
so everything’s baked but this thing is not casting a static shadow so really it
doesn’t look right at all make sure to turn that static shadow back on right
there let’s try that one more time then you got to also make it static object
try one more time okay so here you go this is all baked lighting right so if I
move this it’s gonna look wrong right away totally wrong and immediately it
says lighting needs to be rebuilt you can’t move static objects okay that
shadow will remain there everything will look incorrect okay so
when we’re doing our quiz this might actually be the way that we want to use
it most of time if it’s just a scene that we’re gonna walk through and
nothing’s gonna be moving around and we’re not gonna be interacting with
things everything can be static including the
lights but if we’re getting into VR and we’re gonna walk over here and pick this
thing up or if there’s anything dynamic going on like okay I want to switch this
ball out for a different ball or for a different material or I want to move
this ball over here then you have to start thinking about what kind of lights
you’re gonna want to use what kind of shadows you’re gonna be one of using
won’t need to use okay so like I said if you’re seeing static you can do
everything static you can bake crazy complicated lighting schemes just bake
it in and then nothing’s calculated in real time and everything will run
smoothly okay so hopefully that helps demystify some of the lighting
techniques going on here helping you understand the difference between baked
vers dynamic lighting and how to get the effects that we want now the only other
thing I want to look at is some of these optic optimization view modes right now
we’re in lit if we go to detail lighting it’ll show us just the lighting and you
can see this here see this shadow here how choppy it is and how choppy this
shadow is some of that can be addressed by doing a higher quality light build
but really a lot of that is dependent on another view mode here which is the
light map density optimization View mode light map density you can see that this
is how dense our light maps are and of course the light map is like like a
shadow map and in 3ds max maybe but it’s basically a map that tells where the
highlights and shadows are on each face of each object individually that’s why
we do the UVW unwrapping so let’s look at this static mesh by double-clicking
on it let’s look at the UVs okay that’s not the right channel this is going to
be our Channel it was automatically created on import when I used data Smith
to import you can also automatically create that when
the FBX import but you notice each face needs its own unique space to have that
light map applied to and then you have to make sure that this UV channel is the
one that’s accepting the light map and then you make sure that lighting
resolution that light map resolution is high enough so light map coordinate
index is set to two which is the right one it looks great everything’s
separated we could up this to 1024 and save it and then when we’re back in our
mode now we’re getting a really high resolution on that thing red means high
resolution and you can look and see how big these squares are to know how much
resolution there is and that should be sufficient okay so that’s a big way
let’s look back at our lighting okay everything’s gonna have to be rebuilt
now because we’ve changed the light mask
settings the light map settings and they should be higher quality now and let’s
go with a high quality build build the lighting again we’ve got our light maps
at the right resolution and let’s see what we get here it should be a pretty
good result the only other thing we would do after this is go back to those
world settings I will show you and up those settings really high which that
will be our last final test I promise ok so this looks pretty awesome getting
some clean results down here we could probably go even higher with the
settings for this particular shadow here higher light now setting or higher light
map settings and then a higher quality build we are getting some nice sharpness
up here in this shadow and then softness as it comes down
overall this Lighting’s looking pretty great you can see that without ambient
occlusion turned on at all you’re still getting dark corners and things like
that so the global illumination is working quite well so the last test
we’ll do the last and final test in this video is just to up our settings so I’ll
just go with something that I’ve found to work basically well and I’m not gonna
claim that this is the best settings for this all around but these have worked
pretty well for me now the time in the build is gonna go
way up so I’ll pause it and I’ll build it I’ll show you the results okay here
we go I cranked the settings up I even went to lighting quality production
level okay I exaggerated a little bit on how long it was gonna make my render
times because this is a simple scene so it it’s still built the light really
quick but on a big scene with a ton of lights and lots of light map resolution
going on it can take a really long time so keep that in mind but this is the
kind of quality of lighting we can get and this is still a little choppy down
here the best way to address that would be to turn off the light rat map
resolution do something ridiculously high on this object here and that would
eventually take care of that okay so you can see that the global illumination is
actually pretty high quality right now look at this corner up here you can see
that the the bouncing of the light is going quite well there’s a nice crisp
shadow right there that gets softer and softer as it comes down the wall
everything is quite realistic actually okay as you can see the lighting looks
pretty dang good here everything is nice everything the light bounce is going
very well so that’s the kind of results you can get if you can get away with
making everything static you can get actually get very photorealistic
lighting going on inside Unreal Engine 4 and if you need things to be movable
then you isolate those objects with the proper lights that they need and the
proper type of shadows they will not look as realistic if they are
interactive and they cannot do these nice static shadows but they will remain
fairly accurate and at least represent shadows properly on your scene
so hopefully that helps you guys out transitioning from v-ray or Corona or
some other offline rendering program into real time rendering with Unreal
Engine 4

22 thoughts on “Complete UE4 Lighting Workflow for Arch Viz Artists | Light Types / Light Bake / Lightmass Settings”

  1. Great tutorial, but how do you get around the problem of moveable meshes displaying a lot lighter when turned to a moveable?

  2. Good explanation, thank you! Can you later on address the new measuring light units in UE4, lumens and candela? They don't seem to work as in real life and this is bugging me so much. Especially if you adopt the new exposure method, set the exposure to MANUAL and start using the camera values as in real life.

  3. I dont think the prouction quality looks THAT good. I wonder how do people actually achieve photorealism in Unreal? It must be in Unreal most of the settings right?

  4. hi I have a problem that I can not solve. I can not completely darken a tunnel in a level where there is a stationary skylight or if I set the skylight on static the tunnel becomes dark but all the other shadows like those of the trees are dark.how can I make the tunnel completely dark without having to set the skylight on static?

  5. nice gathered light tips. finer original mesh helps with shadow mapping as well, if i am not mistaken.

  6. I have imported this Datasmith object (mesh) but its seems to knock it off from my folders as soon as I build my geometry.

    its gives me this message.

    " Static Mesh actor has NULL StaticMesh property" then my mesh disappears from my scene and folders… do I need to turn it into a static mesh.. how you do it?//

    SOS.. Thank you in Advanced!

  7. this raises more questions tha it solves. what if i set the skylight to stationary? why would I set my sunlight to static if stationary does the same PLUS dynamic shadows? what about the objects, whats the difference between static and stationary objects? also why did hou set it not to cast static shacows? shouldnt movable objects not caat shadows anyway?

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