MAKE YOUR GAME RUN SMOOTH - Unity LOD Tutorial Video Lecture | Build a Game: Unity Tutorial (English) - Game Development

when making levels you of course want
them to be as detailed as possible but
just throwing a bunch of high quality
models into a scene is not very
performant especially if your scene is
fairly large of course it makes sense
for the models to be detailed when
viewed up close but for objects far away
this detail isn't very important this is
where level of detail or LOD comes in
here we basically create multiple
versions of each model at varying
quality and then swapping the right
version depending on the view distance
if done correctly this can be pretty
much unnoticeable and make this scene a
lot easier to render the cool thing
about setting up lots in unity is that
if you organize your assets in a certain
way unity will pretty much do everything
for you so first we'll go over how to
create multiple levels of details for
your assets in blender and that will
bring everything into unity we go so as
you can see I'm here in blender 2.78 and
what we're going to be doing today is
not particularly advanced but if this is
the first time you're opening up blender
I suggest you at least check out the
first video in our blender basics course
all right so first I want to select the
camera then hold down shift and like the
Sun and cube as well and hit X and press
delete so now we have an empty scene of
course you can go ahead and create
whatever asset you want here but I'm
just gonna go and create a monkey so
let's say this is the game asset that we
want to create multiple versions of well
I think first of all we could create a
level of detail that is even higher than
this one so I'm gonna go to the
modifiers and I'm gonna add a new
modifier and I'm gonna choose
subdivision surface so this adds a lot
of subdivisions to our model I'm gonna
go ahead and apply these and if we
switch into edit mode by hitting tab we
can see that there's quite a bit of
detail on this model so this represents
our base model our model in its highest
quality we refer to this as lawd
zero so I'm gonna go to the top here and
find our model our monkey's name is
Susanne that's right it's a girl so we
can right-click on Susanne and go rename
and we'll right underscore LOD for level
of detail and then I'm gonna put a zero
here
and this is one of those unity specific
things that we have to do this exact way
judy is going to look for this
underscore LOD and then an index and
then recognize what it means so we can
then go ahead and create alternate
version
offices and so I'm gonna duplicate her
by hitting shift D and I don't want to
move her around so I'm just gonna right
click to snap her back to original
position now this one I'm going to
rename to LOD underscore one and I want
to go and move this a SAN on to another
layer to do that I'm gonna press M and
I'm gonna select the second layer here
and as you can see down here there are
now two different dots on these two
layers because there's an object on each
one and we can switch between them of
course we have the same model on each
layer but we are now only viewing one of
them at a time and we can always quick
switch between layers by using the
number keys so now we want to reduce the
quality of this model of course the best
way to do this is go in by hand and
simply remove polygons but this is also
very time-consuming often you can get
away by simply adding a modifier so
we're gonna go add modifier and we're
gonna select decimate here we can adjust
the ratio and right away you can see
that we are slowly compressing our model
I'm gonna set this to a value of 0.5 I
think that's a fairly decent starting
point and then I'm gonna hit shift key
once more go to the top and renamed to
LOD 2 and again I'm gonna hit em to move
it on to another layer and I'm gonna
select the third one then I'm gonna
press 3 to move to that layer and I'm
gonna reduce the ratio even more I think
I'm gonna try a value of 0.2 again shift
D to duplicate right-click go to the top
and rename finally we'll call it LOD 3
again move it to the fourth layer hit
forward to focus on that layer and this
time I'll bump the ratio down to say
point 1 so now we should be able to use
our number keys in order to see the
transition between our different levels
of detail of course this level of detail
doesn't look too good but remember we'll
be viewing it from very very far away
and on top of that our model currently
uses flat shading if we selected and go
to the left here we can hit smooth and
that definitely helps hide the
subdivisions so I'm gonna do that for
each one of our models and I'm also
going to go through and apply each one
of the modifiers so hit apply on the
modifier go to the 3rd layer apply 2nd
layer apply and of course our first
layer does not have a modifier and that
is actually all of this set up
that we need to do if you want to
preview how many triangle makes up each
level of detail step you can see that at
the top here so the first one is about
4k the second one is about half of that
the third one is under a thousand and
the fourth one is just under 400 so now
we're ready to export this into unity to
do that we'll go file export and we'll
select FBX here we can browse to our
project folder go under assets and I'm
gonna save mine as monkey and let's hit
export FBX now when we open up our unity
project we can see right away that we
have an FBX in here and under it we have
the four different levels of detail and
this is where unity is just so awesome
because if we simply take the parent
object here and drag it into the
hierarchy right away it sets up
everything for us because unity
recognizes that this object has multiple
sub objects that are all marked with a
certain level of detail and so it goes
ahead and creates this LOD group now
before I show you how cool this is let's
go ahead and drag our object up here so
we can actually see it let's also look
under the object here we can see all of
our different levels of detail if we
select all of them we can create a
material for them so we'll go
right-click create material we'll call
this material red will set the
smoothness to zero I'm gonna set the
color here to a nice red and once again
I'm gonna select all the objects and
drag in the red material and if we then
select the parent object it will clearly
indicate in the scene view what level of
detail we're currently looking at and as
I start zooming out you can see this
camera here is moving towards the right
that's because it's showing us how much
space our object is taking up on the
screen and as we zoom out it takes up
less in there space and in fact if we
zoom out just a tiny bit more it's going
to switch to LOD one if we zoom out even
further LOD two and even further LOD
three now we can't actually see this
happening and that's of course a good
thing if you want to see this happening
more clearly we can go and switch to
wireframe and here we might be able to
see the amount of wires change as the
level of detail changes but still that
might not be completely clear so just to
demonstrate we can go and select each
one of our level of details and we can
add a separate material to each one so
the first
here's gonna be red I've gone ahead and
prepared a yellow material as well
a green material as well as a blue
material and now as we zoom out you can
see that our object changes color super
super cool we can also go ahead and
select any one of these Elodie's and the
LOD is going to show up down here it's
gonna display the amount of renderers
and materials as well as the number of
triangles so we can go through and see
the number of triangles here as well and
this is also where you can set up your
own renderer so in case we didn't have
the right renderer we would go in and
remove the one that we have instead he'd
add and now we can go ahead and select
any object here but of course we want
the first one so how does this look
within the game view well it looks
pretty much the same if I go ahead and
take my scene view here and target on my
secondary monitor I can try zooming out
with the camera and you should be able
to see the exact same thing happening
awesome that's pretty much it for this
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