Unreal Engine / UE4 Basic Blueprints Tutorial: Common Terms and Concepts

Unreal Engine / UE4 Basic Blueprints Tutorial: Common Terms and Concepts

Okay, as you know we’re gonna dive into
making some interactions with our scene, but before we do that I know we’ve gone
over blueprints a little bit in previous sections I’ve demonstrated how to do
some things but I want to talk more about the basic building blocks of
blueprints so that it is not so intimidating as we move forward so in
this section we’re gonna talk a little bit about the blueprint basics here and
then we’re gonna go on and do some more demonstrations about how to make things
work if you don’t have any knowledge of computer programming blueprints can seem
daunting but have no fear here are some of the basics we will discuss in this
lecture blueprint classes variables arrays how to control an object from the
blueprint of another object first blueprint classes any object in ue4 that
you attach a blueprint or script to creates a blueprint class in the ue4
documentation the definition is this a blueprint class often shortened as
blueprint is an asset that allows content creators to easily add
functionality on top of existing gameplay classes so we’ve seen that
we’ve taken a basic actor in our scene a static mesh a light whatever it is and
we’ve hit the add blue print button and added functionality to it that is
actually creating a blueprint class when we do that and it’s named whatever we
name the blueprint when we created now each blueprint has a parent class
all blueprints fit into a parent class which determines what kind of behaviors
that blueprint has what we are mostly concerned about in this course is the
actor parent class because most blueprints we’re using our attach to in
actor in our scene this is the parent class we will be mostly concerned with
when we take an actor in our scene a static mesh to light etc and click
blueprint slash add script button this is creating a new actor blueprint class
and you can see in this image that’s attached here from the documentation
that there are other types actor is the top one there’s also a pond a character
a player controller and game mode and you can read their what those different
ones do and you’ll see that those are in our scene already
based on our template and we don’t really need to adjust them
so when we’re creating new blueprints it’s going to be with the actor parent
class variables if you’re not familiar with programming you might not know what
variables are but we’re going to use them quite a bit in our scripting
variables are containers that hold information they are used to label and
store data in memory so they can be used throughout your blueprints from the
documentation again variable types variables can be created in a variety of
different types including data types such as baleen integer and float as well
as reference types for holding things like objects actors and particular
classes arrays of each of each variable type can also be created each type is
color-coded for easy identification so the thing I want to make you aware of is
that it says that reference types for holding things like objects actors and
particular classes can be variables so if you’re familiar with programming you
know there’s various different kinds of variables but in ue4 the unique thing is
that you can turn objects or any kind of actor or any of those blueprint classes
that we’ve created into variable types so what really does that mean here’s
some of the variable types okay we’ll go over them there’s abilene which is
basically just a true or false piece of data that boolean that variable equals
either true or false there’s an integer which is whole numbers without decimals
and you can see examples there on the right there’s float which is numbers
that need decimals after it such as 0.05 5 3 ok there’s a string which is just a
group of alphanumeric characters such as hello world that will be magenta there
is text vector okay a vector is basically a collection of three
different numbers okay like it says their numbers consisting of float
numbers or three elements or axes such as XYZ or RGB information so you notice
when we use materials we create a constant three vector that’s basically
just three numbers and they are controlling the are G and B channels of
that to give us a color the red and blue channels of something to give
us a color also like the location of an object in the 3d scene is three axes
right XY and z axis that’s also a vector three different numbers that represent
where an object is placed in the scene there’s also rotater variables which is
a group of numbers that define rotation in 3d space
there’s the transform variable which combines translation the 3d position and
also rotation and scale so that is basically a group of three different
three vectors right because the position is a vector is three vectors well is a
vector of three numbers the rotation is a vector of three numbers and the scale
is a vector of three numbers all three of those combined together gives us the
transform variables and then there’s the object variable which is basically like
it says here represent objects including lights actors static meshes cameras and
sound cues so basically all the stuff in our scene that we’re one and two
adjust can be a variable type and that’s the blue ones and they’re object
variables okay that might not make a lot of sense now but when we get into our
blueprints and start creating things you’ll see how this all comes together
so keep these terms in mind and these different variable types an array is
just a collection of variables all put together into one group and they’re of
the same type so all the variables in that array are all of the same type of
data so if you’re collecting a blueprint class of let’s say can light B P then
you would create an array of data type can light be P and it would collect all
the all the objects of that type in your scene so any can light B P that you’ve
copied around in your scene and will collect that into that array a raised
from the documentation just as with variable values blueprints can store
data within arrays if you are not versed in programming terms you can think of an
array as a collection of variables all housed within a single unit so those
little nodes you see there like my bool array is a collection of both of boolean
values and it can like like it says on the
right the top right my actor array can just be a collection of various
different actors in your scene that all fit into the same type same types of
data but stored in groups instead of single into entries any variable can be
turned into an array a group or collection of the same variable type so
if you had a variable in your scene that you’re using that was Abilene you could
right click next to it where that you see that little grid of boxes and that
would turn it into an array and I’ll show you how to do that which means that
it can now hold multiple boolean values instead of just one okay now what does
all this mean well it gives us for one thing an ability to access other actors
within our scene from the blueprints of a different actor so like when we’re
taking a light switch and we want to trigger an event on that light switch
but it will access all the lights in our scene and turn them off we have to be
able to access those lights somehow so what we could do is reference it in our
blueprints using arrays and variables the first example I have written here
through arrays and variables we can reference other actors in our project by
setting up a variable or array of the data type that we want to access so this
would be can light be B or clean light blueprint then setting the value of that
variable to the specific objects so that you would collect all the can light
blueprint objects in your scene and put them into that variable or array we can
then use a get function in order to grab a reference of that object so then it
will be referencing those specific objects of that type also using the same
example still say we’re using a switch to turn off all the lights we kid within
the switch blueprint we could use a command to get all actors of a class and
I’ve showed you this we’ll talk about it more and we’ll do it more this is a
standard blueprint command and it will grab all the actors that belong to a
certain blueprint type or a class and create an array of them all from there
you can perform actions on them so again with the example within switch blueprint
you grab all the actors of a can light blueprint and set their visibility to
off when an event is true ok so these are the different ways which
we can access other objects in our scene via blueprints this will become
important when we want to interact with one thing and it affects a bunch of
other things in the following lectures you’ll see all this put into action and
it will start to make sense feel free to come back here and review the terms if
necessary and you might learn some new ones as we’re going along and you can
also go and check out some of the Yui for documentation for more about
blueprints and some of these programming terms but if you stick with me you’ll
see it all coming together and it’ll start to click for you and you have a
good basis now with some of these terms so you’ll know what I’m talking about

6 thoughts on “Unreal Engine / UE4 Basic Blueprints Tutorial: Common Terms and Concepts”

  1. Good video. The only thing that I wish to share is: [boo-lee-uh n]. This is the first time I've ever heard [boo-leen]. Just saying and otherwise good job.

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