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Hello, my name is Hyunjin Kim, and I'll be teaching a basic Unreal Engine course for real-time content implementation

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In this session, we'll learn about vector subtraction

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and how to use it to make a specific actor follow another actor

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Vector subtraction

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Let's explore vector subtraction

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Now, let's create a Blueprint class in the content browser

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Right-click in the content browser, then select "blue print class"

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and choose "actor" as the base parent class

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Let's name it "bp_aiactor"

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Double-click to open it

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Let's design its appearance

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Now, in the components panel on the left, click the add button

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search for "static," and select "static mesh"

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to add a static mesh component

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Next, select the newly created static mesh component

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In the details panel, choose the appearance for the static mesh option

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Now, click on the added part to expand it

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You can choose any shape you prefer

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I'll search for "ball" in the search bar and select "sm_ball_01"

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When you press the compile button, the material for this mesh is already set up

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You can change the material to any one you prefer; feel free to select the material that suits your preference

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Let's first make this actor behave 

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by moving around after it's placed in the level

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Now, in the Event Graph

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let's use the formula p=p0 vt to make it move

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Last time, we used a similar formula p=p0 vt to move the player

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So, I'd like you to pause the video for a moment and try creating a backward movement 

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 similar to what we did last time, recalling the steps we covered

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Alright, first let's create p0

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Right-click in an empty space, then search for "Get Actor Location" and add that node

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Click to add it

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This node represents p0

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It represents the current location value

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Next, let's create v. This vector represents direction and magnitude, essentially the velocity

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To move backward, we'll need a vector in the opposite direction. We'll multiply this direction by a speed value to determine how quickly it moves

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So let's create a variable to represent the speed or velocity

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Go to the variables section, click the plus button to create a new variable

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and name it "Speed"

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Next, change the variable type to float

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Then, click the compile button, and in the details panel on the right, set the default value to 200

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Let's get the direction

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When we get the right direction, we use 'Get Actor Right Vector' by right-clicking

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Now, how do we get the forward direction?

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You do "get actor forward vector"

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Then there should be a 'Get Actor Forward Vector' that you can use to get the forward direction

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So for getting the actor's direction, you have options for the forward vector, right vector, and up vector

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How do we get the left, backward, and downward directions?

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If you multiply the right vector by minus one, it will give you the left direction

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Then, if you multiply the forward vector by -1, it will give you the backward direction

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If you multiply the up vector by -1, it will give you the downward direction

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So, when you want to get the backward direction, you can multiply the forward vector by -1 and use that

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You'll right-click again

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and search for "get actor forward vector" to add it

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And here, you'll multiply it by -1

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Drag the result of the Get Actor Forward Vector node and then multiply it by -1

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Add a Multiply node

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If you right-click in an empty space and search for "make literal float"

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you'll get a node like this

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This node simply creates a float value directly

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and you add that also

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Then, set the value here to -1

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Then, multiply the result with the forward vector

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Then, this itself becomes the backward vector

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Now, you need to multiply this by the speed value

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Take the result of multiplying the forward vector by -1, drag it into the graph

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and then search for "multiply" to add a Multiply node

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Drag the Speed variable from the left to get its value

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Let's remove that again

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When you hold down the Alt key while clicking and dragging the speed variable

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you can bring it in as a node

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that allows you to set its value

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If you hold down the Ctrl key while clicking and dragging the speed variable

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it will bring it in as a node that retrieves its value

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So, when we retrieve this speed value

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we can use a shortcut to streamline this process

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Let's remove that again

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Hold down the Ctrl key and click to bring the speed value in as a get node

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Then, connect this to the second pin here and multiply it

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Alright, now this becomes v

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Next, you need to multiply v by time

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You can multiply v by 'delta seconds'

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So, after multiplying by 'delta seconds,' drag the result

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and add another multiply node to multiply it by the speed value

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Then drag 'delta seconds' and multiply it with the result

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Double-click on the connection line to reroute it neatly without overlapping

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This then becomes

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the vt value

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Now, after adding p0 and vt together

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you can set this resulting value as the new location for this actor

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Drag the final result of vt

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then search for "add"to add an add node

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Then, connect the result from p0 to the other input of the add node to add these two values together

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So, the final result will be p

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Drag it from the add node and search for "set actor location" in the search bar to add the node

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Alright, then you just need to connect the execution pin from the event tick

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to the execution pin of the set actor location mode

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Drag the execution pin from event tick and connect it to the execution pin of set actor location

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Let's tidy up the connected lines a bit

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And then press the compile button

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Now, go to the actual level, drag bp_aiactor onto the screen, and place it

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Now, when you press the play button, you should see it moving downward as expected

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Alright, let's place one more

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Then, when you press play, you should see both of them moving in the same way

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When you create content like this

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the planning team can request to change the speed value of this moving actor

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Then we just need to change the speed value in the bpai actor

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But if we keep receiving requests to change these values

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it'll end up being extremely inefficient and time-consuming

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Therefore, we can set it up so that the planning team can continuously change these values themselves

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Next to the data tile of the speed variable we created

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there's an icon that looks like a closed eyes

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When you select that icon, it changes to an open eye icon

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In this state, click the compile button, then move the actual level

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After selecting one of the AI actors placed here

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and coming to the details window, you'll see

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that the value for speed is exposed

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within the default category like this

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After making it closed eye again

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compile it, and return to the actual level

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That item will have disappeared

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So, for variables like these

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where the planning team needs to continually test and find the appropriate values

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we expose them by opening the eye icon like this

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Then the planning team can simply change these values as needed

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I changed it to 50

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I changed the speed value of the actor placed on the right to 50

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The actor on the other side still has a speed value of 200

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So, when you press the play button

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one moves at a speed of 200, and the other moves at a speed of 50

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So, once you find the appropriate value

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you can change the default value in the bp actor to 50

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I'll change them all back to 200 for you

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I'll leave just one AI actor

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Now, when you play

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this actor moves backward

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To change this

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you'll want to make it so that the actor follows the player when the player moves

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In this case, if the player is stationary

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what direction should this actor move in?

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It should move in this direction, right?

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We want to determine this direction using vector subtraction

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Let me first illustrate vector subtraction with a diagram

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In this plane, the player is currently positioned here

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Then, our created actor is positioned here

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So, if we draw the position vectors of these two actors, it would look like this

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Let's call the red vector "a vector" and the green vector "b vector"

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Last time, we learned that adding vector a and vector b

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results in the vector connecting to this meeting point

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But this time

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let's try subtracting vector b from vector a

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Subtraction can be expressed as addition with negative values

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We can express 10 minus 3

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as adding -3 to 10

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Using the same method

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expressing a minus b as a   (-b) is equivalent

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Subtracting a vector means moving in the opposite direction of that vector

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So, -b represents a vector that has the same magnitude as the green b vector

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but points in the opposite direction

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This is the vector -b

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Let's add vector a and vector -b

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Let me connect this vector from vector a

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which has the same magnitude and opposite direction as b

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Next, if we draw a vector from the end of -b that has the same direction and magnitude as a

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they will meet at a point

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Drawing a vector that connects to this point

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will result in the sum of a and -b

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When describing vectors, if we say they have the same direction and magnitude, we mean they're the same vector

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So, if we position this vector that appears in blue here

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what result do we get?

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It shows the direction from position b towards a

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If we subtract vector a from vector b

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we'll get a vector pointing from a towards b

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Using vector subtraction like this allows us to determine the direction towards a specific location

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So, to determine the direction in which our created AI actor should face toward the player

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we'll position it like this

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The AI actor is positioned here

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and the player is positioned over there

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The AI vector

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the player position vector

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We need to determine a vector that points in this direction

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This is achieved by subtracting the AI position vector from the player position vector

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So, what I want you to understand is

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how vector addition and subtraction are represented visually

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Making a specific actor follow

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Let's make a specific actor follow 

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Let's go to the BP AI actor 

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and use subtraction to make it follow the player

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This part was about direction

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So, let's modify this part

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First, to determine the direction towards the player

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we need to know the player's position

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Yes, currently the AI actor does not know the player's position

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So, at the start, we will find the player to determine their position

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Alright, now go to the Event Begin Play section

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Right-click in the empty space 

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and search for the "Get Actor of Class" node

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Add that

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In the added node, you'll see an item labeled "Actor Class"

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If you select and expand the "Select Class" item

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you will see a list of all the classes available in Unreal

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But what class is the actor we're looking for?

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The actor we're looking for is a blueprint class called bp_player that we created

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So, if you search for bp_player here, you'll find it listed like this

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So, when you select that item

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this node will find the instance of the bp_player class in the level when we execute it

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And right at the beginning, it will find the player

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So, it informs us about the found result through the return value

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So, you can drag this return value out and place it

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If you select "Promote to Variable"

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a variable will be created in the Variables pane on the left

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The data type is "bp_player"

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We've learned four data types

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but we can also use our created classes as data types like this

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That means this variable can only hold instances created from the bp_player class

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So, let's name it "player"

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It finds the player at the start and assigns it to this variable

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Now that we've found the player, we can retrieve the player's position

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Alright, drag the player variable from the Variables section on the left

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then search for "Get Actor Location" and connect it

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Let's bring it down here for a moment

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Both of these are "Get Actor Location" nodes

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The difference between these two is whether they are connected to the player or not

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The one above is labeled as "Target: Self"

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Here, it automatically refers to itself

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But the one below is not referring to itself

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it's saying, "Hey player, give me your location"

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So, we've retrieved the player's location

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Next, we need to retrieve our own location

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Let's add another "Get Actor Location" node for the AI actor's position by right-clicking and selecting it from the menu

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We need to subtract these values

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After dragging and dropping the result of retrieving the player's location, search for "Minus" to perform subtraction

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Then you'll see "Subtract" appear

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Select "Subtract"

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and then connect the current actor's location to the second node

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Then, this result will give us the direction in which the AI actor is facing towards the player

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Now, we can make the AI actor move in this direction

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Let's write this command

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This is the direction towards the player

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So, instead of using the direction multiplied by -1 of this forward vector

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we'll use the direction that comes out from here

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So, go ahead and select and delete these three nodes

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I'll position the direction towards the player and connect it for you

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Let's tidy up the nodes a bit

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You've organized the nodes like this

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I'll represent the direction towards the player with a slightly different color

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Let's compile and play to see how it works

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00:23:40.719 --> 00:23:45.640
When you play, the AI actor disappears

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00:23:45.640 --> 00:23:51.400
It's not disappearing; rather, if you select the AI actor in the Outline

249
00:23:51.400 --> 00:23:57.560
you'll notice the location values changing rapidly

250
00:23:57.560 --> 00:24:01.079
And eventually

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00:24:01.079 --> 00:24:10.880
the blue z-value changes to "inf" or infinity

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00:24:11.760 --> 00:24:14.110
To understand this situation

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00:24:14.110 --> 00:24:19.719
a more precise understanding of vector operations is necessary

254
00:24:20.560 --> 00:24:23.800
Let's say we have 

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00:24:23.959 --> 00:24:27.579
vectors a and b on this plane

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00:24:27.579 --> 00:24:33.719
Currently, we've calculated this direction

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00:24:34.000 --> 00:24:37.100
But what we're doing here is

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00:24:37.100 --> 00:24:41.599
multiplying it by the speed value

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00:24:41.800 --> 00:24:46.760
We currently have it set to 200

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00:24:47.680 --> 00:24:54.680
Multiplying a vector of this magnitude by 200 makes it 200 times larger

261
00:24:55.119 --> 00:25:02.680
So, it results in moving a very long distance along this vector

262
00:25:02.680 --> 00:25:09.160
Thus, momentarily, the AI actor ends up positioned in this direction

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00:25:09.160 --> 00:25:12.110
Alright, what's the next step?

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00:25:12.110 --> 00:25:17.160
We'll again determine the direction in which the AI actor faces towards the player

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00:25:17.439 --> 00:25:21.359
So, we're calculating this direction

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00:25:21.920 --> 00:25:26.400
Here, we're multiplying it by 200

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00:25:26.400 --> 00:25:29.350
We're already moving with such a large vector

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00:25:29.350 --> 00:25:31.479
and now we're multiplying it by an additional factor of 200

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00:25:31.479 --> 00:25:34.079
Then it will become extremely large once again

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00:25:34.079 --> 00:25:39.239
We're currently repeating this logic

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00:25:39.239 --> 00:25:43.760
So, what we need to do to modify this is

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00:25:48.800 --> 00:25:57.160
to normalize the direction vector after calculating it

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00:25:57.160 --> 00:26:01.310
So, we're creating a vector like this

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00:26:01.310 --> 00:26:05.199
Here, we're multiplying it by speed

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00:26:05.199 --> 00:26:11.239
and then by time

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00:26:11.319 --> 00:26:18.000
That way, we achieve the movement speed we desire

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00:26:18.520 --> 00:26:26.680
Normalizing a vector to have a magnitude of 1 is called vector normalization

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00:26:27.359 --> 00:26:30.560
It's called normalization, often referred to as "normalize"

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00:26:34.640 --> 00:26:41.800
So, we used vector subtraction to find the direction towards the player

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00:26:41.800 --> 00:26:48.920
Now, we'll normalize this vector to make its magnitude 1

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Let's go back to the BP AI actor

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00:26:53.199 --> 00:26:59.400
and handle the direction towards the player 

283
00:27:00.239 --> 00:27:02.760
without directly multiplying the calculated result

284
00:27:05.239 --> 00:27:11.920
I'll search for "normalize" by using this result value again

285
00:27:11.920 --> 00:27:15.770
Then, there should be one "normalize" at the top

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00:27:15.770 --> 00:27:18.920
Add the corresponding node

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00:27:18.920 --> 00:27:23.470
Then, connect that result value

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00:27:23.470 --> 00:27:25.880
By doing this

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00:27:25.880 --> 00:27:33.719
the magnitude of the direction towards the player will be changed to 1 and returned

290
00:27:34.680 --> 00:27:38.080
Now, after compiling and playing

291
00:27:38.080 --> 00:27:47.119
you'll see that the actor will follow the player like this

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00:27:49.920 --> 00:27:58.479
Let's modify the current node a bit to make it move in a different way

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00:27:58.479 --> 00:28:04.640
First, let's temporarily disconnect the part that finds the player in the Begin Play event

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00:28:04.640 --> 00:28:08.280
Next, let's create a new variable

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00:28:08.280 --> 00:28:11.130
Please click on the plus button in the Variables section

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00:28:11.130 --> 00:28:14.920
Name it "target"

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00:28:15.359 --> 00:28:21.880
Next, if you search for "Actor" under object types

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00:28:21.880 --> 00:28:27.680
you'll find it like this

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00:28:27.680 --> 00:28:29.419
Selecting that option 

300
00:28:29.419 --> 00:28:35.760
will set the data type to "Actor" like this

301
00:28:36.160 --> 00:28:43.439
So, now the "target" variable is capable of storing an actor

302
00:28:44.280 --> 00:28:48.680
Let's temporarily disconnect the "Get Player" node

303
00:28:48.680 --> 00:28:52.789
in the part where we calculate the direction towards the player in the Event Tick

304
00:28:52.789 --> 00:29:00.640
Now, let's drag and use the "target" variable that we created earlier with a "Get" node

305
00:29:01.920 --> 00:29:05.720
So, you've changed it to calculate the direction

306
00:29:05.720 --> 00:29:11.800
towards the position of this "target" using its location

307
00:29:12.000 --> 00:29:17.450
Then, click on the eye icon next to the "target" variable

308
00:29:17.450 --> 00:29:19.680
to make it visible

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00:29:19.680 --> 00:29:24.640
and expose it in the details pane

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00:29:24.640 --> 00:29:29.839
Compile and move to the actual level

311
00:29:29.839 --> 00:29:35.839
After selecting the bpai actor, if you look in the details pane

312
00:29:35.839 --> 00:29:39.119
you'll see that the "target" is currently set to "None."

313
00:29:39.119 --> 00:29:42.169
It means that currently, the "target" variable does not have any value assigned to it

314
00:29:42.169 --> 00:29:46.040
If you play in this state, what will happen is that

315
00:29:46.040 --> 00:29:48.190
an error will occur

316
00:29:48.190 --> 00:29:54.000
because the target variable is not assigned a value

317
00:29:54.000 --> 00:30:00.719
so asking for the position of something that doesn't exist causes an error

318
00:30:00.839 --> 00:30:07.119
When we were making the actor chase the player earlier

319
00:30:07.119 --> 00:30:12.760
we assigned a value to the "player" variable at the start

320
00:30:13.160 --> 00:30:21.319
So, when we instructed it to move towards the direction of the player, there were no errors

321
00:30:21.319 --> 00:30:23.819
If you play in the current state

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00:30:23.819 --> 00:30:29.119
you'll see that an error occurs like this

323
00:30:30.919 --> 00:30:33.769
So, if you click on "None" next to "target"

324
00:30:33.769 --> 00:30:39.039
you'll see a list of all the actors currently placed in this level

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00:30:39.039 --> 00:30:43.719
This means that all the actors listed in the Outliner here will be shown

326
00:30:43.719 --> 00:30:50.520
Because everything placed in this level is an actor, that's why you see all the actors listed there

327
00:30:50.640 --> 00:30:59.079
Now, if you select "BP Player" here, it should behave the same way as before

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00:30:59.439 --> 00:31:02.849
Because now the "target" variable contains something—it contains the player

329
00:31:02.849 --> 00:31:06.959
Now it should be functioning to chase after the player

330
00:31:06.959 --> 00:31:09.709
If you play now

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00:31:09.709 --> 00:31:12.920
it should continue to chase after the player

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00:31:13.680 --> 00:31:21.520
Go ahead and copy the BP AI actor while holding down the Alt key, then place it where you want

333
00:31:21.880 --> 00:31:25.830
Now with both of these BP AI actors placed

334
00:31:25.830 --> 00:31:31.280
they should both be chasing after the player

335
00:31:31.959 --> 00:31:34.809
 Let's go ahead and change some of the values here

336
00:31:34.809 --> 00:31:43.350
Set the speed value for the BP AI actor on the left to 350

337
00:31:43.350 --> 00:31:46.959
and set the "target" to BP Player for that actor

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00:31:46.959 --> 00:31:54.640
Then, set the speed for the BP AI actor on the right to 300

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00:31:54.640 --> 00:32:01.439
and set its target to the BP AI actor on the left

340
00:32:01.439 --> 00:32:06.239
So, you're selecting this BP AI actor

341
00:32:06.239 --> 00:32:10.460
Let's make some predictions before pressing the play button

342
00:32:10.460 --> 00:32:17.310
The AI actor on the left has the player as its target, correct?

343
00:32:17.310 --> 00:32:21.640
So, this actor will be chasing after the player

344
00:32:21.640 --> 00:32:30.119
But the actor on the right has its target set to the BP AI actor on the left

345
00:32:30.119 --> 00:32:32.769
Therefore, this actor won't chase after the player

346
00:32:32.769 --> 00:32:38.680
instead, it will start chasing after the AI actor on the left

347
00:32:38.680 --> 00:32:47.560
If you play now, you should see them following each other in a chase-like manner

348
00:32:48.460 --> 00:32:50.520
Let's add one more here

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00:32:50.520 --> 00:32:53.320
Copy it again by holding Alt

350
00:32:53.320 --> 00:32:57.319
and this time set the speed to 250

351
00:32:57.319 --> 00:33:05.119
Set the target of the newly added actor to BP AI Actor 2

352
00:33:05.560 --> 00:33:07.860
If you play now

353
00:33:07.860 --> 00:33:13.359
you should see them moving in a chain-like formation, chasing each other

354
00:33:14.359 --> 00:33:20.800
If you apply this in a slightly different way

355
00:33:20.800 --> 00:33:25.560
you can create various other forms of movement

356
00:33:26.319 --> 00:33:30.869
So, during your personal study time

357
00:33:30.889 --> 00:33:36.199
I hope you try applying it in various ways

358
00:33:36.359 --> 00:33:44.439
Alright, I'll modify this code to revert back to the blueprint nodes originally used to chase the player

359
00:33:44.439 --> 00:33:47.389
Remove this target 

360
00:33:47.389 --> 00:33:51.359
and then you should connect it to the player like this

361
00:33:51.719 --> 00:33:58.319
Next, make sure to connect the node that was in Begin Play so that it runs when executed

362
00:33:58.680 --> 00:34:05.079
Select and delete the variable that was created for the target as well

363
00:34:07.119 --> 00:34:15.120
Then, after moving to the actual level, select and delete the two additional actors that were added

364
00:34:15.120 --> 00:34:22.040
Let's play again to verify that everything is functioning correctly

365
00:34:24.560 --> 00:34:31.529
This time, let's modify it so that it calculates the direction based on the initial position when it starts

366
00:34:31.529 --> 00:34:38.879
and then moves only in that initial direction regardless of where the player moves

367
00:34:38.879 --> 00:34:43.379
The reason the BP AI actor

368
00:34:43.379 --> 00:34:46.399
keeps following the player is because

369
00:34:46.399 --> 00:34:54.679
the Event Tick node updates its direction each time it runs

370
00:34:54.679 --> 00:34:59.369
If we set it up so that we calculate the direction only once at the start 

371
00:34:59.369 --> 00:35:03.000
and then move in that direction continuously

372
00:35:03.000 --> 00:35:07.479
the actor won't follow the player even if the player moves

373
00:35:08.000 --> 00:35:15.520
So, let's disconnect these nodes that calculate the direction towards the player

374
00:35:15.520 --> 00:35:19.639
and bring this into the Begin Play event

375
00:35:20.639 --> 00:35:29.360
Then, we'll create a variable to store the result of this direction calculation

376
00:35:29.360 --> 00:35:34.120
So, you'll drag the normalized result 

377
00:35:34.120 --> 00:35:39.770
and use "Promote to Variable" to create a variable from it

378
00:35:39.770 --> 00:35:43.280
Name it "dir"

379
00:35:43.280 --> 00:35:50.399
For the variable type, it should automatically be selected as "Vector" for data purposes

380
00:35:50.399 --> 00:35:59.320
Then, connect it so that it runs after finding the player

381
00:35:59.320 --> 00:36:06.719
Then, upon starting, the dir variable should contain the direction towards the player

382
00:36:06.719 --> 00:36:10.600
Now, let's come back down to the Event Tick

383
00:36:10.800 --> 00:36:16.250
Then, you get this dir variable using get

384
00:36:16.250 --> 00:36:21.719
connect it like this, and you're done

385
00:36:23.840 --> 00:36:30.959
And then, after compiling, go to the actual level and play

386
00:36:31.399 --> 00:36:34.009
and it will move towards the player like this

387
00:36:34.009 --> 00:36:37.919
Then, play again and try moving the player

388
00:36:37.919 --> 00:36:39.469
it won't keep following

389
00:36:39.469 --> 00:36:45.520
you can see that it only moves in the direction that was initially set

390
00:36:45.520 --> 00:36:49.220
I'll try moving the player further to the right

391
00:36:50.020 --> 00:36:53.550
Then, although this AI actor previously moved in this direction

392
00:36:53.550 --> 00:36:59.199
this time, it will come towards the new position

393
00:36:59.199 --> 00:37:01.460
Let's try playing it

394
00:37:01.460 --> 00:37:07.879
Even if you move the position, it will still move in the direction calculated initially, right?

395
00:37:07.959 --> 00:37:13.760
So, you can confirm that the actor's movement varies

396
00:37:13.760 --> 00:37:20.400
depending on whether you calculated the direction towards the player

397
00:37:20.400 --> 00:37:26.199
in the Begin Play or in the Event Tick node

398
00:37:26.199 --> 00:37:29.109
I'll tell you about a new node

399
00:37:29.109 --> 00:37:33.879
So, in Begin Play, we're currently locating the player

400
00:37:39.179 --> 00:37:43.439
And then we proceed to perform some other action, right?

401
00:37:43.439 --> 00:37:45.389
First, we find the player

402
00:37:45.389 --> 00:37:49.399
and then we calculate the direction towards the player

403
00:37:49.399 --> 00:37:51.649
Then we need to do something else afterward

404
00:37:51.649 --> 00:37:54.879
So, we need to connect another execution pin at the end, right?

405
00:37:54.879 --> 00:37:57.579
If this increases, what will happen?

406
00:37:57.579 --> 00:38:03.159
It will continue with nodes being connected one after another like a chain

407
00:38:03.159 --> 00:38:07.439
As it continues like that, it might become less readable or inconvenient to navigate

408
00:38:07.439 --> 00:38:12.439
So, there's a blueprint node called "Sequence"

409
00:38:12.439 --> 00:38:18.850
Alright, if you right-click and search for "Sequence"

410
00:38:18.850 --> 00:38:20.900
you'll find a node for it

411
00:38:20.900 --> 00:38:25.159
When you add a Sequence node, it looks like this

412
00:38:25.159 --> 00:38:28.739
It determines the order in which actions are executed

413
00:38:28.739 --> 00:38:31.789
So it executes the first action as 0

414
00:38:31.789 --> 00:38:35.930
and once that's finished, it moves on to execute the second action as 1

415
00:38:36.230 --> 00:38:41.640
So, instead of directly finding the player in Begin Play

416
00:38:41.640 --> 00:38:47.980
we'll disconnect and use this Sequence node to execute actions in order

417
00:38:47.980 --> 00:38:51.630
In Begin Play, after connecting to the Sequence node

418
00:38:51.630 --> 00:38:55.159
we link the first task that needs to be performed

419
00:38:55.159 --> 00:38:59.000
Please also delete the connections from this node

420
00:39:02.420 --> 00:39:08.360
Then, connect the second task that needs to be done to "Then 1" on this side

421
00:39:12.719 --> 00:39:15.569
Using the Sequence node allows you to sequentially proceed

422
00:39:15.569 --> 00:39:20.000
with finding the player

423
00:39:20.000 --> 00:39:23.140
and then calculating the direction towards the player

424
00:39:23.140 --> 00:39:25.190
If you want to do more

425
00:39:25.190 --> 00:39:28.800
you can click the "Add Pin" button here

426
00:39:28.800 --> 00:39:37.439
which will add another execution pin so you can connect the next node that should be executed in sequence

427
00:39:38.239 --> 00:39:40.739
If you don't need it, you can right-click

428
00:39:40.739 --> 00:39:45.760
and select "Remove Execution Pin"

429
00:39:45.760 --> 00:39:49.000
to make that pin disappear

430
00:39:49.679 --> 00:39:57.360
So, now we can organize nodes more intuitively using the Sequence node

431
00:39:58.520 --> 00:40:02.460
Let's summarize what we've learned in this session

432
00:40:02.460 --> 00:40:09.120
We've learned that using vector subtraction allows you to determine the direction towards a specific actor

433
00:40:09.120 --> 00:40:15.120
We've learned how to use vector subtraction to continuously follow a specific actor

434
00:40:15.120 --> 00:40:20.870
And executing the functionality to determine the direction towards the actor in the tick node

435
00:40:20.870 --> 00:40:23.360
allows the actor to continuously follow it

436
00:40:23.360 --> 00:40:25.790
We've learned that executing this in the Begin Play node 

437
00:40:25.790 --> 00:40:29.890
sets the actor's direction once based on the initial position

438
00:40:29.890 --> 00:40:33.399
and moves in that direction continuously

439
00:40:33.659 --> 00:40:36.019
Vector subtraction
Direction Vector: Right Get Actor Right Vector

440
00:40:36.019 --> 00:40:38.426
Forward Vector: Get Actor Forward Vector
Left: Right Vector * -1
Backward: Forward Vector * -1

441
00:40:38.426 --> 00:40:40.626
Using vector subtraction to determine the direction towards a specific location

442
00:40:40.626 --> 00:40:42.926
Making a specific actor follow
Normalizing vectors
Making the vector size 1

443
00:40:42.926 --> 00:40:45.226
Functionality of nodes for determining actor direction
Event Tick Node: Continuously follows the actor
Begin Play Node: Sets direction once and moves in that direction continuously


444
00:40:45.226 --> 00:40:47.646
Determining execution order
Sequence node