Make It Move

What you'll learn

• What a CharacterBody3D is and why players use it
• How a game reads the keyboard with Input
• What velocity (speed + direction) means
• The difference between _ready (once) and _physics_process (every frame)

Part 1 — Rebuild the player

1. Delete the old player

   Right-click the old Player (the plain box) in the Scene panel → Delete Node(s). Don't worry, we're building a better one.

2. Add a CharacterBody3D

   Select World → + Add Child Node → CharacterBody3D. Rename it Player. You'll notice a yellow warning triangle next to it — that's normal, it just means "I need a body shape", which we add next.

3. Give it a shape it can see (mesh)

   Select Player → Add Child Node → MeshInstance3D → give it a New BoxMesh. This is the bit you'll see on screen.

4. Give it a shape it can feel (collision)

   Select Player again → Add Child Node → CollisionShape3D → in the Inspector set its Shape to New BoxShape3D. This invisible box is how the player physically bumps into the world. The warning triangle disappears.

5. Lift the player up

   Select Player and set Position Y to 1 so it starts above the floor.

Part 2 — Give the player a script

1. Attach a script to the Player

   Right-click Player → Attach Script → Create. Godot gives you a starter file made for a CharacterBody3D.

2. Replace it with this

   Delete what's there and type this in. Take your time — every line is explained just below.

   extends CharacterBody3D
   
   # How fast the player moves
   var speed = 5.0
   
   
   func _physics_process(delta):
   	# Start with no movement
   	var direction = Vector3.ZERO
   
   	# Check which arrow keys are held down
   	if Input.is_action_pressed("ui_up"):
   		direction.z -= 1
   	if Input.is_action_pressed("ui_down"):
   		direction.z += 1
   	if Input.is_action_pressed("ui_left"):
   		direction.x -= 1
   	if Input.is_action_pressed("ui_right"):
   		direction.x += 1
   
   	# Turn that direction into actual speed, then move
   	velocity = direction * speed
   	move_and_slide()

   The arrow keys already work in Godot out of the box — they're called ui_up, ui_down, ui_left and ui_right.

3. Run it

   Press F5 and hold the arrow keys. Your box slides around the field. 🎉

Understand it — line by line

extends CharacterBody3D

Yesterday's scripts extended Node. This one belongs to a CharacterBody3D, which unlocks special powers like velocity and move_and_slide() that a plain node doesn't have.

var speed = 5.0

A var (variable) is a labelled box that stores a value. Here the box is called speed and holds the number 5. Because it's a variable, you can change movement speed for the whole game by editing this one number — that's exactly why we use variables instead of scattering the number 5 everywhere.

func _physics_process(delta):

_ready (from Day 1) runs once at the start. _physics_process is different — Godot runs it about 60 times every second, over and over. That constant repeating is what lets movement feel smooth and live. The delta in the brackets is "how long since the last run" — we'll use it properly tomorrow.

var direction = Vector3.ZERO

A Vector3 is just three numbers bundled together — an X, a Y and a Z — perfect for describing a direction in 3D. Vector3.ZERO means (0, 0, 0): no movement at all. We start from "not moving" each frame, then add to it.

The four if blocks

if means "only do the next bit if something is true". Input.is_action_pressed("ui_up") asks "is the up arrow held down right now?". If yes, we nudge the direction's Z by -1 (forward). Hold two keys and you move diagonally, because both ifs run. This is how nearly all keyboard control works.

velocity = direction * speed then move_and_slide()

Velocity means speed-with-a-direction. We take the direction (which way) and multiply by speed (how fast) to get the final velocity. Then move_and_slide() is the CharacterBody3D's built-in command that actually moves the player and slides nicely along walls instead of getting stuck. You set the velocity; Godot does the moving.

Play around — level up 🎮

If something went wrong

"Red error mentioning 'velocity' or 'move_and_slide'." The first line must be extends CharacterBody3D (not Node). Those powers only exist on a CharacterBody3D.

"It won't run — error about indentation." The lines inside the if blocks need two Tabs (one for the function, one for the if). Match the spacing in the example exactly.

"The box moves but falls through / floats oddly." That's fine for today — we have no gravity yet. Tomorrow fixes it. Just make sure Player's Position Y is 1.

"Arrows don't do anything." Make sure the script is attached to the Player node (a little scroll icon shows next to it) and that you pressed Play, not just saved.

Tomorrow: gravity and jumping — your player learns to fall and leap. 🦘