Vector3
A Vector3 is a userdata that holds three values inside it. This doesn't have to be a 3D position, it could be a size as well.
The three values are an X ordinate, a Y ordinate, and a Z ordinate. They're kind of like those coordinates you use in school on graphs. I'm sure you've seen something like (1, 5) somewhere before. This means that on a graph you go to the right 1, and then up 5. That's because a coordinate uses an X and a Y value. It looks like (x, y), sometimes written as
.
This is a 2D vector, or in Roblox, a Vector2. We need a 3D vector, or Vector3. So we add another value, a Z value. This gives us (x, y, z), which can also be written as
That's really all there is to it. These numbers can be used for the Position of things, the Size of things, or anything else that needs 3 numbers to work. When people talk about the values inside a Vector3,
- X is sideways component, or width.
- Y is the vertical component, or height.
- Z is the forward component, or depth.
Using Vector3's
Moving things around
Open up a new place with a part. You might want to start with a Basic Test Map.
In the Command Bar, type in this bit here and hit enter:
game.Workspace.Part.Position = Vector3.new(0, 50, 0)
You should see that the brick moved up a good distance, you may need to move the camera to see it. What you just did is changed where the brick is, by changing it's Position. As you should know from the Absolute beginner's guide to scripting, you changed the Position by using the equal sign. You set Part.Position to a new location by using the Vector3.new constructor. You constructed a new Vector3 using 3 different values. This told the Lua engine to set the brick's Position to 0, 50, 0, making the brick move to that position.
| Property you're changing | Set To | Value you want to set it to |
| game.Workspace.Part.Position | = | Vector3.new(0, 50, 0) |
| The Position of "Part" | Set to this |
Moving things around with the Position property comes with built-in collision detection. Let's say you have a huge brick, and you try to move another brick inside of it. Instead of appearing inside of the solid brick, the second brick will pop up on top of the large one, right above where it's trying to get to. If you don't want this to happen, you can move objects around with the CFrame property instead.
Constructors
| Constructor | Description |
|---|---|
| Vector3.new(x, y, z) | Creates a new Vector3 using coordinates x, y, z. |
| Vector3.FromNormalId(Enum.NormalId normalId) | Creates a unit Vector3 in a particular facing direction. |
| Vector3.FromAxis(Enum.Axis axis) | Creates a unit Vector3 for a particular Axis. |
Methods
| Member Function | Description |
|---|---|
| Vector3:Lerp(Vector3 goal, number alpha) | Returns a Vector3 lerped between this Vector3 and the goal. Alpha should be between 0 and 1 |
| Vector3:Dot(Vector3) | Returns the vector dot product of the 2 vectors |
| Vector3:Cross(Vector3) | Returns the vector cross product of the 2 vectors |
Properties
All of these properties are Read Only (you can't just set them Vector3.x = 5, it doesn't work) but you can create new vectors with such changes, or apply an operation, seen in the next section.
| Property | Type | Description |
|---|---|---|
| Vector3.x | Number | The x-coordinate |
| Vector3.y | Number | The y-coordinate |
| Vector3.z | Number | The z-coordinate |
| Vector3.unit | Vector3 | A normalized copy of the vector |
| Vector3.magnitude | Number | The length of the vector |
Operators
| Operator | Description |
|---|---|
| Vector3 + Vector3 | returns Vector3 translated (slid) by Vector3 |
| Vector3 - Vector3 | returns Vector3 translated (slid) by -Vector3 (also gives relative position of 1 to the other) |
| Number * Vector3 | returns Vector3 with each component multiplied by Number |
| Vector3 * Number | returns Vector3 with each component multiplied by Number |
| Number / Vector3 | returns Vector3 with Number divided by each component |
| Vector3 / Number | returns Vector3 with each component divided by Number |
| Vector3 * Vector3 | returns Vector3 with each component multiplied by corresponding component |
| Vector3 / Vector3 | returns Vector3 with each component divided by corresponding component |
See CFrame for additional Vector3 operators.
Advanced Insight
In many game engine and graphics engines, a Vector3 value of (0, 0, 1) would be pointed straight up. This means that the Z axis is also pointed straight up. This is not the case in ROBLOX, where (0, 1, 0) is pointed up, that is, the Y axis.
