I am new to Unreal. I only started learning about a week ago and my curiosity is getting to me. While learning to program basic animation and damage events I ran into vectors. I could accept they are magic but I would like to understand better the vector data type and specifically what "Get Forward Vector " returns when referencing a player character. The Forum post I have already looked into a bit is here What Is A Forward/Up/Etc Vector?. Beyond any information you guys can give me if there is a good resource to understand the programming of these different classes and functions please let me know.
Hey
Vectors in this case (3 point vectors) are just coordinates or data that stores X, Y, Z values.
ForwardVector, UpVector and RightVector are quite simple:
By default, when everything is at 0,0,0 (rotation), the vectors would look like this
- Forward: X:1, Y:0, Z:0
- Up: X:0, Y:0, Z:1
- Right: X:0, Y:1, Z:0
When you use GetForwardVector, what it does internally is taking the actor’s rotation and convert it to a normalized X,Y,Z vector only with the Forward direction.
The horizontal axis, as you can infer from the information above are only X and Y, so a ForwardVector will only have horizontal information as well as a RightVector. On the same way, an UpVector will only have vetical information.
Obviously, if the actor is rotated in “unusual” angles, the vectors will have data on different axis.
Why are the directional vectors normalized? Precisely because they’re just directions, so the sum of all the values of the vector can never be more or less than 1.
→ Example: X:0.53, Y:0.47, Z:0
Rotations work differently. A rotator doesn’t represent X,Y,Z in the same way. In rotations, Z is the horizontal axis. That’s why, for a direction, you need to process it into a Vector.
Hope this helps
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Hey there @ArcticCat2008! Welcome to the community! So depending on how deep you want this explanation (ie Unreal Engine’s implementation specifically or Vector Math et al), the answer could get very scholarly.
The oversimplified explanation is that an object’s local vectors (ie forward/up/right etc) are defined on the object. For example, your root object from a fresh Actor class will have it’s forward vector as X, up as Z, and right as Y all of length 1 according to the source code.
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Unreal Vector explanation:
Vectors as Math:
