DeprojectScreenPositionToWorld — convert 2D screen coords to 3D world ray

APlayerController method. WorldDirection is the ray direction for line traces.

DeprojectScreenToWorld — convert 2D screen position to 3D world ray

Pure node. WorldDirection is the ray direction — multiply by large number and add WorldLocation to get the trace end point for mouse-to-world ray casting.

Rotator

A 3D rotation (Pitch, Yaw, Roll) in degrees. Combine with Vector for full positioning.

Vector

A 3D point or direction (X, Y, Z). Used for positions, directions, scales. Z is up by default in UE.

PlaySoundAtLocation — play a 3D positional sound at a world location

ProjectWorldLocationToScreen — project 3D location to 2D screen coordinates

APlayerController method.

Skeletal Mesh

A 3D model with a skeleton — can be animated. Used for characters and creatures.

SceneComponent

A component with a Transform — can be attached and positioned in 3D. Static Mesh and Camera inherit from it.

Static Mesh

A non-deforming 3D model (rocks, walls, props). Cheap to render. For animated meshes use Skeletal Mesh.

SetActorScale3D — set actor world scale

NOT K2_ prefixed (unlike SetActorLocation/Rotation).