Vec3.Dot

static float Dot(Vec3& a, Vec3& b)

   
Vec3& a First vector.
Vec3& b Second vector.
RETURNS: float The dot product!

The dot product is an extremely useful operation! One major use is to determine how similar two vectors are. If the vectors are Unit vectors (magnitude/length of 1), then the result will be 1 if the vectors are the same, -1 if they’re opposite, and a gradient in-between with 0 being perpendicular. See Freya Holmer’s excellent visualization of this concept

Examples

Pose head        = Input.Head;
Vec3 objPosition = new Vec3(0,0,-1);
bool visible     = Vec3.Dot(head.Forward, objPosition-head.position) > 0;
if (visible)
    Log.Info("Object's position is in front of the user!");