Your camera is at an angle and you’re using the length of the springarm to multiply the directional vector - that will not play well, you’re running out of vector.
You have options:
- line trace:
You need need a long enough vector to reach the floor visible at the very top end of the screen. And the springarm is nowhere nearly long enough for that - it only reaches your character. Using a fixed distance is fine for this.
- get hit under cursor:
- there’s also Line Plane Intersection but it seems that you do want to hit the ground here, so it may not be the best option/