Difficulties with ladders and vector math

Unity Engine
1

Like the title states, I am having some serious trouble getting the vector math behind ladders to work exactly how I want it to. I’ll try to be as clear as possible since a video would make it far easier to explain :).

For walking I use the standard +z = forward, +y = up, +x = right as so:

desiredMove = Vector3.forward * inputVector.z + Vector3.right * inputVector.x + Vector3.up * inputVector.y;

Player movement axis:
2298720--154717--player axis.PNG

My desired functionality is that when I am on a ladder AD will only translate a player along the ladder’s x-axis, and WS will translate a player along the ladder’s y-axis. So in the following two images, I will only translate along the respective x(red) and y(green) axis for each ladder:
2298720--154719--upright axis.PNG 2298720--154718--diagonal axis.PNG

The best I’ve come up with is getting a quat to rotate my desired movement towards the up-axis of the ladder. What this didn’t do, however, is keep my sideways movement locked to the moving along the x-axis of the ladder. Any ideas of how I can get what I want?

2

If I assume a few things…

  1. code is on player
  2. player only moves left right on x-axis (player doesnt rotate)
  3. ladders are on 45* angles
speed = inputVector.x * moveSpeed;

transform.Translate(transform.forward  * speed + Vector3.up * speed);
3

Well yeah, that’s the trouble - I want the player to be able to look around while they’re on the ladder.

4

Why dont you just let the physics do it then…

5

Can’t. The whole thing is on a ship that can corkscrew through the level. And for other reasons I can’t have the ship stationary while the rest moves, or show it what’s happening via camera.

6

well that makes it complicated…

Can you clarify what you mean by ‘look around while on the ladder’. Will the player only ever walk left or right?

7

No, they can walk as a typical fps character controller. But they need to be able to continue to mouse-look while they’re going up and down on the ladder.

8

So you want the x-axis of the ladder’s transform to dictate the moving direction when they push left or right (AD), and the ladder’s y-axis dictates the moving direction when the player presses up or down (WS).

something like:

Transform ladderTransform = *a reference to the ladders transform*;
Vector2 input = new Vector2(*AD*, *WS*);
Vector3 desiredMove = ladderTransform.up * input.y + ladderTransform.right * input.x; //multiply by speed if needed
9

Finally got it. I had to manually map my input directions to the axis of the ladder object in world coordinates, then convert to my player’s local coordinates:

Vector3 ladderRight = ladder.transform.right * inputVector.x;
Vector3 ladderUp = ladder.transform.up * inputVector.z;
Vector3 ladderForward = ladder.transform.forward * inputVector.y;
desiredMove = ladderForward + ladderRight + ladderUp;
desiredMove = this.transform.InverseTransformVector(desiredMove);