[Solved] Formation System - Rotate Vector3 Positions around a point?

Question

Hi there,

I'm working on a simple formation system, and thus far I am very pleased with how it turned out. However, now I would like to rotate all the Vectors around a pivot point, any ideas?

Currently I'm setting all the destinations through Vectors in a list with offsets to the point:

 private List<Vector3> TwoLineFormation(Vector3 startPoint, float spacing, Vector3 direction)
         {
             List<Vector3> targetPosList = new List<Vector3>();
             int count = selector.getSelectedNPCs().Count;
             Debug.Log(count + " NPCs selected");
             for (int i = 0; i < 2; i++)
             {
                 for (int x = 0; x <= count / 2; x++)
                 {
                     targetPosList.Add(startPoint + new Vector3(spacing / 4, 0, (spacing * x) - (spacing / 2 * count / 2) - spacing / 2));
                     targetPosList.Add(startPoint + new Vector3(-spacing / 4, 0, (spacing * x + spacing / 2) -(spacing / 2 * count / 2) - spacing / 2));
                 }
             }
             return targetPosList;
         }

As you see, I would like to use the unused variable direction for that purpose, but I'm quite unsure on how to do that.

Answer 1

Best Answer

Answer by BastianUrbach · Jan 28, 2021 at 03:20 PM

To rotate a point around a pivot, subtract the pivot, rotate the result and then add the pivot:

point = rotation * (point - pivot) + pivot;

(rotation is a Quaternion, e.g. created with Quaternion.AngleAxis or Quaternion.Euler)

Add comment · Show 2 · Share

Thison1911 · Jan 28, 2021 at 11:06 PM 0

Share

Hey thanks, I'll try it out

Thison1911 · Jan 29, 2021 at 01:41 AM 0

Share

You're a genius, it works :D

I still use a vector so I can easier use it in my project. For anyone who needs this I'll post it here:

     public static List<Vector3> LineFormation(Vector3 startPoint, float spacing, Vector3 direction)
     {
         List<Vector3> targetPosList = new List<Vector3>();
         int count = Selector.getSelectedNPCs().Count;
         Debug.Log(count + " NPCs selected");

             for (int x = 0; x <= count / 2; x++)
             {
                 Quaternion rotation = Quaternion.LookRotation(direction, Vector3.up);
                 Vector3 pointFirstRow = startPoint + new Vector3(spacing / 4, 0, (spacing * x) - (spacing / 2 * count / 2) - spacing / 2);
                 Vector3 pointSecondRow = startPoint + new Vector3(-spacing / 4, 0, (spacing * x + spacing / 2) - (spacing / 2 * count / 2) - spacing / 2);
                 targetPosList.Add(rotation * (pointFirstRow - startPoint) + startPoint);
                 targetPosList.Add(rotation * (pointSecondRow - startPoint) + startPoint);
             }
         
         return targetPosList;
     }

Basically this already is a two-row formation as a list of vectors you can assign to navmeshagents, just in case anyone needs it

Here's a demo vid https://www.youtube.com/watch?v=ADBb5OoscyI

Answer 2

Answer by itstimetomakelol · Jan 28, 2021 at 02:25 PM

Add the objects you want to pivot around to an empty gameobject with the position you want to pivot around.

For example: If you want some objects to pivot around (5, 5, 0) with a distance of 4 from the pivot point Step 1: Create an empty gameobject with the position (0, 0, 0) Step 2: Make the position of the gameobjects (4, 0, 0) (-4, 0, 0) (0, 4, 0) (0, -4, 0) (These are examples you can change it later) Step 3: Make the gameobjects children of the empty gameobject. Step 4: Move the empty gameobject to (5, 5, 0) For rotation: Rotate the empty gameobject

Not sure if this is what you want but it's something.

Code for the steps:

 private void PivotGameObjects(Vector3 pivotPoint, params GameObject[] gameObjects)
 {
     GameObject pivotObject = new GameObject("PivotObject");
     pivotObject.transform.position = pivotPoint;
     for (int i = 0; i < gameObjects.Length; i++)
     {
         gameObjects[i].transform.SetParent(pivotObject.transform);
     }
 }

Hope the code works didn't test it.

Add comment · Show 1 · Share

Thison1911 · Jan 29, 2021 at 10:16 PM 0

Share

Sorry, but that's not exactly what I was looking for. I do not use any gameObjects, only vectors to set them as destinations for my navmeshagents. But thank you very much for your effort :)

[Solved] Formation System - Rotate Vector3 Positions around a point?

2 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions