I want to rotate a plane towards a normal of 3 Vectors/Points

Questions & Answers
1

Hi!
Im am trying to create a plane that is defined by 3 points, one of them you can reposition with your mouse. The other is calculated so that the 3 Points form a plane that is tangent to a cone.

I don’t know how to create a plane that has those three points/Vectors (like this)

179419-1.png
179419-1.png1239×601 256 KB

What I tried to do was get the normal of these three points (point v, point p, point t)
and set the rotation of the plane to that normal pointing towards the top of the plane:

179421-2.png
179421-2.png1423×498 94.9 KB

The result I get from this, is the plane switching between the intended rotation and reset rotation every frame.
here is the whole code:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class TangentPlane : MonoBehaviour
{
    //Point Vectors
    public Vector3 tPoint;
    public Vector3 vPoint;
    public Vector3 pPoint;

    private Vector3 sideA;
    private Vector3 SideB;

    public Vector3 planeNormal;

    // Horizontal Plane
    private GameObject TangentEquation;
    private bool horizontalPlane;
    private bool perfilTangent;

    void Update()
    {
        //Horizontal Plane
        TangentEquation = GameObject.FindGameObjectWithTag("Tangent");
        horizontalPlane = TangentEquation.GetComponent<TangentEquation>().horizontalPlane;
        perfilTangent = TangentEquation.GetComponent<TangentEquation>().perfilTangent;

        //Points
        tPoint = GameObject.FindGameObjectWithTag("Tangent").transform.position;
        vPoint = GameObject.FindGameObjectWithTag("VPoint").transform.position;
        pPoint = GameObject.FindGameObjectWithTag("P").transform.position;
        
        // Establish the difference betwen points
        sideA = tPoint - vPoint;
        SideB = pPoint - vPoint;

        //calculate the normal
        planeNormal = (Vector3.Cross(sideA, SideB)).normalized;

        transform.rotation = Quaternion.FromToRotation(transform.up, planeNormal);
        
        if(Input.GetMouseButtonUp(0))
        {
            if (horizontalPlane == true)
            { }
            else if (perfilTangent == true)
            { }
            else
            {
            }
        }
    }
}

Blockquote

2

If you edit this code transform.rotation = Quaternion.FromToRotation(transform.up, planeNormal);

For this
transform.rotation = Quaternion.FromToRotation(transform.position, planeNormal);

You get the desired result :slight_smile: