To make a billboard which rotate around a axis

Questions & Answers
1

How to make a billboard which can rotate around a axis automatically,like the lineRenderer of Unity.

[6863-qq截图20130119132044.jpg|6863] the line renderer!

Have tried everything I can and still can’t complete it.Can anybody help me?

Much appreciated first!!

2

If you want a billboard to face the main camera:

  billboardObject.transform.forward = -Camera.main.transform.forward;

Preferably caching the transforms of those two things for perfomance

3

@username Bit of a necrobump but for a good answer:

//*****************************************************
//                <<<Class Purpose>>>
// Enable the creation of billboards for 2D graphics
// in 3D space. Choice of flat, spherical or arbitrary
// axis aligned billboards. Corrects for camera roll.
//*****************************************************
 
 
// Using namespaces
using UnityEngine;
 
public class A3DBillboard : MonoBehaviour {
 
    //*** CONSTANTS ***
    public enum A3DBillboardType
    {
        Flat,      // Inverse camera rotation
        Sphere,    // Looks directly at camera
        Axial      // Swivels around defined axis
    }
 
    //*** INSPECTOR FIELDS ***
 
    [SerializeField] private Vector3 _vAxis = Vector3.up;                                   // Axis for arbitrary rotation
    [SerializeField] private A3DBillboardType _billboard = A3DBillboardType.Sphere;         // Test if pitch control is clamped
    [SerializeField] private bool _correctRoll = true;                                      // Correct for camera roll
 
    //*** LOCAL VARIABLES ***
    private Vector3 vLook;                  // constructed billboard forward vector
    private Vector3 vRight;                 // constructed billboard right vector
    private Vector3 vUp;                    // constructed billboard up vector
 
    private Transform billboardTransform;   // link to billboard object transform
    private Transform cameraTransform;      // link to camera object transform
 
 
    // Use this for initialization
    void Start()
    {
        billboardTransform = this.transform;
        cameraTransform = Camera.main.transform;
    }
 
    // Update is called once per frame
    void LateUpdate()
    {
        if (_billboard == A3DBillboardType.Flat)
        {
            // Flat billboards opposite rotation to camera
            billboardTransform.rotation = Quaternion.LookRotation(cameraTransform.forward, cameraTransform.up);
 
            // Check if correct for camera roll
            if (_correctRoll)
            {
                Vector3 CameraRotation = cameraTransform.eulerAngles;
                if (CameraRotation.z != 0) { billboardTransform.Rotate(0f, 0f, -CameraRotation.z); }
            }
        }
        else if (_billboard == A3DBillboardType.Sphere)
        {
            // Spherical billboards look at camera position
            //MyTransform.LookAt(MyCameraTransform.position, MyCameraTransform.up);
            //MyTransform.Rotate(new Vector3(0f, 180f, 0f));
 
 
            // create billboard look vector
            vLook = billboardTransform.position - cameraTransform.position;
            vLook.Normalize();
 
            // create billboard right vector
            vRight = Vector3.Cross(cameraTransform.up, vLook);
 
            // create billboard up vector
            vUp = Vector3.Cross(vLook, vRight);
 
            // spherical billboard with look direction towards camera
            billboardTransform.rotation = Quaternion.LookRotation(vLook, vUp);
 
            // Check if correct for camera roll
            if (_correctRoll)
            {
                Vector3 CameraRotation = cameraTransform.eulerAngles;
                if (CameraRotation.z != 0) { billboardTransform.Rotate(0f, 0f, -CameraRotation.z); }
            }
 
            // create the billboard matrix
            // M = D3DIdentityMatrix()
            // M.rc11 = vRight.X: M.rc12 = vRight.Y: M.rc13 = vRight.z
            // M.rc21 = vUp.X: M.rc22 = vUp.Y: M.rc23 = vUp.z
            // M.rc31 = vLook.X: M.rc32 = vLook.Y: M.rc33 = vLook.z
        }
        else if (_billboard == A3DBillboardType.Axial)
        {
            //create temporary billboard look vector
            vLook = billboardTransform.position - cameraTransform.position;
            vLook.Normalize();
 
            //create billboard right vector
            float visible = Mathf.Abs(Vector3.Dot(_vAxis, vLook));
            if (visible >= 1)
            {
                // look vector is parallel to axis
                vLook = _vAxis;
            }
            else
            {
                // create and normalize right vector
                vRight = Vector3.Cross(_vAxis, vLook);
                vRight.Normalize();
 
                // create final billboard look vector
                vLook = Vector3.Cross(vRight, _vAxis);
 
                // create billboard up vector
                vUp = Vector3.Cross(vLook, vRight);
 
                // axial billboard with look rotation axis aligned
                billboardTransform.rotation = Quaternion.LookRotation(vLook, vUp);
            }
 
            // create the billboard matrix
            // M = D3DIdentityMatrix()
            // M.rc11 = vRight.X: M.rc12 = vRight.Y: M.rc13 = vRight.z
            // M.rc21 = vAxis.X: M.rc22 = vAxis.Y: M.rc23 = vAxis.z
            // M.rc31 = vLook.X: M.rc32 = vLook.Y: M.rc33 = vLook.z
        }
    }