CODEWITHSUNDEEP
c#unity-game-engine
DeveloperApps
DeveloperApps

Reputation: 803

Rotate an object to a line between 2 points

I have a line between two points (Vector3) V1 - V2

I add an object on this line but initially it is always horizontal as in the picture on the left

It is a mesh object - IMPORTANT

How do I rotate this object to be along this line as in the picture on the right?

IMPORTANT to rotate every point in this mesh (not an object)

For further work, I need the exact locations of all the vertices

I try something like this but it's not the way to go:

Vector3 v = V2 - V1;
Quaternion rotation = Quaternion.LookRotation(v, new Vector3(1, 1, 0));
rotation *= Quaternion.Euler(0, 90, 0);


// I rotate all the points in the mesh
for (int i = 0; i < vertices.Length; i++)
{
     vertices[i] = RotatePointAroundAxis(vertices[i], pos, Vector3.up, rotation.eulerAngles.y);
}

public Vector3 RotatePointAroundAxis(Vector3 pointToRotate, Vector3 centerAxis, Vector3 axis, float angle)
{
     Vector3 point = Quaternion.AngleAxis(angle, axis) * (pointToRotate - centerAxis);
     Vector3 result = centerAxis + point;
     return result;
 }

enter image description here

Upvotes: 0

Views: 555

Answers (1)

derHugo
derHugo

Reputation: 90580

It is way easier simply using

Vector3 v = V2 - V1;
yourObject.transform.right = v;

or if you want to go for one of the other axes

yourObject.transform.forward = v;

or accordingly

yourObject.transform.up = v;

depending on your use case and desired result

After your Update I see you want/need it rather on mesh basis.

Here I would use a Matrix like e.g.

var deltaRotation = Quaternion.FromToRotation(Vector3.right, v);
var matrix = Matrix4x4.TRS(Vector3.zero, deltaRotation, Vector3.one);

var verts = mesh.verts;
for(var i = 0; i< verts.Length; i++)
{
    verts[i] = matrix.MultiplyPoint3x4(verts[i]);
}
mesh.verts = verts;

again if needed change the Vector3.right to Vector3.forward or Vector3.up etc accordingly.

Upvotes: 1

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