Rotation Problem

Hi how do I make "This " rotate around "That" on the image.

Thanks

 

There might be a unity solution, but here a c# solution:

///variable in class
public float alpha=0f; //this is the arc
public float rotspeed=1.23; //rotation speed

Start(){
//pseudocode, you need to get the position the two objects; this code is for case the pc doesnt move in game
pc=position of center object;
po=position of circulating object; (initiale position should be the distance you want to have to center object);
}
Update(){
alpha+=Time.deltaTime*rotspeed; //increment arc
po=pc+Rotation2D(po-pc, alpha); //set new position
}

private Vector2 Rotation2D(Vector2 v, float angle)
{
float rad = (angle / 180) * Mathf.PI;
float c = Mathf.Cos(rad);
float s = Mathf.Sin(rad);

return new Vector2(c * v.x - s * v.y, s * v.x + c * v.y); //rotation Matrix 2D
}

Haven't tested the code, but Rotation2D works proper.

 

I have to correct, ther might not be a unity solution, there is a unity solution.

 

You could make the white circle a child of the red circle, position the white circle wherever desired, then rotate the red circle.

 

Yep, create a parent/child relationship like Cucci_A wrote above.