Make object stand up after thrown on the floor?

Hello,

I am currently trying to make an object stand up (rotate) from laying down on the floor. I tried to achieve that with the following rotations:

Code (csharp):

1.  
2. public void standUp ()
3.     {
4.         Quaternion startRotation = transform.rotation;
5.         Quaternion endRotation = Quaternion.Euler(0, startRotation.y, 0);      
6.         transform.rotation = Quaternion.Slerp(startRotation, endRotation, Time.deltaTime*2.0F);    
7.     }
8.  

While this works, the object always rotates into the default rotation which is that the Y (the Up-Axis) is rotated looking into the Z-direction (the default direction when an object is created). However, what I want to achieve is that when it stands up, it should keep the rotation of the Y-Axis. Any hints on that?

 

Ok I think got it. For the record: the trick is to keep the specific values of the rotation before standing up (Y-Value and W-Value) and set the others to 0:

Code (csharp):

1.  
2. Quaternion startRotation = transform.rotation;
3. Quaternion endRotation = new Quaternion (0.0F,transform.rotation.y,0.0F,transform.rotation.w);
4. transform.rotation = Quaternion.Slerp(startRotation, endRotation, Time.deltaTime*2.0F);

 

Hey thanks! I had exactly the same problem, and thanks to you i solved it!

 

Thanks, that was the most clear answer.

 

So, can i just put the code in a every update, and it will work?

 

There is absolutely no need to tweak the quat values if you don't know what you're doing.

You should simply Slerp between two directions.
First you save the original object's up direction with

myObject.transform.up

Then you can tween the rotation between this source direction to the target direction, which is Vector3.up

Code (csharp):

1. // this finds the shortest path between two directions
2. currentDir = Vector3.Slerp(startDir, Vector3.up, t));
3.  
4. // then you use the computed direction and make a rotation quat from the currentDir
5. Quaternion tweened = Quaternion.FromToRotation(myObject.transform.up, currentDir);
6.  
7. // finally you multiply the original rotation with the computed one, to make it rotate by little
8. myObject.transform.localRotation *= tweened;

edit:
And in fact, you could use LookAt
The main trick is to avoid Euler, because it will only fix the Y rotation to something arbitrary

Code (csharp):

1. currentDir = Vector3.Slerp(startDir, Vector3.up, t));
2. myObject.transform.LookAt(myObject.transform.position + currentDir);