Instantiating an object with the correct rotation

Questions & Answers
1

I would like to instantiate an object with the correct rotation but unsure about how I’d do it. If i Instantiate the object on a flat surface it looks fine but if I Instantiate on a vertical or sloped wall, it looks weird. Take the below image as an example:

[54241-capture.png*_|54241]

The slime on the right is flat on the ground but the one on the left is in the same rotation but sticking from the wall. Is there a way I can get the object to like against the wall for a more natural look? This is the code I’m currently using:

#EDIT
I found a post [here][2] that says I should rotate according to the normals of the object which makes sense but I am still having no luck using the following code:

    RaycastHit hit;
    Vector3 dir = -transform.up;
    float length = 0.35f;

    Debug.DrawRay(transform.position, dir * length, Color.green);

    if (Physics.Raycast(transform.position, dir * length, out hit, length))
    {
        SpawnObject(null, manager.slimeBalls, transform.position, Quaternion.LookRotation(hit.normal));
    }

Just for reference, this is the SpawnObject code I am using:

void SpawnObject(Collider col, List<GameObject> objectList, Vector3 position, Quaternion rotation)
    {
        //For each artifact in the list
        for (int i = 0; i < objectList.Count; i++)
        {
            //If a artifact is inactive
            if (!objectList*.activeInHierarchy)*

{
//Set the position to the collision point
objectList*.transform.position = position;*

//Set the rotation to the rotation collision point
objectList*.transform.rotation = rotation;*

//Set the artifact to active
objectList*.SetActive(true);*

//break from the loop
break;
}
}
}
*
*[2]: http://answers.unity3d.com/questions/16952/instantiate-based-on-raycasthitnormal.html*_

2

At the moment, you’re telling your object’s “forward” direction to orient itself facing outward from the surface it’s sitting on.

To get the rotation you’re trying for, you need to add a small, extra step to your process.

Using FromToRotation(), you can adapt your rotation into a small tweak rather than a large change in direction.

Quaternion newDirection = Quaternion.FromToRotation(transform.up, hit.normal);

SpawnObject(null, manager.slimeBalls, transform.position, newDirection);

On this basis, the newDirection would be attained as a relative rotation to the spawner. As an alternative, “Vector3.up” could be used as an alternative to “transform.up” in case the spawner would be rotated.