koobas.hobune.stream
Align GameObject to Terrain angle
I'm trying to enhance a simple clamp to terrain script I wrote to also rotate the object based on the angle of the terrain under it. There is probably easier ways to do what I am trying to do, but I'd also like to know why my code is simply not working.
function AlignToTerrainAngle(pos : Vector3, unitSize : float = 1.0) { var frontSide : Vector3 = Vector3(pos.x + unitSize, 0, pos.z); frontSide.y = terrain.SampleHeight(frontSide);
var backSide : Vector3 = Vector3(pos.x - unitSize, 0, pos.z); backSide.y = terrain.SampleHeight(backSide);
var leftSide : Vector3 = Vector3(pos.x, 0, pos.z + unitSize); leftSide.y = terrain.SampleHeight(leftSide);
var rightSide : Vector3 = Vector3(pos.x, 0, pos.z - unitSize); rightSide.y = terrain.SampleHeight(rightSide);
// get pitch angle var pitchAngle : float = Vector3.Angle(frontSide, backSide);
// get yaw angle var yawAngle : float = Vector3.Angle(leftSide, rightSide);
Debug.Log("Pitch angle: " + pitchAngle + " Yaw angle: " + yawAngle);
var newRotation : Quaternion = Quaternion.identity; newRotation += Quaternion.AngleAxis(pitchAngle, Vector3.right); newRotation += Quaternion.AngleAxis(yawAngle, Vector3.forward);
// Rotate the model! transform.rotation = Quaternion.Slerp(transform.rotation, newRotation, Time.deltaTime * 2.0);
}
I feel like I'm pretty close, but the angles are way too small (< 0.3), and assigning the new rotation Quaternion to the transform object seems to do nothing. Even hard coding larger angles resulted in no change.
The Slerp interpolation will only work if this function is called repeatedly (i.e., in Update()), since this variant of using a Lerp function (by giving it Time.deltaTime as interpolation parameter) is more like a "smooth follow", no longer a linear inerpolation. You might also want to increase the 2.0 scaling, to influence the speed at which the new rotaion angle is adapted.
Note that there is a method called Terrain.terrainData.GetInterpolatedNormal(x,y) which gives you the normal at a given position. However, since it is a method of the heightmap data, the values x and y are normalized between 0 and 1, so you would have to compute them by yourself, using your pos.x and pos.z and the actual terrain dimensions+location.
I know this is old, but it may help others as it helped me:
//make platform adjust terrain rotation
var rcHit : RaycastHit;
//Make raycast direction down
var theRay : Vector3 = transform.TransformDirection(Vector3.down);
if (Physics.Raycast(transform.position, theRay, rcHit))
{
//this is for getting distance from object to the ground
var GroundDis = rcHit.distance;
//with this you rotate object to adjust with terrain
transform.rotation = Quaternion.FromToRotation(Vector3.up, rcHit.normal);
//finally, this is for putting object IN the ground
transform.localPosition.y = (transform.localPosition.y - GroundDis)+1;
}
Thank you. Your answer probably causes butterfly effect and save the world from alien invasion.
