# Align GameObject to Terrain angle

 0 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. more ▼ asked Aug 17 '10 at 07:31 PM Ryan IRL 3 ● 2 ● 2 ● 5 add new comment (comments are locked) 10|3000 characters needed characters left ▼ Viewable by all users

 0 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. more ▼ answered Aug 17 '10 at 09:35 PM Wolfram 9k ● 8 ● 20 ● 52 add new comment (comments are locked) 10|3000 characters needed characters left ▼ Viewable by all users
 0 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; } `````` more ▼ answered Jun 22 '11 at 03:21 PM BLF-Games 123 ● 1 ● 3 ● 12 add new comment (comments are locked) 10|3000 characters needed characters left ▼ Viewable by all users

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asked: Aug 17 '10 at 07:31 PM

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Last Updated: Jun 22 '11 at 03:21 PM