I'm trying to rotate a piece by special conditional increments (ie. 30, then 90, then 150, then 180, then 210, then 270, then 360) on an arbitrary axis in global space. Sounds easy enough, by checking which of these your axis is at and then setting it to the next one. However, in global space, a rotation in one axis will often be translated as changes to the others to keep it showing the way you meant with Unity's Z,X,Y rotation application order. To see an example, try rotating something to 180 degrees in the Y axis, then try doing the same with the X axis to see how it only ever gets 90 degrees away from 0 before changing other axes and coming back down.
There doesn't seem to be a difference between Transform.localEulerAngles and Transform.eulerAngles, both of which return the local ones. Thus, given all the possibilities for how a given global rotation can be represented in the local axis coordinates, is there a way to measure its "global rotation" of only one axis sanely?
Other than comparing it with objects that have known rotations, probably not. Using euler angles for this isn't a good idea, because the rotation itself isn't actually stored that way- the euler angles are calculated from the Quaternion.
If I take the time to learn how quaternions work, will the global angle be easily readable directly, so I don't have to store them in a separate Vector3 as mentioned below?
Answer by simubrett
Mar 13, 2012 at 01:43 PM
Well, if you want a rotation about an arbitrary axis, you won't be able to check a single component against a value. Just make another property on the GameObject that stores the object's "current angle" (the 30, 90, 150, ... above) around your arbitrary axis, and have a way to get the "next angle" around that axis given whatever your current angle is. Then just use transform.RotateAround to rotate your object sensibly.
For instance, when you're going from 30 degrees to 90 degrees:
float CurrentAngle = 30.0f;
float NextAngle = 90.0f;
Vector3 axis = new Vector3(whatever);
transform.RotateAround(transform.position, axis, NextAngle - CurrentAngle);
Thanks. I considered doing that but wanted to make sure I wasn't being wasteful if there was an easier way to calculate a global angle from local Euler angles or directly from the Quaternion. I may end up having to store it statically like that though.
Up to 2 attachments (including images) can be used with a maximum of 524.3 kB each and 1.0 MB total.
The best place to ask and answer questions about development with Unity.
To help users post good questions and use the site effectively we have posted a user guide.
If you are a new user, check out our FAQ for more information.
If you are a moderator, see our Moderator Guidelines page.
We are making improvements to UA, see the list of changes.
For troubleshooting common problems with Unity 5.x Editor (including Win 10).
Answers and Comments
6 People are following this question.
Matching 2 axes rotation only of 2 gameobjects
problem rotating an object c sharp
Add a Vector3 to the rotation of an obj and have it behave with logic!
rotation with eulerangles and raycasting.
object placement on sphere, rotation deform