quaternions

Solved I'm making a 3D portal system in my engine (like Portal game). Each of the portals has its own orientation saved in a quaternion. To render the virtual scene in one of the portals I need to calculate the difference between the two quaternions, and the result use to rotate the virtual scene. When creating the first portal on the left wall, and second one on the right wall, the rotation from one to another will take place in only one axis, but for example when the first portal will be created on the floor, and the second one on the right wall, the rotation from one to another could be in

Is there an existing algorithm for converting a quaternion representation of a rotation to an Euler angle representation? The rotation order for the Euler representation is known and can be any of the six permutations (i.e. xyz, xzy, yxz, yzx, zxy, zyx). I've seen algorithms for a fixed rotation order (usually the NASA heading, bank, roll convention) but not for arbitrary rotation order. Furthermore, because there are multiple Euler angle representations of a single orientation, this result is going to be ambiguous. This is acceptable (because the orientation is still valid , it just may not

Transform.Rotate has a very helpful interface for selecting whether or not a rotation should be made relative to world axes or the local axes. Behind the scenes, it's doing some math to the transform's rotation , a Quaternion , with another Quaternion . And the exact nature of this math changes depending on if you choose the local or world flag. How can I do this sort of math without assigning the first Quaternion to a Transform's rotation (wasting memory and/or time) just to do some math with it? Suppose my first Quaternion is Quaternion q1 = Quaternion.Euler(0f,0f,90f); and the second is

I rotated my android device in x direction (from -180 degree to 180 degree), see image below. And I assume only Rotation vector x value is changed. Y and z maybe have some noise, but it should be not much difference among the values. However, I receive this. Kindly see https://docs.google.com/spreadsheets/d/1ZLoSKI8XNjI1v4exaXxsuMtzP0qWTP5Uu4C3YTwnsKo/edit?usp=sharing I suspect my sensor has some problem. Any idea? Thank you very much. Jimmy Your sensor is fine. Well, the rotation vector entries cannot simply be related to the rotation angle around a particular axis. The SensorEvent structure

I have some object in world space, let's say at (0,0,0) and want to rotate it to face (10,10,10). How do i do this using quaternions? This question doesn't quite make sense. You said that you want an object to "face" a specific point, but that doesn't give enough information. First, what does it mean to face that direction? In OpenGL, it means that the -z axis in the local reference frame is aligned with the specified direction in some external reference frame. In order to make this alignment happen, we need to know what direction the relevant axis of the object is currently "facing". However,

I have an object which I want to rotate via keys. The object should yaw, pitch and roll. After trying a lot, I figured out that glRotate has its limitations and it won't be possible to implement something like that with that function. I've researched a bit and found out about quaternion-based rotation. It would be also possible to rotate via a rotation matrix, but almost everyone describes the quaternions as the best ever. I have read about the quaternions and understood them fairly well, but how to implement them in my OpenGL program is still a mystery. Does anyone know a small example? Not