math,rotation,quaternions,rotational-matrices,numerical-stability

That Wikipedia article is biased. From http://en.wikipedia.org/wiki/Quaternions_and_spatial_rotation#Advantages_of_quaternions as of Apr 18, 2014: When composing several rotations on a computer, rounding errors necessarily accumulate. A quaternion that’s slightly off still represents a rotation after being normalised: a matrix that’s slightly off may not be orthogonal anymore and is harder to convert...

c#,opengl,quaternions,rotational-matrices,sharpgl

At the end of the day, I want my object (Polygon in SharpGL terms) to rotate about its own axes (or about the "world" axes, but be consistent). I think this answer you put in your question is somehow explaining the situation. In order to perform rotation around object...

opengl,vector,matrix,rotational-matrices

this is called axis angle rotation, the easiest is using the quaternion route: the equivalent quaternion is sin(angle/2)*x, sin(angle/2)*y, sin(angle/2)*z, cos(angle/2) then you use the matrix in the wiki to obtain the rotation matrix ...

javascript,css3,matrix,3d,rotational-matrices

The fix is in this fiddle, my issue was that the browser can't easily do the animations on the individual items. To fix this I simply constructed a cube, and then animated the whole cube, rather than animating the individual faces and it worked. The matrix / vector maths needs...

c++,math,rotation,rotational-matrices,separating-axis-theorem

This should work whether or not polygon origin is aligned to center of gravity. I'll start with the most important stuff, and end with supporting methods that have changed. Edit: Revised implementation. struct Response { Response() : overlap(std::numeric_limits<double>::max()) {} Vector2D axis; double overlap; }; bool FindAxisLeastPenetration(const Polygon& a, const Polygon&...

math,matrix,3d,quaternions,rotational-matrices

vec_res = (inverse(VM) * conversion_to_matrix(q) * VM) * vec_input Is perfectly valid. The problem is... inverse(VM) * conversion_to_matrix(q) * VM is NOT equal to conversion_to_matrix(q) Therefore you have to keep the original equation in its entirety....

javascript,matrix,linear-algebra,rotational-matrices,euler-angles

Can I average the rotational matrices, or the euler angles themselves? Nope. Or am I going to need to convert the data into Quaternions and then apply some kind of averaging function? Yes, only quaternions are appropriate for inter/extrapolation. See 45:05 here (David Sachs, Google Tech Talk). I haven't...

python,numpy,scipy,sparse-matrix,rotational-matrices

If you already have the rotation matrix as a dense array you can simply do m = csr_matrix(dense_rot_matrix) One of the two types csr_matrix or csc_matrix should be used. A better option would be to populate already the sparse matrix which can be easily accomplished using the coo_matrix type, which...

c++,opencv,opengl,rotation,rotational-matrices

I got around this issue with the following procedure: SolvePnP() -> to get rvec and tvec rodrigues() -> rvec to RMatrix transpose RMatrix -> RTMatrix (-RTMatrix * tvec) -> to get TVector create a 4x4 openGL identity matirx -> (I called it GLtransform) GLtransform = glm::translate() -> translate by TVector...

opengl,coordinate-systems,rotational-matrices

The OpenGL modelview matrix works as a stack. Every transformation is performed by post-multiplying the transformation with the current MVM matrix. In other words, it looks like this: New_MVM = Old_MVM * Transformation This causes the transformations to always occur in the local coordinate system. As the article states, you...

android,opengl-es,android-sensors,rotational-matrices,sensormanager

So the rotation vector is definitely the good kind of sensor to use. Both the accelerometer and the gyroscope won't be of any help for what I want to do. However I still have to figure out what to do with the rotation matrices that I have now....

r,pca,rotational-matrices,psych

I'd give manipulate a try - something in the veins of: library(psych) library(manipulate) l <- l_orig <- unclass(loadings(principal(Harman.5, 2, scores=TRUE))) manipulate( { if(rotateRight) l <<- factor.rotate(l, angle, 1, 2) if (rotateLeft) l <<- factor.rotate(l, -1*angle, 1, 2) plot(l, xlim = c(-1, 1), ylim = c(-1, 1), xlab = 1, ylab...

android,opengl-es,linear-algebra,android-sensors,rotational-matrices

You're missing another matrix you must store and transposing the wrong matrix. In addition to the mRotationLock (OM1), when the screen come unlocked you should store the opposite of the current OM2 matrix called OM20T below. You can do this with a transpose. If you had more code I'd show...

computer-vision,camera-calibration,stereo-3d,rotational-matrices,projection-matrix

It depends in which direction R was determined. I.e. is it a transformation of the camera in the global reference frame, or is it a transformation of the points in the local camera's reference frame. The true answer is: Don't worry just check that what you've got is right....