# Tag Info

Accepted

### How to speed up RotationMatrix?

Having this problem so often, I also generated some tools to handle it which I'd like to share. This is the code (along with a usage message which is basically a small modification of ...

### How to roll a graph on the y-axis

We calculate the tangent vector of parametric curve {t^2,t} and the ArcLength from 0 to <...
• 79.7k
Accepted

### How to animate an impossible image

Edit To get the original picture orientation,we can add π to θ. ...
• 79.7k

### How to roll a graph on the y-axis

Assuming you mean roll as in the way a circle rolls across the floor, you need a unit speed arc-length parameterization of the curve $(t^2,t)$. Why? Becuase the key behavior of rolling is no ...
• 3,986

### Generating Mesh of Rotated Graphics

As an alternative you can use BoundaryElementMeshRotate (and a few other Boolean operations) for boundary element meshes that are part of the FEMAddOns paclet. The ...
• 40.4k

### Converting a rotation matrix to a quaternion

I needed to do this recently, so I broke down and decided to write routines for interconverting quaternions and rotation matrices. I'll give the quaternion to rotation matrix routine first, since it'...
Accepted

### Solving for Euler Angles

As noted, you can use FindGeometricTransform[] in tandem with EulerAngles[]: ...

### Generating Mesh of Rotated Graphics

I think the failure to discretize your first Graphics object is a bug. But, instead of creating graphics objects and then converting them to ...
• 131k

### How to rotate 3D ellipsoid with built-in functions?

TransformedRegion[] can quickly determine the rotated ellipsoid: ...

### How to speed up RotationMatrix?

I have previously used the following routine based on ideas by Möller and Hughes in these previous answers, but it would be good to have it as an explicit answer here: ...
Accepted

### Multiply vectors in a matrix by a matrix

You can actually use Dot directly. It works in unintuitive ways with tensors. ...
• 1,531

### Why the rotation degree of flow field is different from the angle specified by RotationMatrix function

That is not a problem with Mathematica. Rather a fundamental one in your approach: you're not transforming points, but rather vectors: You need to rotate the input, and then also the output, because ...
• 3,501
Accepted

### How can I make an animation when using RevolutionPlot3D?

Edit animate axis is the rotation axis, we can set axis={0,0,1} or axis={1,0,0} etc. ...
• 79.7k
Accepted

### How to rotate a triangle to get this picture?

A starting point. ...
• 79.7k
Accepted

### Rotating Vectors in space

I think you want a single transformation function for all points, rather than one for each point independently as kglr's answer currently shows. ...
Accepted

...
• 399k
Accepted

### The inverse problem of rotation of stress matrix

So the problem is as follows: Given two symmetric matrices A and B, find a rotation R that ...

### Maintaining shape size while rotating in GraphicsGrid

Translate a circle to the same location. Set the color of the circle to White and you will have what you are looking for. I am sure there are more formal solutions ...
• 56.2k
Accepted

### Reverse the rotation of an animated gif and create a mirror image of it

To keep same speed for GIF import its "DisplayDurations": dur = Import["/Users/Vitaliy/Desktop/wheel.gif", "DisplayDurations"] And ...
• 73.5k

### Axis/Angle from rotation matrix

Here is a slightly shorter re-implementation of Jens's method, which uses the "Pixar method" (itself a modification of Frisvad's method) to generate an orthogonal basis: ...

### Manipulate - performance during 3D rotation

This answers the slowness part. It is slow because you are using exact numbers for degrees and the matrix was not packed then. Compare the timing: Before: After Just change this one line: ...
• 149k

### Finding optimal rotation matrix

RotationMatrix ...
• 37k
Accepted

### What is the meaning of this code section?

This code defines a function, #4 Boole[Norm[({x, y} - #1).RotationMatrix[#3]/#2]^2 < 1] & applies it to each element of ...
• 62k
Accepted

### Vectors do not define a plane when constructing a RotationMatrix

Edit Another way is use perturbation. u = {0, 1, 0}; v = {0, -1, 0}; m = Limit[RotationMatrix[{u, v + t*RandomInteger[20, 3]}], t -> 0] ...
• 79.7k
Accepted

### Maintaining shape size while rotating in GraphicsGrid

The different sizes are created by the unnecessary "GraphicsGrid" that scales the different pictures. Without it: ...
• 54.6k

### Maintaining shape size while rotating in GraphicsGrid

Specify ImageSize in each Graphics using the (still undocumented) syntax ...
• 399k
Accepted

### How can I rotate a cube uniformly?

By choosing three uniformly distributed angles for generating the rotation matrix you do not end up with a uniformly distributed rotation matrix. See also this link. You need to choose non-uniformly ...
• 629
Accepted

### How to make a ParametricPlot3D curve rotate smoothly?

The use of Dynamic below keeps the ParametricPlot from reevaluating, which leads to smooth behavior: ...
• 241k

### Rotation of area

Method-1 We integrate the circles whose center is on the line y=1 and radius is the distant from the point to the line ...
• 79.7k