Questions tagged [geometric-transform]

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95
votes
4answers
12k views

How to peel the labels from marmalade jars using Mathematica?

How can I detect and peel the label from the jar below (POV, cylinder radius, jar contents are all unknown) to get something like this, which is the original label before it was stuck on the jar?
33
votes
3answers
2k views

Movable text on a curve

Having an arbitrary curve defined as InterpolatingFunction, what is the best way to place a text on this curve? The text generally has two rows, for example: ...
10
votes
2answers
351 views

Why doesn't Normal[] work on GeometricTransformation?

I have a polygon on which I'm applying a GeometricTransform and I want to get the coordinates of the transformed polygon. ...
20
votes
5answers
9k views

How to draw a great circle on a sphere?

I apologize for the text description, but new users are not allowed to post images. I want to draw a circle that cuts through the center of a sphere and has an inclination of 15 degrees with the ...
8
votes
1answer
362 views

Unexpected behavior of GeometricTransformation

Bug introduced in 8.0 or earlier and persisting through 11.2.0 or later I have the following mapping on the complex plane: $$ z \mapsto \tau \mu z-1, $$ where $\mu$ is complex, $\tau$ is real number....
5
votes
2answers
383 views

Removing anomalous points from data

I have two sets of 2d-data points which can be transformed in each other by using a certain transformation function. The problem is that in both data sets there are points which do not have ...
12
votes
2answers
994 views

Applying non-Affine transforms to 2D polygons with textures

I am trying to create a vanishing point perspective transformation of 2D polygons, for example transforming the red polygon into the blue polygon: ...
6
votes
1answer
279 views

Plot points shifted (a lot) in output and PNG export but not in PDF export

Bug introduced in 8 or earlier and fixed in 12.0.0 Consider the following code: ...
19
votes
1answer
3k views

How to map an image to get an illusion of 3D

I would like to distort or map a given JPEG so that it looks 3D when viewed from certain angle, as in this YouTube video. The most interesting part of the video: I usually use conformal mapping (a ...
13
votes
2answers
4k views

Application of the projection matrix: Removing perspective distortion

I know that there are many posts about image treatment, but I still have trouble with this little challegene. Baisically I want to remove the perspective distorsion form this image: (source: http://...
9
votes
2answers
1k views

How to get UV mapping of 3D tube

Here is cylinder data: file We can mesh the surface, thanks to lalmei, Belisarius and Simon (link) How to achieve uv mapping from a 3d straight and curved tube? Working code: ...
11
votes
6answers
529 views

Make a series of points curl

Say I have a series of points that make a straight line... (Fig 1) points = {{0, 0, 0}, {1, 0, 0}, {2, 0, 0}, {3, 0, 0}, {4, 0, 0}, {5, 0, 0}} I can rotate these ...
4
votes
1answer
1k views

Rotating a contour plot

I am working with some students on transforming conic sections by rotation of axes. I would like to create a simple Manipulate where I plot the before and after ...
16
votes
3answers
403 views

Weird behaviour when using Scale, Rotate in Graphics

Bug introduced in 8.0.4 or earlier and persisting through 11.2.0 or later (Edited to simplify drawing) I have a drawing of two tangent circles: ...
13
votes
2answers
249 views

Why BoundingRegion does not work well?

Bug introduced in 8 or earlier and fixed in 12.0.0 The underlying bug is unstable and wrong rendering of Disk[] and Circle[] ...
10
votes
1answer
139 views

What does the alignment error returned from FindGeometricTransform measure?

FindGeometricTransform returns "the alignment error together with the transformation function." How is the alignment error computed? I ask because if you iterate <...
5
votes
1answer
500 views

How to transform general Ellipsoid into rotated axis-oriented one?

Recently, I discovered a long-standing bug in the rendering of Disk and Circle primitives after applying ...
13
votes
1answer
642 views

How to align a poster?

I'd like to crop and transform out the magazine cover so that it is rectangular. I read the docs for ImagePerspectiveTransformation, and here's where I got to. ...
14
votes
3answers
1k views

Rotate a grid, made up of lines, so that it aligns with the xy axes

While working on an answer for another problem I hit upon one of my own. I took the image given in that question and cleaned it up so that I could detect the grid lines: ...
13
votes
2answers
534 views

Extracting data from analog screen photograph

I'm using an analog profilometer from the 1970s and need a way to digitize the data and the only way is through a photograph. I've searched but all I could find was how to extract data from computer ...
13
votes
3answers
1k views

Coordinate system transformation problem (about Euler angle)

This question comes from the work that constructing the general cylinder by the NURBS. I have implemented the point-set $P_1,P_2,\cdots,P_n$ that in the $O-xyz$ plane, now I want to implement the ...
7
votes
3answers
991 views

Identifying when two graphic objects overlap

I'm designing a small demonstration that helps to visualize the reason behind shaping an electrode that is used to probe a surface: ...
4
votes
3answers
1k views

Drawing the Pursuit curves

I was reading this post on Filling Space with Pursuit Polygons. I didn't really see where the filling was, but found it quite interesting. Then I saw these pursuit ...
13
votes
1answer
909 views

Compose many Geometric Transformations for 3D Graphics

I'm struggling to understand what would be a good way to compose several geometrical transformations to create a single TransformationFunction to be applied to a <...
3
votes
1answer
147 views

How to extrude a tapered shape (starting from a previous answer)

I have a shape given by ...
2
votes
0answers
62 views

How to get explicit result of geometric transformation? [duplicate]

Seems like this simply rectangle rescale should work and return the exact coordinates of the transformed resulting rectangle (which should be ...
6
votes
3answers
411 views

Affine transformation of circular arc in 3D

Start with a quarter-circle of radius 1 centered at the origin and lying in the $xz$-plane: arc = ParametricPlot3D[{Cos[t], 0, Sin[t]}, {t, 0, π/2}] I want to ...
3
votes
1answer
374 views

Projecting a Graphics3D object onto a plane

I would like to project a 3-dimensional cone onto a plane and mark the intersection (which is an ellipse) with a line. I find cone2 by performing a transformation ...
2
votes
1answer
92 views

Difficulty Displaying an Untransformed and Transformed Graphics3D Object with Show

Update: This bug has been fixed The bug has been fixed and the code below is working in $Version=12.1.1 for Microsoft Windows (64-bit) (June 19, 2020). Original ...
2
votes
1answer
71 views

How is the error of FindGeometricTransform calculated? [duplicate]

This question has beeen asked here but was not answered. How is the returned error calculated? I cannot find any information about this in the documentation of ...
2
votes
1answer
702 views

Plotting in projective space

I am having difficulty figuring out how to plot to projective space. Suppose I have a region which I have plotted such as: ...
1
vote
1answer
590 views

Custom TransformationFunction in Graphics? GeometricTransformation::nonaffine error

There are many functions in Mathematica, which return expressions with TransformationFunction head, for example RotationTransform. Unfortunately, there is no ...
0
votes
1answer
80 views

Need help understanding Graphics Translate

I created a star pattern that I was trying to apply to a circle of pentagons, but the Translate had a slight offset, and I don't understand why. When I drew the ...