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Questions tagged [4d]

4D involves calculations in four dimensions and typically relates to graphics programming. Use the [4d-database] tag for questions about the 4th Dimension database.

From Wikipedia, as of 5 March 2017‎:

In mathematics, four-dimensional ("4D") is a geometric space with four dimensions. It is typically meant to mean four-dimensional Euclidean space, generalizing the rules of three-dimensional Euclidean space. It has been studied by mathematicians and philosophers or over two centuries, both for its own interest and for the insights it offered mathematicians and related fields.

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How to interpolate and plot a 4-Dimensional hamburger?

I have solved the heat equation in octave via finite difference and produced the following 3-D plot whose point colors correspond to the temperatures in each element of my three dimensional hamburger. My computational resources limit the resolution…
FaceInvader
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Improve surface plot visualisation of scatter points

I want to visualize 4 vectors of scattered data with a surface plot. 3 vectors should be the coordinates. In addition the 4th vector should represent a surface color. My first approach was to plot this data (xk,yk,zk,ck) using scatHand =…
Matthias La
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4 dimensional Hidden Surface Removal

I'm trying to program a little 4d game. I use C++ and OpenGL. This website brings a good explanation on how to enhance 4d images: http://eusebeia.dyndns.org/4d/vis/07-hsr.html#Enhancing_4D_Projection_Images they tell to apply a 4d Hidden Surface…
Pella86
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How do I construct a piecewise polynomial (cubic spline) for 4D data in MATLAB?

I have a problem in which I have to interpolate 4D data d = f(a, b, c) often, because the interpolation happens within an optimisation routine. Now, at first I programmed this using Matlab's interpn function. However, the program obviously became…
Sam
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How to add the indices (x,y) of array elements (u,v) to get an array of elements (x,y,u,v)?

I wrote a function that adds the indices of each element in the array to the elements. Examples: First element is [10,11], index is [0,0] -> Becomes [0,0,10,11] Second element is [12,13], index is [1,0] -> Becomes [1,0,12,13] How can I optimize…
Honey Gourami
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interpolate v from irregular x,y,z points in R

I am trying to use R to interpolate a response value v from irregularly placed 3-dimensional treatments x, y, z. In this case, I have 50 unique 3-dimensional points (treatments in my experiment), and one response variable. I have one value of v for…
Jake L
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connecting points in n-dimensional hyper cube

I am experimenting with creating 3d like sketches in processing without using the p3d renderer. I have managed to make a cube but for it I hardcoded all the coordinates and connections and once you want to add another dimension it begins to get a…
Benedikt Vilji Magnússon
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Making a 4D plot in R with different x, y, z colors and lengths

I have a 30 x 16 x 9 matrix that I would like to visualize via a 4-D plot in R. I have tried scatter3D() in packages plot3d and scatterplot3d. x <- seq(10, 300, 10) y <- seq(5.0, 20.0, 1.0) z <- c(seq(0.5, 4, 0.5), 10) …
harmony
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How to plot contour lines on a surface plot? (4D)

I would like to make a 4d plot, where you have X, Y, Z (as a surface) and C (displayed as contours on that surface). What I have right now: What I would like to have: I suspect the answer will be some trick with facecolors or countourf3d but I…
leermeester
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convert 4D .nii file to .png

I have a 4D .nii file like "filtered_func_data.nii" from: [https://nifti.nimh.nih.gov/nifti-1/data] By loading the data and access the img field: S = load_nii('filtered_func_data.nii') S = hdr: [1x1 struct] filetype: 2 fileprefix:…
user1603454
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Gnuplot: How to plot heat maps on three coordinate facets to visualize 4D data

I am new to Gnuplot and unfortunately have to start with a (for me) nontrivial problem. I have X-Y-Z-Temperature data. So I have for every spatial coordinate a temperature value. This comes somewhat…
Toby
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Changing Facecolors in four dimensional matplotlib surface

I'd like to draw a matplotlib surface plot with 4 dimensions. Originally, I would have the data in: [(X, Y, Z, P)] So I'd like to have a 3D Surface, but with a colormap, that is represented by the values of P. I saw an quite good solution for my…
R. Steigmeier
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4D matrix operations in Matlab

I have a set of 4D matrices in Matlab. The first three dimensions are spatial, the last is temporal. That means each voxel is a time series. If Img is the 4D image, Img(x,y,z,:) is the time series of voxel with coordinate (x,y,z). Now I want to…
machinery
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Simplifying a four-dimensional rule table in Matlab: addressing rows and columns of each dimension

I'm currently trying to automatically generate a set of fuzzy rules for a set of observations which contain four values for each observation, where each observation will correspond to a state (a good example is with Fisher's Iris Data). In Matlab I…
Cate
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How to plot 4D contour lines (XYZ-V) in MATLAB?

I have dataset of XYZ as the coordinates and V as the value at each point (100x4 matrix). I plot the 3D surface using patch. (by faces & vertices) How can I plot the contour lines of V (NOT Z) over the 3D surface !? ( The Contour3 function plots 3D…
Omid1989
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