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Questions tagged [regions]

Questions about functionality that defines or operates on regions (i.e., an open, connected set), including geometric, mesh-based, or data and formula-defined regions.

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37 views
1
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1answer
97 views

Unable to compute the measure of a region in four dimensions

I need to be able to calculate an integral with this implicit region: ...
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1answer
66 views

NIntegrate::femrdim: FiniteElement method can only be applied to regions of embedding dimension 1, 2, or 3

As in the title: I'm trying to Nintegrate over an ImplicitRegion, this error appears. No idea what it means. Nothing in the docs. It appears on this line: ...
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1answer
47 views

Make MeshRegion/BoundaryMeshRegion work as a graphics primitive in M11

Mathematica 12 has the nice feature that MeshRegion and BoundaryMeshRegion objects render nicely when included as a primitive in ...
5
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1answer
75 views

Colors for Regions

I would like to make different components of my 3D regions show in different colors (colours). Here are some dimensions for a bolt, washer and plate. I can make the individual components in different ...
4
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1answer
57 views

How to switch off the Mesh on an ellipsoidal RegionPlot3D?

I want to draw 3D ellipsoids, the simplest of which is RegionPlot3D[Ellipsoid[{0, 0, 0}, IdentityMatrix[3]], Mesh -> None] How can I switch off the black mesh?...
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2answers
49 views

Problem defining a polygon

I have two polygons that are very similar as: ...
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0answers
30 views

RegionPlot with FindMaximum

I don't understand why each time I'm launching this computation Mathematica buggs and I get a message from Windows that the Kernel stopped working... I'm trying to get a map of where the value of ...
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0answers
24 views

RegionPlot fails

Consider a function f[x_,y_]:=NIntegrate[g[x,y,z],{z,1.1*x,3000}] where g[x,y,z] is some function. The function f[x,y] is smooth and works perfectly when Plot it....
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2answers
50 views

Finding positive region of continous function

I want to find (and plot) the positive region (within a certain domain say x<3,y<3) of a function ...
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0answers
32 views

How to set integration limits

Consider the functions ...
1
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1answer
71 views

How can I remove a certain point from a 2D region?

I started experimenting with Mathematica a few months ago in college (It's my first year in electronics engineering, so I'm not even close to an advanced user's profile yet). My problem comes when I ...
4
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1answer
68 views

How to make a 2D region on the surface of 3D volume?

I am trying to define an area on a volume that I can use for a boundary condition. This is a minimum working example to show the problem my real problem involves stress analysis. I define a region ...
1
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1answer
64 views

Dashing an area in a region plot where the region is not defined [duplicate]

Can someone tell me how to dash a part of a region where the function doesn´t exist? An example 1 >= x^2 + x > y, where y...
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1answer
48 views

Differing RegionIntersection of Lines vs HalfLines

I seem to get slightly different result when intersecting line segments vs interesting (infinite) lines. ...
2
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2answers
105 views

Fill points into a pre-rotated convex Dodecahedron

I am trying to fill a rotated convex polyhedron with points. This functions well in the unrotated case: ...
3
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2answers
123 views

Visualizing a complicated Region

I was given the problem to find the area bounded by the polar curve $$r=\frac{1}{2}+\frac{3}{2}\cos(\theta)$$ which looks like            &...
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0answers
25 views

RegionDifference not working with one Cuboid and large number of embedded cylinders

I am trying to create a Cuboid with embedded hollow cylindrical regions. It seems to work fine when I use a relatively small number of cylinders (about 20) but does not work when I use a large number ...
0
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1answer
25 views

Comparison between Point And EmptyRegion

My aim is to evaluate the length of a line segment lying inside a sphere. Code ...
1
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1answer
54 views

Plotting a region given by a user defined function [closed]

I'm new to mathematica, so I expect this is just something simple. I've defined the following function: ...
5
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1answer
43 views

How to speed up GeoWithinQ?

GeoWithinQ is a very useful function - is this point within this area? However, it is quite slow. It's not unheard of to have large numbers of points - for instance,...
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3answers
52 views

Checking whether the line is parallel to the plane

I have tried to write a code to check whether a line is parallel to the plane in Mathematica. Using that a plane has the normal vector of $\vec{n}=(a,b,c)$ and a line has a direction vector $\vec{L}=(...
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0answers
29 views

Table with two functions to output matrix with values

So I have a wing modeled as an .STL and I am analyzing its structure so I need its cross sectional area and moment of inertia at points along its span. I do this by moving an infinite plane across the ...
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1answer
38 views

Solve: line and rectangle intersections

I have been trying to find the intersections between a rectangle and a line, following the example given in the Solve function: ...
1
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1answer
60 views

ContourPlot3D in an explicit region

I would like to do a 3D contour plot over an implicit region, however, it seems that mma does not support the arguments within an implicit region for ContourPlot3D, is there any way to get over this? ...
1
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1answer
76 views

Converting .STL from Shell to Solid for stress analysis of wing

I'm new to Mathematica as this is the first class I've had to used it in my undergrad time as an aerospace engineer. Anyway, I have run into a problem that I can't figure out. I have created .STL's of ...
4
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4answers
196 views

How to find image of a complex function with given constraints?

I am very new to Mathematica. I have started learning it only last month. I would like to graph the image of some complex valued polynomials with some provided conditions. For example: $$ p(z_1,z_2,...
1
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1answer
66 views

RegionPlot of annulus gives a mesh

So I tried plotting an annulus in two ways: RegionPlot[Annulus[{0,0},{a,b}]] Graphics[Annulus[{0,0},{a,b}]] Why does RegionPlot give a fractal looking thing? (...
3
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4answers
233 views

How to get regions to plot as graphics?

I want to put an annulus in my graphics object. How can I format a region difference into a graphics primitive? ...
3
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1answer
75 views

Putting a 2D region plot under a 3D plot

I am trying to plot this 3D function over a hexagonal region: ...
3
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1answer
64 views

Finding the complement of a function's domain

I'm trying to find the list of x values not included in my domain of $0$ to $2\pi$. My current code is: ...
2
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1answer
36 views

Discretize Graphics3D with Scale and Rotate?

How can I discretize a Graphics3D object that makes use of Scale and Rotate? When I try <...
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4answers
108 views

How to extract the data points in tabular form from a 3D region plot

I want to solve an inequality e.g. RegionPlot3D[x^2 + y^2 + z^2 > 300, {x, 2, 9}, {y, 3, 10}, {z, 4, 12}] and store x, y, z...
1
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1answer
114 views

Parametric region cannnot be automatically discretized/not a valid region to plot

When I try to plot this simple parametric region: ParametricRegion[{x, Sin[z + t] + Sin[t - z]}, {{x, 0, 1}, {z, 0, 1}, {t, 0, 1}}]; RegionPlot[%] I get errors ...
5
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2answers
146 views

RegionDifference for Cylinder and Cuboid

I wish to use RegionDifference to take a cube shape out of a cylinder. First I make the cylinder and cube and combine them in ...
5
votes
2answers
193 views

Draw bounding region by list of points

Suppose you have a list of data points, either in 2D or 3D; is it possible to plot the minimal bounding region containing all the points? Ignoring holes etc.
0
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1answer
96 views

ImplicitRegion vs DiracDelta [closed]

I've been having troubles with numerical integration over implicit regions, so I checked in a simple example if the result coincides with integrating with a DiracDelta function, and found this rather ...
5
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2answers
134 views

RegionIntersection not returning what I expected

Consider the following implicit region defined on one variable reg = {x > 0 && x < 0} If I Reduce this system, ...
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0answers
26 views

Mathematica crashes with RegionPlot[implicitRegion]

I don't know why Mathematica crashes when plotting this ImplicitRegion (click here for the long expression). Once I define the variable ...
1
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2answers
81 views

Trouble with Calculating Area of Parametric Region

This question stems from an attempt to solve the following question: How to calculate specific area on surface of sphere? First, I parametrize a circular loop: ...
5
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4answers
278 views

Computing surface integral on the unit sphere

I have a function $f$ which takes three unit vectors of $\mathbb R^3$ and returns a number, so $f \colon \mathbb R^3 \times \mathbb R^3 \times \mathbb R^3 \to \mathbb R$ which is defined as $f(\...
5
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1answer
87 views

Construct a section (or slice) through 3D Regions

I would like to draw a section through some 3D regions. I start by making some simple 3D regions as a minimum working example. ...
4
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0answers
40 views

Wrong output of RegionPlot

I think Mathematica goes wrong if asked to plot this very simple region: Region2 = ImplicitRegion[x < -1 && y < -1/x, {{x, -3, 0}, {y, 0, 1}}] by ...
3
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1answer
78 views

RegionUnion for 3D Regions

I make two regions and then find I can't combine them using RegionUnion. Here are the two regions. ...
4
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1answer
116 views
0
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1answer
65 views

FunctionDomain - Meaning of “True” in output and documentation

Can someone tell me the meaning of True in output when I use FunctionDomain please? I guess that the meaning of ...
3
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2answers
89 views

How to plot space of bistable solutions?

I have the following ODE system dx1 = -0.7 x1 y2 dy1 = 0.7 x1 y2 + 1.7 (1-x1-y1) y2 - y1 dx2 = -0.7 x2 y1 dy2 = 0.7 x2 y1 + 1.7 (1-x2-y2) y1 - y2 I have found ...
5
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2answers
734 views

Onion plot of a ball

Consider the following simple example. ...
0
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0answers
18 views

Passing a list of conditions to AND [duplicate]

Say I have a list of some conditions, such as list = {y<x,x<0} And I'd like to plug this into RegionPlot, such as <...
4
votes
2answers
412 views

How would I define a region with multiple holes?

I would like to define a region consisting of a polygon with eight holes in it. This is essentially a stamped piece of metal with eight holes. ...