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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24 views

RandomPoint in a region bounded by JuliaSetPlot

Suppose I use JuliaSetPlot to draw the Julia set of a polynomial. Is there a way, assuming the set is connected, to generate random points inside this region (i.e. ...
3
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1answer
93 views

How to get a clean RegionDifference product

I want to get the difference between the following two regions, an annulus and a crown: Here's the code: ...
4
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1answer
54 views

Region for polygonal frustum?

An example of a frustum of a hexagonal pyramid (a.k.a. hexagonal frustum) from Wikipedia: Is there a quick way to build one, given the Region of two $n$-sided ...
7
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1answer
117 views

MeshRefinementFunction on 2D surfaces embedded in 3D

DiscretizeRegion doesn't seem to run the supplied MeshRefinementFunction when meshing a 2D surface in 3D. For example: ...
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1answer
60 views

Bug in RegionDistance with RegionBoundary?

Code as simple as it is: ...
3
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1answer
142 views

Moment Of Inertia of half cylinder

With cylinder I have: ...
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2answers
130 views

Approximate the piecewise constant with a smooth function

Let us first define a two regions as follow : inner=1;outer=2; reg1 = Disk[{0, 0}, inner]; reg2 = Annulus[{0, 0}, {inner, outer}]; glass=1.5;air=1; Now let's say I ...
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2answers
53 views

RegionPlot3D ColorFunction Not Centered [closed]

RegionPlot (and RegionPlot3D) appears to use the lower right corner of the plot as the origin for the coordinates fed to ...
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1answer
26 views

Computing a Transformation then visualizing with TransformedRegion Function

I have some function $\psi$, I compute the transformation $T = \vec{x} - \nabla \psi$. I'd like to visualize the action of $T$ on a square centered at the origin. The mathematica website shows some ...
6
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3answers
229 views

Exclude a region in 3D plot

I need to exclude a region of $\pi/3\leq x \leq 2 \pi/3 $ and $\pi/3\leq y \leq 2\pi/3$ of this 3D plot: Plot3D[Sin[x*y], {x, -Pi, Pi}, {y, -Pi, Pi}] How to do it?
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1answer
42 views

Failed to compute the area of a polygon or to use a polygon as a region of NMaximize function

I have a polygon generated by some data. Sometimes, I cannot compute the area of some of the generated polygons and I cannot correctly apply function NMaxmize on ...
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2answers
50 views

Exact symbolic area of an intersection of two regular pentagons with parameters

The question of finding the area of intwrsection of two regions with parameters has been answered here using and RegionIntersection with delimeter ...
5
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1answer
171 views

Exact symbolic area of an intersection of two polygons with parameters

On the one hand, can handle expressions which include parameters, including polygons, for example: Area[Polygon[{{1, 2}, {-1, 1}, {2, 5}, {1, a}}]] returns ...
4
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2answers
77 views

Move axis and tick labels in RegionPlot to the top, change border color

I use this code RegionPlot[ Sin[t^(1/3)*y] > 0, {y, 0, 5}, {t, 0, 8}, FrameLabel -> {"y", Rotate["t", 270 Degree]}] and the result is ...
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0answers
84 views

Is this a bug of BoundingRegion of MinBall

...
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1answer
100 views

Circle-based skeletonization demonstration

Skeletonization (or the medial-axis transform) is the process of finding the "middle" axis of a region (expressed as a mask). It is performed by the ...
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2answers
67 views

How to create an ImplicitRegion from a list of 2D coordinates [closed]

I have a set of (x,y) coordinates. How can I link them together to form an ImplicitRegion?
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0answers
33 views

Define BoundaryMeshRegion from matrix of data

Say I have a matrix 'm' with 2 columns and 'r' rows. I want to define a mesh region using each row in the matrix as a point coordinate. Something like the R=BoundaryMeshRegion[{m},Line[1,2,3....,r]] . ...
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2answers
105 views

Drawing a RegionPlot from a Table of Values

I have a 2-D table with numbers 1,2,3,4 and 5 populated in it in a continuous form. From it, I like to create a region plot with five regions separated in this space. Is there any easy way to achieve ...
5
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1answer
40 views

Plotting regions with 1D and 2D components

I am trying to plot a region defined by an inequality which contains both a 2D square and a 1D segment. My issue is that RegionPlot only shows the square and ignores the line. I noticed that if I use ...
2
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2answers
145 views

How can I plot and indicate when the function is positive or negative?

I would like to study the sign of this function (potential) and show the region (positive-negative) These are the parameters followed by the code (left figure) ...
6
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3answers
214 views

Regions for numerically defined Toroidal surfaces

I have data like this: DataVisualizationPlot = ListPointPlot3D[data] And would like to obtain the representing surface like this: ...
4
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1answer
65 views

How to obtain a Region from a numerical (!) function

I'd like to achieve a Region from a purely numerically defined function. Like this one: ...
7
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1answer
198 views

How to deal with Polyhedron as region?

I'm quite new to Mathematica and have big troubles with understanding regions correctly. Especially when using the function Polyhedron I'm completely stuck. According to the documentation, the ...
2
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1answer
108 views

Exporting several Pyramid to a stl file

I made some 3D structure including several Pyramid and tried to export it to stl file. (I have referenced this link : Exporting several prisms (or Polyhedrons) to stl (with filled inner space)) It ...
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0answers
37 views

Implicit region misses definitions

I'm running the code eq1[v_] := eq1[v] = v[[2]] + Tan[\[Pi]/6] v[[1]]; ...
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1answer
68 views

How to improve translating a list of points into a list of 3D volumes

I have a challenging transform I'm trying to accomplish as I try to improve the performance of my 3D GAN. Background: I've been working with data from Berkeley's PEER Ground Motion Database to ...
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1answer
58 views

Obtaining the intersections of 3-D regions using loop?

I am trying to take intersections of several three-dimensional regions by using the regionplot3d command. Currently thinking about how to use looping to take intersections for several 3-D regions. <...
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2answers
69 views

Converting a translated filled curve into a region

How do I convert a translated filled curve into a region? It works without translation: ...
2
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1answer
69 views

How to remove the parallelepiped that encloses the writing or make it invisible?

I have this code that I found somewhere and I love what it does, I've been checking the "line" command to remove the line or make it invisible but I can't get it, and the other part of the ...
2
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1answer
111 views

Create graded mesh

I want to create graded mesh inside a cube, with finer mesh in the left half and a coarser mesh in the right half. My plan was to partition the cube with a 2D plane and then generate boundary mesh ...
7
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3answers
584 views

Solving heat equation on a cylinder with insulated ends and convective boundary conditions

I am trying to solve heat equation on a cylinder whose ends are thermally insulated and its circular face is exposed to convection. Therefore I have Neumann boundary condition on all faces of the ...
3
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1answer
52 views

Export Discretized ImplicitRegion as step using OpenCascade

Following the reply by @user21 to this post on exporting a region to a step file, I tried to do the same for a Discretized ImplicitRegion, but OpenCascadeShape didn't appear to work. Is there a switch ...
12
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4answers
387 views

Finding the largest disk within a convex region using Region primitives

This question asks to find the largest circle within a convex polygon, specifically this one: ...
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1answer
78 views

Intersection between a right elliptical cone region and a plane region

I am encountering difficulties in finding the intersection between a region defined as an elliptical cone and another region. For the time being the other region is a simple ...
12
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4answers
359 views

Pathfinding on 2D regions

How can I find a shortest or near optimal route between two points where the route is constrained within a 2D region? First, consider the following bundle of lines: ...
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0answers
42 views

RegionIntersection not work, only outputs BooleanRegion Object

This is an example to make Pi in 3D dimension Thanks @xzczd for providing the fast version. Link Smoothing the Region? ...
3
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2answers
300 views

Cube cutting problem

Show[Graphics3D[{Cuboid[]}], ContourPlot3D[{x==1/3,y==1/4,z==1/5},{x,-0.2,1.2},{y,-0.2,1.2},{z,-0.2,1.2}]] Three planes divide the unit cube into 8 small cubes, ...
2
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1answer
291 views

How can I make such drawings

This Fig. represents LQU, where LQU is a function of $c_1,c_3$, and $c_3$, $c_i \in[-1,1]$. How can I make such drawings?
7
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1answer
200 views

Smoothing the Region?

There is a 2D Pi I successed transformed it to 3D. ...
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1answer
52 views

Improve performance of evaluating over an implicit region

Consider the following implicit region: ...
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3answers
111 views

Eccentricity of an ellipse

I would like to calculate the eccentricity of the intersection between a cylinder and a plane when I change their relative orientation. ...
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1answer
83 views

How do I properly define and work with region unions?

Suppose I have two regions defined by two hexahedrons (slightly adapted from this question): ...
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1answer
173 views

calculate the flux of a vector field through a surface

How to calculate the flux of a vector field through a surface in mathematica? I've this field: F = (x, x^2 * y, y^2 * z) and this surface: ...
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2answers
153 views

Region and DiracDelta

The following integral evaluates as expected to 1: Integrate[ DiracDelta[x, y], {x, -1, 1}, {y, -Sqrt[1 - x^2], Sqrt[1 - x^2]}] However, if we use a Region, the ...
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1answer
120 views

Checking Membership in Boundary of Conical Hull

I want to check whether a given point is also a member of the edges of a given conical hull. For example, I have: ...
5
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1answer
161 views

Colorize a Region

My searches have lead nowhere on this one. I have a MeshRegion (say, a 2D manifold embedded in 3D) and would like to plot a function on it: such that the color of a ...
1
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1answer
210 views

How to draw this three-dimensional implicit region?

I want to draw the surface of the upper half of the sphere $z = \sqrt {4 x - x^2 - y^2}$ inside the cylinder $(x - 1)^2 + y^2 = 1$ . ...
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0answers
98 views

Analytical Solution to Laplace over Irregular Domain using DSolve

I would like to find an analytical solution to a Laplace equation over the following irregular domain using a mix of Dirichlet and Neumann boundary conditions. I've spent a lot of time trying to use ...

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