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Questions tagged [qhull]

Qhull is a library for C and C++ which implements Quickhull algorithm for computing the convex hull.

Qhull is a library for C and C++ which implements Quickhull algorithm for computing the convex hull.

Homepage: http://www.qhull.org/html

Qhull computes the convex hull, Delaunay triangulation, Voronoi diagram, halfspace intersection about a point, furthest-site Delaunay triangulation, and furthest-site Voronoi diagram. The source code runs in 2-d, 3-d, 4-d, and higher dimensions.

Qhull handles roundoff errors from floating point arithmetic. It computes volumes, surface areas, and approximations to the convex hull.

Qhull does not support triangulation of non-convex surfaces, mesh generation of non-convex objects, medium-sized inputs in 9-D and higher, alpha shapes, weighted Voronoi diagrams, Voronoi volumes, or constrained Delaunay triangulations,

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How to build Qhull into Javascript with Emscripten?

I've been trying to build Qhull for use on the net, and to be honest. I'm completely lost. I've already installed the Emscripten SDK, and I've tried reading through the guides. From what I can gather, it seems that there are two ways to compile a…
ViHdzP
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Constructing convex hull object with known triangular faces

TLDR: I need to construct a python object for fast interior point testing, similar to a SciPy ConvexHull or DelaunayTriangulation. The catch is that I know ahead of time the order in which the triangulation of the points must be constructed: (6…
T Kirk
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How to access extreme points through the qhull c++ interface

I've inherited a piece of code that uses qhull to create the delaunay triangulation of a set of points. For an extension of the code I want to use the extreme points of the triangulation (the points on the 'outside'), but I can't find how to acquire…
Arcturus24
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How do i use Qhull options for LinearNDInterpolator in Python?

I am trying to compute an interpolation with: import scipy.interpolate as si import scipy f = si.LinearNDInterpolator(Q, h) It gives me the following error: QhullError: qhull precision warning: The initial hull is narrow (cosine of min. angle is…
Anon
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pcl::ConcaveHull reconstruct returns a point cloud with all RGB values as black

When I run pcl::concaveHull reconstruct using PointXYZRGB with the RGB values previously defined from scene color values, the returned cloud has RGB values that are zeros or black.
JamesM
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How to remove skinny triangles in scipy.spatial.Delaunay()

I have a scipy.spatial.Delaunay() triangulation, and I would like to remove 'skinny' triangles from it. How would I do this? I have seen that some other software (like here: Houdini triangulate2d) have a 'minimum angle' option precisely to prevent…
ap21
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Contour of scattered data via interpolation or QHull in python

I'm trying to plot a contour at z = .95 out of my data however, I couldn't manage to interpolate as I want. I tried to use griddata as follows from scipy.interpolate import griddata N = 1000 xi = np.linspace(min(x), max(y), N) yi =…
jackaraz
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I'm not able to triangulate a regular point cloud

I easily tessellated two parametric 3D surfaces (both convex surfaces). These are the two tessellated parametric surfaces: Now, my intention is to join both in a single solid. But I'm obtaining this: enter image description here I'm using Qhull…
Alberto Lara
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Error with Qhull. How could I correct it?

Basically, I am using qhull for some simple c++ implementations dhcp-18-189-48-131:qhull-2012.1_2$ cat sample_input.txt 3 # 4 1 0 0 0 1 0 0 0 1 0 0 0 dhcp-18-189-48-131:qhull-2012.1_2$ qhull sample_input.txt QH7036 qhull warning: missing space…
wasabi123
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Can you select the desired number of Voronoi centers in QHull / Matlab

I want to implement a Voronoi k-nearest neighbor solution from "Nearest neighbors in high-dimensional data?" I am currently using MATLAB's voronoin to calculate Voronoi vertices and bins. This function uses Qhull. The problem is that with over 5…
Elpezmuerto
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Qhull(Qhalf) interior point

I am using qhull library for for computing the intersection of half spaces. Although this problem is a dual of convex hull problem, but as its input it needs an interior point of the intersection. As it is stated on their webpage, here, using linear…
Hamed
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Convex Hull calculation in Point Cloud Library fails in 2 as well as 3 dimensions

i'm following the tutorial of the PCL docs for calculating a 2D Convex Hull see here. I have a cloud and some indices, project them on a plane with given coefficients and then calculate the convex hull. Here's the code: PointCloud::Ptr…
moatilliatta
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Difficulty piping with qhull through python

I'm having trouble piping command through QHull in python. I'm currently trying to do so like this: input_command = "rbox c " + str(qpoints) + " | qconvex FQ FV n" command = subprocess.Popen(input_command.split(" "), stdout=subprocess.PIPE) print…
user650261
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Error trying to install matplotlib in Windows

I'm trying to install matplotlib for Python 3.10 in Windows. Im using pip: pip install matplotlib I've already installed NumPy, Cython, Pillow and other libraries needed. But it shows this error: error: Failed to download any of the following:…
Luis Fernández
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How to get all points constituting convex hull,if convex hull is perfect rectangle(python 3)?

open image to see result of below code import numpy as np from scipy.spatial import ConvexHull import matplotlib.pyplot as plt points = np.array([[1,1],[1,2],[1,3],[1,4],[2,1],[2,2],[2,3],[2,4],[3,1],[3,2],[3,3],[3,4],[4,1],[4,2],[4,3],[4,4]]) …
Sanket Chafle
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