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Questions tagged [concave]

Anything related to concave geometric shapes. A geometric shape, by definition, is concave if it is not convex. A shape in an Euclidean space is convex if, given two points A and B, every point of the segment AB belongs to the shape, i.e. AB is a subset of the shape.

Anything related to concave geometric shapes. A geometric shape, by definition, is concave if it is not convex.

In short, a shape in an Euclidean space is convex if, given two points A and B, every point of the segment AB belongs to the shape, i.e. AB is a subset of the shape.

See Wikipedia on:

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How to get the volume of a 3D concave shape?

I am wondering if anyone knows how to get the volume of a 3D concave shape? The Matlab build-in function can only calculate the volume of a convex shape. For example, [K, V] = convhulln(shape.vertices); V is the volume. Here the shape is defined…
Samo Jerom
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find convex an concave corners in a polygon

I am trying to detect if a corner is concave or convex in an arbitrary polygon. I made the function below that computes the angle between all edge-pairs. however one never knows if the if it is the inner or the outer corner angle that it returns. I…
timkado
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Check if an angle defined by 3 points is inner or outer

I've found a problem with the detection of angle types (whether inner or outer wrt the origin of axes), given a set of polylines. I've found dozens of very similar questions, but none of them solved my problem, so I put it here in hope something…
jalone
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Python numpy.diff not giving negative numbers calculating acceleration?

import numpy as np data = [128,64,32,16,8,4,2,1] data = np.array(data, dtype=float) velocity = np.diff(data) acceleration = np.diff(velocity) print(acceleration) The above code gives me the following output: [32. 16. 8. 4. 2. 1.] These…
swaggy pete
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What is the difference between a line segment inside and outside of a concave polygon?

My question is about the creation of visibility graphs in surfaces with multiple convex and concave polygons. My problem is that i am not able to classify whether the line segments connecting the nodes of the same polygon go through or don't go…
Jonas Hasel
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Concave Mesh Triangulation With Known Boundary

I have a set of 3D points that (may) form a concave shape. They are already ordered clockwise. The resulting mesh will be (nearly) planar with some slight height adjustments. What's the best algorithm for me to use in C# (Unity) to triangulate a…
ADaurio
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Render filled complex polygons with large number of vertices with OpenGL

I use OpenGL to render 2D map and in the process I need to render filled polygons with large number of vertices(100,000+). To do this, I tessellated the polygons to triangles using glu tessellator and rendered the triangles with VBO. The polygons…
Shaobo Zi
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Concave Polygon Line Clipping without Degenerate Edges

I have search and researched the internet last days to find a suitable method for my problem. Problem: Clip a concave polygon against an infinite line without direction (Actually a polygon against a plane in 3d but the problem is similar i think).…
Eiken
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Create concave polygon passing through all given points

Given a set of points, I want to create a concave non-intersecting polygon using these points. A convex hull would negate the concave part, while arranging them by x/y coordinates or angles from centre would create spiky artefacts. Is there a simple…
phalanx
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Find a point within a polygon

Is there a way to find a point in a polygon? I don't want to find whether a point is in a polygon but want to find the inside point itself. I tried to use the average of x co-ordinates and the average of y co-ordinates to obtain the centroid of a…
Saiyan
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Is there a way to create a concave physicsBody in SpriteKit?

I have an object on scene and my hero should not go through it, but it should be able to go inside of it, like a boat into the bay, surrounded by the other element. I tried all kinds of physicsBody having it have body with rectangle, texture, with…
Vladimir Despotovic
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How do i check if a cost function is Concave or Convex?

How do i check if this cost function is concave or convex? I also want to find if this has a single or multiple minimums. Effort Made; function [w,pi,costvalue] = main_cost(inputdata, tmax, alpha_ini,somrow,somcol) %main cost function; To…
Young_DataAnalyst
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Whats an easy way to fill a Concave PathGeometry to be Convex (finding the concave vertices & removing them)?

I've got a PathGeometry (polygon) built up of LineSegments on one PathFigure and I'd like to ensure that it's Convex. I have a method using the CrossProduct to determine whether the geometry is Convex, I was assuming that I could just return back a…
softwarequestioneer
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Transform parent element to look concave, also transforming its children respectively

I'm trying to achieve a concave transformation in css to look like these examples (only HUD): (source: pke6.de) I already tried to use skew, however, a skew into 2 directions would be necessary, which does not exist. Another attempt is to split…
Pokeemerald
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MATLAB interpolation wrongly extrapolates over concave boundary

I want to plot my surface solutions from Ansys Fluent in a contourf plot with MATLAB. The solution is a table in ASCII format with scattered points (x,y,z) which describe a plane and a temperature at each of those points. On the first picture you…
Rouven
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