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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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Given a large set of vertices in a non-convex polygon, how can i find the edges?

I have a set of vertices(called A) and I want to find all the border vertices such that this border vertices set is an outline of the shape. Many of the vertices in A are redundant because they are inside the shape, I want to get rid of these…
tommy chheng
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Scaling an arbitrary polygon

I've been scouring the internet for days, but have been unable to find a good answer (or at least one that made sense to me) to what seems like it should be a common question. How does one scale an arbitrary polygon? In particular, concave…
Craig
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opencv find concave hull

I have a set of discrete points shown in an image, like the following I want to reconstruct or up sampling (I'm not sure what's the correct way to describe it) the image, so that the result image would be like the following. It doesn't need to be…
user1964417
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How do I cut triangles out of a concave Delaunay triangulation?

I'm using Delaunay to triangulate a concave polygon, but it fills in the concavities. How do I automatically remove the triangles that are outside the polygon boundaries?
Archagon
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Drawing a concave polygon in OpenGL

I have a concave polygon I need to draw in OpenGL. The polygon is defined as a list of points which form its exterior ring, and a list of lists-of-points that define its interior rings (exclusion zones). I can already deal with the exclusion zones,…
Daniel
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How to form a Concave shape out of Convex shapes?

i'm trying to get around the rule of only being able to form convex shapes in the SFML c++ library. To do this I'm planning on testing given vertices, and if concave, splitting the vertices into groups, testing each groups' concaveness, and…
Griffin
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Concave collision detection in Bullet

I am a Bullet rookie, so I apologise in advance if my questions sound trivial to you. I need to load a set of concave triangle meshes from .stl files and perform collision detection. Objects can be moved by the user. From the user manual, I read:…
Nic
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Is there an efficient\easy way to draw a concave polygon in Direct3d

I'm trying to draw a polygon using c# and directx All I get is an ordered list of points from a file and I need to draw the flat polygon in a 3d world. I can load the points and draw a convex shape using a trianglefan and drawuserprimitives. This…
NotJarvis
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Libgdx polygon triangulation

Ok, so I have a polygon (simple but concave) that I'm trying to cut into triangles to make it collide with an other polygon. I knew my polygone was concave, so i decided to use LibGDX EarClippingTriangulator to manage to cut it into triangles. So,…
Sebastien Servouze
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Concave polygon drawing

For drawing complex concave polygons with OpenGL, is it better to tesselate it into triangles, or use the stencil buffer? I'm guessing the stencil buffer would be faster for a single frame, but triangulation would be better for multiple frames if…
Zifre
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How to 'fill in' deep concave regions of 3D shape in Python

I have data describing the volume contained within 3D cell wall structures, both voxel data (1 inside cell wall, 0 outside cell wall) and surface meshes (3D coordinates and associated triangulations). What I'm after is simply the global outline of…
harry
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concave polygon into convex polygons using r

I am trying to split a concave polygon into convex polygons using r. I am trying to figure out how to successfully accomplish this for one polygon with the hopes of implementing this on a large number of polygons in an automated way. The only way…
sea83
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Detecting multiple polygon intersections (java)

Background: This project involves mapping regions in GIS environment. I need to find then the intersection of one set of polygons with another set of polygons. I achieved this by casting my map-compatible polygons as Polygon2d…
wjgood
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3D contour of a list of points (concave hull)

I have a list of Vector3 points in c#, and I need to calculate the concave contour of these. There's really a lot of references around, especially for -convex- resolution (which I have successfully implemented already, thanks to graham's…
roamcel
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How to create a Concave view on edit text android

I am trying to achieve the view present in the below picture I tried all possible solution that I found but didn't worked for me My tried code
Pritish Joshi
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