All Questions
Tagged with polygon computational-geometry
14 questions
1
vote
2
answers
135
views
Given two non-intersecting polygons, how to determine which one is in front
I have two 3D polygons, and in both of them all vertices are coplanar. I set a viewing direction and transform the polygons into the coordinate system of the viewing direction, such that the x, y ...
- 111
3
votes
0
answers
199
views
Generate polygons after marching squares in parallel
I've implemented the marching squares algorithm following Wikipedia's https://en.wikipedia.org/wiki/Marching_squares. The output I got is a set of edges, to which each contouring cell contributes 0, 1,...
- 31
1
vote
0
answers
40
views
How to get a polyline from an image with consistent winding number
I am trying to find an algorithm for the following problem.
Assume we have a black and white image. The image contains a white region that encloses a space. This space may be concave but it has no ...
- 1,831
0
votes
1
answer
131
views
HalfEdge: How to get list of all faces from one face
I need to, starting from one face, iterate over the rest of the faces until I reach the first facet. For this I can use twin, start, end or other info of halfedges, faces, vertex. That is, I need to ...
- 11
2
votes
0
answers
55
views
Divide mesh according to level of detail
Background
I need to remesh by OpenVDB, like what Blender remesh does:
Voxel
Uses an OpenVDB to generate a new manifold mesh from the current geometry while trying to preserve the mesh’s original ...
- 133
0
votes
1
answer
47
views
Differential or intersection of islands of 2D polygons in different layers
I have a 2D layer/section containing the 2D polygons colored in shades of green.
I have another layer containing the 2D polygons colored in shades of blue.
I intend to figure out how different are ...
- 133
0
votes
0
answers
47
views
Cover a polygon with least amount of parallelograms
I am solving the task that is as follows:
Input: a polygon. Can be any kind of polygon without self intersections. Can be a non-convex and with holes inside.
Goal: to cover it with 2 (at least) or ...
- 101
1
vote
1
answer
309
views
Projection of a Polyhedron on xy Plane with CGAL
I am trying to project a Polyhedron on the xy plane with CGAL, which should result in a (2D) polygon.
I wonder, if there is an elegant way to achieve it?
Of course, I can iterate over all surfaces ...
- 21
3
votes
1
answer
951
views
Rounding a corner formed by Arc and Line
Given shapes like these, which contain just Arcs and lines, I want to round all its corners with certain radius. I know the vertices of the lines & arcs these shapes.
I can round the corners of a ...
- 105
4
votes
1
answer
141
views
Vertices of a regular polygon given the incircle radius
How can I find the vertices of a polygon (specifically hexagon) given the radius of the incircle? I want to calculate the vertices of a polygon given the face-to-face distance (inscribed circle ...
- 143
9
votes
1
answer
255
views
How can I check if a polygon can completely contain a circle of a certain radius?
How can I check if a polygon (can also be irregular) can completely contain a circle of a certain radius? I do not want to actually draw a circle inside the polygon but just a boolean outcome whether ...
- 143
6
votes
1
answer
404
views
List of triangles to minimum amount of convex polygons
I'm in search for an algorithm that takes the left side of the following graphic as an input and outputs a minimal amount of convex polygons as seen on the right side of the graphic.
The input mesh ...
- 548
3
votes
2
answers
534
views
An algorithm to find the area of intersection between a convex polygon and a 3D polyhedron?
Suppose I have a set of points in 3D which are all co-planar, and which describe the vertices of a convex polygon. I know the coordinates of all of these vertices, I know the unit normal to the plane ...
- 131
9
votes
1
answer
380
views
Find the longest straight line between two points on surface of polygon
My shape is a slightly concave polygon, and I'd like to know the maximal diameter. I imagine a straight line between two points on the surface of the polygon, such that the line does not pass outside ...
- 191