Questions tagged [mesh]
Questions about a network of connected vertices, edges and faces to describe the shape of a specific 3D object.
177
questions
2
votes
1
answer
652
views
Difference between a spherical camera and a trackball camera
A spherical camera is pretty easy to define.
We have an anchor point C the camera always looks at and a relative position P where the camera is, which can be expressed in spherical coordinates, ...
CommunityBot
- 1
0
votes
1
answer
80
views
Constructing half-edges table from triangle list without hash
Motivation
I am trying to refine a mesh such that each triangle gets subdivided into 4 triangles, but I want the vertices to be shared. For that purpose I need a half-edge data structure so I can ...
CommunityBot
- 1
0
votes
1
answer
146
views
Procedural generation of genus $k$ tori triangle meshes
I am looking for code or pseudo-code for the generation of genus $k$ tori triangle meshes. I want to get something like in the image here. Book/paper references, code, github links, etc. are all ...
1
vote
0
answers
58
views
Piecewise smoothing of a mesh?
Kobbelt et al. published a paper some 20 years ago where they specified how solving Poisson equations on the positions of a mesh lead to removing noise. This can be used for reconstructing mesh ...
- 1,696
0
votes
2
answers
89
views
How to extract region inside a loop on sphere
The input is a sphere(defined by radius and center) and a loop defined by a set of points(unordered, illustrated in cyan in the image above) that satisfy the implicit function of the sphere. How can I ...
CommunityBot
- 1
0
votes
0
answers
35
views
Can STEP files contain polygon data? How do I get a smoother mesh out of a STEP file?
I am trying to work with a .STEP file I have received. Upon opening it in CAD Assistant, I find
its surface as jagged lines, like a low poly model. When I export it as OBJ from there, the edges and ...
- 1
0
votes
1
answer
1k
views
Rotation of meshes in PyTorch
I am doing some project on object reconstruction and I need to rotate an object in PyTorch during the training to make sure I am augmenting the data properly. My data consists of points and it's ...
CommunityBot
- 1
0
votes
0
answers
19
views
How can I understand the logic of Fast Point Feature Histograms (FPFH) descriptor?
I have been using FPFH features quite a lot in global registration and key-point extraction a lot, I also looked pcl page that tries to explain what it is, but fails to give detail to reader in my ...
- 111
1
vote
0
answers
35
views
How to transform face mesh?
We can use ARcore to create custom textures and 3D models for Augmented Faces, like the augmentation of a Fox ears. But aside from augmenting 3D objects, can we "transform" facemesh, for ...
- 11
1
vote
0
answers
44
views
How to find point on mesh at a minimum distance from ray
I'm searching for an efficient data structure and algorithm to compute the minimum distance between a ray and a set of meshes in 3D.
What I expect as a result are the coordinates of the nearest point ...
- 111
0
votes
1
answer
28
views
How to measure distortion of a parametrization?
If you have a map from a mesh into the 2D plane. How do you measure its distortion? I know that theoretically what you do is express the differential map of the transformation then use SVD to figure ...
CommunityBot
- 1
0
votes
0
answers
23
views
Volumetric mesh processing: impact of facet removal on connectedness?
I am working with volumetric meshes - meshes that have vertices (0-cell), edges (1-cell), facets (2-cells) and volumes (3-cells) - and I'm interested in removing facets without breaking connectedness.
...
- 1
0
votes
0
answers
49
views
Floating point precision in 3d modeling software
I'm working on a simple 3d modeling application. I'm using 1 meter as unit of measurement. When working with small triangles where an edge length is around 1 centimeter (0.01 units) or less, I started ...
- 516
1
vote
1
answer
100
views
How to get the accurate number of triangles of an wavefront obj model?
I am confused by a 'wavefront obj' file's true triangle number. For example, I downloaded the Rungholt scene from McGuire's Computer Graphics Archive.
...
- 1,136
1
vote
0
answers
56
views
LOD/culling algorithms with procedural meshes
I am experimenting with procedural meshes. Those are generated at runtime in a compute shader. I'm getting to the point where those geometries are big enough to require some sort of culling/LODing ...
- 161
0
votes
1
answer
55
views
What technique can I use to swap thousands of models per frame?
I need to render a lot of objects that swap their model from frame to frame.
Currently, I am putting every model into a single vertex buffer and giving every vertex an id. I store the same id in the ...
- 991
0
votes
0
answers
22
views
Meshing a set of boundaries?
Say I have a set of closed curves in 3D. I want to connect them together into a 2D manifold mesh.
Something kinda like the drawing, where you are making a triangle mesh that is manifold an connects ...
- 1,696
0
votes
0
answers
55
views
How would you represent a mesh with tris and quads?
My understanding is that, while subdivision algorithms like Catmull-Clark can work for any polygonal mesh (including triangles) it's preferable to start with a quad mesh.
Currently my rendering engine ...
- 215
0
votes
0
answers
42
views
Robust convex hull in 3D?
I implemented gift wrapping in 3D, but I am finding it's just AWFUL at handling anything with coplanarity.
I have spent the entire day trying to fix kinks. Naively I thought that if I detected ...
- 1,696
2
votes
0
answers
51
views
Stitching 2 boundaries together
Let us say we have 2 boundaries of 2 meshes that are roughly aligned, for example 2 generalized cylinders (sweeping surfaces) with a small gap in between. And let us say we want to connect them to ...
- 1,696
4
votes
2
answers
557
views
What is the difference between a "meshlet" and just a small mesh?
Obviously, conceptually, a meshlet is just a small mesh. But what is the reason for making the distinction then? I'm assuming it has to do with how they are implemented.
In a meshlet architecture, ...
- 9,697
2
votes
1
answer
74
views
How to create a mesh from a skeleton?
Say you have a topological skeleton, you want to fabricate a mesh out of it, what algorithms exist to accomplish this?
I know of at least one way, which is to represent each edge as an implicit ...
- 46
1
vote
1
answer
134
views
Best way for rendering Voronoi diagram from Delaunay graph mesh
I have a set of points, which I triangulate to a Delaunay graph to make a mesh.
Every mesh vertex has a unique colour, and I can render it without any problem. But I want Voronoi rendering to be ...
- 9,697
2
votes
1
answer
137
views
Inspecting gltf animation data
I am trying to load gltf data onto an engine I am making and I am noticing that something is wrong with the rotations. I want to be able to see the raw numeric values of the animation data in the gltf ...
- 369
4
votes
1
answer
499
views
Algorithm to map a triangular mesh onto plane preserving angles and distances from one vertex
I have a 3D triangular mesh representing cortical surface of a brain. I also have one vertex of interest. I would like to unfold a neighborhood of this vertex in such a way that both the angles (their ...
CommunityBot
- 1
14
votes
2
answers
21k
views
Programmatically generating vertex normals
I'm working with Kinect face api, it provides an array of vertices and indices for triangles which is to be rendered to make the face image.
The no of vertices and their order in array as well as the ...
- 111
1
vote
0
answers
40
views
Geodesic triangle strip algorithm
I think somewhere in the literature there is an algorithm that, given 2 points on a triangle mesh, finds the triangle strip through which the geodesic passes, but I cannot find it anywhere.
- 1,696
31
votes
2
answers
23k
views
What is the simplest way to compute principal curvature for a mesh triangle?
I have a mesh and in the region around each triangle, I want to compute an estimate of the principal curvature directions. I have never done this sort of thing before and Wikipedia does not help a lot....
- 24.7k
0
votes
1
answer
175
views
Computing vertex normals in mesh triangle soup
I am using c++. I have to find vertex normal in mesh. The mesh is triangle soup. The winding order is inconsistent. I know that it is the sum of all faces normals arround the vertex. But I don't know ...
- 3,030
4
votes
1
answer
1k
views
How to calculate volume of any given 3D mesh
Given 3D mesh with a closed surface. (solid object without hole).
I'm looking for an algorithm to calculate its volume.
There are several ideas, Such as
Voxelized and count voxels
Point cloud and ...
- 411
0
votes
0
answers
34
views
How can we represent a self-intersecting surface without analytic expression in computer?
Suppose we have a suface without self-intersection, then we can store it numerically using grid samples from its signed distance funtion. But what for the self-intersecting case, can we still use the ...
- 11
1
vote
1
answer
268
views
3D head mesh morphing from one mesh into another using coding
I have 2 3D head images and want to morph one into the other (animation) without using blender etc. I want to do it using coding preferably using C++, C# or python(libraries are ok). I have done 2D ...
- 3,030
4
votes
0
answers
447
views
Watertight Mesh Representation
A watertight mesh is one which does not have holes, and for which each face has a designated inside and outside. Such a mesh can be "tetrahedralized", has a defined volume, and can be an ...
- 141
3
votes
1
answer
581
views
Smooth triangular mesh interpolation
I am looking for an algorithm which would smoothly interpolate triangles of a mesh (computed by Delaunay triangulation) where each vertex has some value (elevation in my case). I need it for PDAL ...
- 146
0
votes
1
answer
96
views
Why the Bowyer's version and Watson's version of computing the Delaunay tessellation are equivalent?
Bowyer–Watson algorithm might be the most famous method for computing the Delaunay triangulation of a finite set of points in any number of dimensions. Its Wikipedia page and most textbooks on ...
- 24.7k
0
votes
1
answer
499
views
What's a simple way to find connected components in a mesh?
As stated I have a triangle mesh I want to separate into connected components. One way I would assume would be to do a depth first search on a vertex and remove vertices, then repeat until the set is ...
- 24.7k
0
votes
1
answer
3k
views
Drawing a cube and wireframe opengl
I'm trying to render a cube and it's wireframe together using OpenGL
The main function is this:
...
CommunityBot
- 1
1
vote
0
answers
24
views
Geodesic approximation algorithms for minimal geodesic curvature
Introduction
I am building an application in which given a surface and a pair of points on it, an analytic expression of some geodesic arc (preferably the one with the shortest length), between them ...
- 111
1
vote
0
answers
98
views
Given a mesh, a point on the mesh, a direction and a distance, compute the face+barycentric coordinates of point at that geodesic distance
I am a beginner at graphics. I am given a triangular mesh (assume a manifold mesh). I want to sample a square on a mesh that is independent of the triangulation.
I am following these steps
Sample a ...
- 111
1
vote
1
answer
55
views
Extrude from line and find intersection points
Hey Im currently learning about geometry and vectors and was trying to build a room builder with three js.
I basicly create walls from two points (p1, p2). I draw a line and extrude the line to a ...
- 1,343
2
votes
1
answer
96
views
Does automatic UV unwrapping work with an indexed face set model?
When working with Graphics APIs like OpenGL its common to use an index face set model. That is, multiple faces share adjacent / overlapping vertices by using a list of indices.
Most game engines like ...
- 24.7k
1
vote
1
answer
157
views
What does an algorithm which handles mesh-based image morphing look like?
In recent years, the technology of Live2D has become particularly popular and I have been attempting to find any papers or articles which explain what the mathematics for the mesh-based image morphing ...
- 9,697
0
votes
0
answers
70
views
ray triangle mesh intersection triangles inverted
I'm trying to render a dodecahedron triangle mesh and the triangles seem flipped or mirrored somehow. The first picture is what I should be getting, the second picture is what I'm getting and the last ...
- 1
1
vote
1
answer
91
views
Is There an algorithm to remove intersections between two tetrahedrons?
I have a mesh made up of several tetrahedrons, I know for sure that there are intersections between some of them: how can I remove these intersections, without generating others?
In other terms: if ...
CommunityBot
- 1
0
votes
1
answer
202
views
Are vertices of each LOD version always loaded into VRAM
Are vertices of each LOD version always loaded into VRAM?
I know many game engines have a LOD feature for mesh vertices and textures.
I'm just wondering if all vertices and textures of all(each) LOD ...
- 1,233
4
votes
3
answers
9k
views
How can I get a signed distance (SDF) from a mesh?
I am trying to use constructive solid geometry (CSG) and boolean operators to combine various shapes and get the outer (possibly concave) hull. This seems to work okay when using primitive shapes like ...
- 828
0
votes
0
answers
136
views
Methods to interpolate between 2 topologically identical 3D meshes
I have 2 3D surface meshes. These meshes have vertex-correspondence and have the same topology (same edges and triangles connecting the vertices). However, the vertex positions (3d coordinates) are ...
- 600
1
vote
1
answer
86
views
How to map texture pixels to the corresponding 3D positions?
I have a mesh stored in .obj format with a texture image in .png format. For any "defined" pixel in the texture image, I'd like to compute the corresponding 3D coordinates when the texture ...
- 8,397
2
votes
3
answers
131
views
Looking for a compact file format for outputting 3D geometry with color support
I am looking for a file format to output some 3D geometry. In my case, it only needs to handle very simple shapes - uniformly spaced and sized cubes at points in space. So far I've ended up just ...
- 3,030
0
votes
1
answer
397
views
How to use PCA to reconstruct 3D Mesh？
Given a set of human body mesh {S_i}, for each S_i, the points are N*3, we can do PCA on that. We can use PCA to reduce the dimension of {S_i}, for example to k dimension. Let the main direction of ...
CommunityBot
- 1