Questions tagged [mesh]
Questions about a network of connected vertices, edges and faces to describe the shape of a specific 3D object.
57
questions with no upvoted or accepted answers
9
votes
0
answers
468
views
3D mesh segmentation simple algorithm
I am developing the algorithm reported in this article:
Least square conformal mapping.
Here is presented an algorithm to flat a 3d mesh on the parametric space, but i don't understand the ...
- 91
3
votes
0
answers
132
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 ...
- 131
3
votes
0
answers
26
views
What expectations should I have of large (> 2 GB) file support in common mesh workflow tools?
I have an experimental workflow that involves very finely subdivided meshes, above the 2 GB limit where signed 32-bit integers stop working, which often causes problems for various tools. I would need ...
- 6,600
3
votes
0
answers
126
views
How can you avoid thin triangles in a parametric shape in a smart way?
I have created a closed 3D mesh using a parametric function. The shape is constructed by taking an arbitrary closed b-spline and scaling it based on one of the parameters (similar idea to a parametric ...
- 1,594
2
votes
0
answers
52
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
2
votes
0
answers
43
views
Wrapping a point cloud skeleton with a mesh
Using Unity I've been producing sculptural forms that look like this. It's made of patterns of cubes that twist around each other. I'm trying to get it into a 3D printable format.
From unity I export ...
- 121
2
votes
1
answer
477
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, ...
- 1,594
2
votes
0
answers
559
views
Recreate geometry from normal map
I have a group of low polygon meshes, with associated normal maps. The normal maps were created by baking from high polygon meshes, which I no longer have access to. Is it possible to recreate ...
- 173
2
votes
0
answers
569
views
HalfEdge data structure in openmesh, create_face function explanation
Does anyone have experience with open-mesh or computational geometry and can kindly explain what exactly happens in the function below?
...
- 496
2
votes
0
answers
117
views
How to model braids?
Many hair simulations render their hair as lines (usually splines). Since hair is a really thin object.
if the hair is braided, rather than having thin infinitesimally small cylinders, you have ...
- 1,594
2
votes
0
answers
147
views
Triangle-based and vertex-based skinning models?
I'm reading the Loper et al. 2015 paper on the Skinned Multi-Person Linear Model and I came across this:
What we would like is a vertex-based model that has the expressive
power of the triangle ...
- 21
2
votes
0
answers
116
views
Algorithm for 3D mesh model segmentation to chart
I'm trying to implement a segmentation model which will divide a 3d mesh model into charts. But I'm having really hard time to find resources in the web. The papers and some other places these ...
- 81
1
vote
0
answers
41
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 ...
- 1,594
1
vote
0
answers
36
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.
- 1,594
1
vote
0
answers
22
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
79
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
0
answers
90
views
Problem calculating tangent space
I am currently writing a 3D rendering engine for educational purposes. In general everything is working except that I am chasing down a problem in my cube mesh / tangent calculations that I can't find....
- 111
1
vote
0
answers
23
views
What algorithms are needed to map displacement to base mesh?
By given belows,
Base mesh(vertices, faces, texture coordinates - UV map),
Normal map(1024x1024 image),
Displacement map(1024x1024 image),
I want to make a mesh which reflects the displacement map. ...
- 11
1
vote
0
answers
189
views
Apply transformation to single vertices in OpenGL in order to deform mesh
I'm making a 2D cell simulation game.
The mesh for my cell is basically just a manually-generated triangle fan that looks like this.
I would like to reproduce the wobbling/vibration effect on the ...
1
vote
0
answers
65
views
Question about simple estimation of the discrete curvature at vertices of a mesh
In this post, Nathan-Reed gave a simple, neat, "heuristic" estimation for the discrete curvature at vertices of a mesh.
In a nutshell, it computes a curvature along each edge incident to the vertex, ...
- 111
1
vote
0
answers
150
views
How to render multiple shaders per mesh
I've tried looking everywhere, but I just don't get it. How is multiple shaders assigned to a mesh if you can only bind a single shader in OpenGL?
Assume I have a mesh with a texture shader and now I ...
1
vote
0
answers
30
views
Boundary Smoothing Algorithms
I have a 2-manifold with boundary, built with marching cubes. Are there any well-known algorithms for smoothing its boundary edges?
Most of the papers I found are concerned with smoothing the surface....
- 111
1
vote
0
answers
139
views
Application of parallel transport in computer graphics and mesh processing
Does anyone know what applications has the computation of a parallel transport on a mesh?
I'm talking about methods such as this one
- 496
1
vote
0
answers
176
views
fastest way to bucket triangles into a grid?
What is the fastest known method for bucketing triangles into an unbounded regular 3D grid?
Specifically, I need an array of buckets. Random queries (which bucket is here) are not necessary, as this ...
- 151
1
vote
0
answers
40
views
Proper design of data structure to store wavefront file information?
Currently I have a naive Mesh data structure to store wavefront files.
This data has 3 buffers for the vertices, normals and UVs. It works well to the point I can render the sponza scene, despite ...
- 1,594
1
vote
0
answers
39
views
How are non-triangular wavefront meshes handled?
I have a wavefront loader, however it only works with triangular meshes.
I have been trying to think how to handle faces with arbitrarily many vertices but I have no idea how they are to be handled ...
- 1,594
1
vote
0
answers
44
views
contract mesh based on mean curvature?
I need to contract(offset) a mesh by a small amount(around 5mm), the mesh itself is quite big (say, 1000mm). The problem is that, I need to contract it based on local mean curvature. That is, for ...
- 41
1
vote
0
answers
307
views
Octahedral mapping for Spherical functions
I guess most of you are familiar with environment maps, they represent distant lighting distribution, and are used to render objects given their BRDF or SVBRDF distribution. Many papers map the ...
- 111
1
vote
0
answers
156
views
How do you get edge flow information from mesh
Below there are two identical meshes, however the first one has edges moving in random directions, the second one has edges moving in a orderly, uniform fashion (edge flow).
i want to be able to ...
1
vote
0
answers
96
views
Advice on synthetic data generation using 3D mesh
I'm developing a deep learning algorithm to find and classify (post consumption) plastic bottles on a conveyor belt. A way to train my model is to get tons of labeled images of each bottle, which for ...
- 11
1
vote
0
answers
50
views
Aligning similar surface meshes consistently
When I have a plaster cast of a mandibula and rest it upside down on a table, in most cases it will be in a stable position.
In real life, I do not have a plaster cast, but a 3D scan, i.e. a surface ...
- 111
0
votes
0
answers
17
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 ...
- 1,594
0
votes
0
answers
28
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 ...
- 95
0
votes
0
answers
31
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 ...
- 1,594
0
votes
0
answers
28
views
What design pattern should be used for undo/redo operations in modeling software
There are multiple ways to implement undo/redo functionality. One is using memento pattern, where you store the state of the object before running each command, and then the undo action means rolling ...
- 506
0
votes
0
answers
28
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
0
votes
0
answers
229
views
Render face AR effects using Mediapipe and ARKit in one app
I am creating app to render AR face effects, like tattoo or make-up or 3D glasses. For Android I would like to use Mediapipe Face Mesh (https://google.github.io/mediapipe/solutions/face_mesh.html) and ...
- 101
0
votes
0
answers
51
views
How images are represented in 3D space?
Many 3D graphics libraries like OpenGL model 3D objects like cube using a set of vertexes and 3D triangles. But I am wondering how images are modelled in 3D space so linear transformations can apply. ...
- 167
0
votes
0
answers
64
views
Explanation for the brute force ray marching method
Hellos, I am new to raymarching and 3D and I use python for my coding. I am trying to make a engine for raymarching and was finding the signed distance function for a mesh. How can I get a signed ...
0
votes
0
answers
66
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
0
votes
0
answers
112
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 ...
- 101
0
votes
0
answers
51
views
Cad ingesting SDK that supports STEP , Parasolid and Solidworks filetypes and Also Meshing
We have an internal CSG (Constructive Solid Geometry) format.Converting/Ingesting other CSG-based files to our internal format is straightforward. We also managed to convert some polygon (mesh) based ...
- 101
0
votes
0
answers
107
views
Is there any open source code available for simplification of tetrahedral mesh?
I am currently working on tetrahedral meshes and I want to downsample the mesh using techniques like Qslim but there is not much about tetrahedral meshes in the literature. I try to use it as a ...
0
votes
0
answers
81
views
How can I render a triangle mesh at 10bit (or 12bit or 16bit) channel depth color?
For a vision research experiment, I have a monitor that supports 10bit/channel (=30bit color). I want to render a triangle mesh in a simple scene that uses the full bit depth, and I want to save this ...
- 1
0
votes
0
answers
44
views
Under what conditions does a mesh operation cause the mesh become non-manifold and how to avoid it?
I'm implementing some mesh operations (e.g. edge collapse, edge split, edge flip etc) and need to ensure applying such operations does not cause the mesh to become non-manifold. However, I'm not sure ...
- 241
0
votes
0
answers
48
views
Calculating minimal voxel size in a mesh
I am developing a script that will determine a minimal voxel size in a mesh. My first thought was to caculate the area of given face. Another approach would be to calculate minimal line length and ...
0
votes
0
answers
50
views
Algorithm to select regions based on curvature on a mesh
I'm trying to understand how to implement an algorithm similar to the one used by Magics' mark surface tool, you can see such behaviour on this video.
Quoting the video: "Basically with this tool ...
user4801
0
votes
0
answers
47
views
MMP Geodesic algorithm I need clarification
I am reading the 1987 paper on Geodesics on polyhedra and I am confused on something.
The paper states:
If $I1==NIL$, the channel is simply that part of $f’$ to the left of $\beta_2c_2$; and if
$I2==...
- 1,594
0
votes
1
answer
808
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 ...
- 111
0
votes
0
answers
99
views
Loop subdivision, certain areas converging towards degenerate geometry
I coded loop subdivision and ran it on a cube with triangle faces. I noticed this:
I am using doubles to represent my vertex positions, I am not 100% sure these are caused by floating point ...
- 1,594