Questions tagged [mesh]
Questions about a network of connected vertices, edges and faces to describe the shape of a specific 3D object.
168
questions
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
1
vote
2
answers
509
views
Rendering 3-D point clouds obtained from depth maps as a 2.5D video
Suppose I have code to generate a bunch of frames, each of which is a depth map(I have access to the matrices which represent depth) which in turn is used to generate a point cloud. One frame would ...
- 11
1
vote
2
answers
2k
views
Very efficient/fast marching cube implementation
I was wondering if there's any known technique/algorithm that would compute a mesh generated by the marching cubes but hierarchically (like a divide and conquer strategy), in the implementation I know ...
- 496
1
vote
1
answer
96
views
Identify plane of symmetry in 3D mesh
Is there an efficient way to identify the plane of symmetry in a 3D mesh? Preferably with existing code / software but if anyone knows how to implement it that would also be helpful.
Example of the ...
- 173
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
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
4
votes
2
answers
502
views
Should you measure mesh complexity in triangles or vertices?
I have seen people using either vertices or triangles as a quick heuristic to estimate mesh memory usage and mesh rendering time.
I always thought vertices were better, because the number of vertices ...
- 1,594
4
votes
1
answer
245
views
Surface fairing, implementation detail
I'm reading through Polygon Mesh Processing, section 4.3 (Surface fairing).
The reference I mentioned defined defines "Surface Fairing" as
The goal of surface fairing is to compute shapes that are ...
- 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
5
votes
2
answers
4k
views
Generate mesh from pointcloud data
Given point-cloud data :
For example.
position + color and normal.
What will you use to generate mesh of this data
and keep reasonable quality for real time cases ?
Additional info to consider:
...
- 51
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
4
votes
1
answer
608
views
Degenerate case of normal computation in marching cubes
I'm implementing the marching cubes, reference is this. I managed to get the geometric reconstruction (the mesh) however I do struggle with the normals.
In section 4 they explain the gradient can be ...
- 496
1
vote
2
answers
419
views
Convert a .X mesh to a modern format
I have a bunch of meshes in the .X format, which isn't supported by many 3D applications today. Therefore, I would like to convert these to a modern format like fbx or gltf/glb.
Since these meshes ...
- 181
0
votes
1
answer
145
views
how to draw mesh equal distance from irregular shape geometry bounding box
I am given an irregular geometry shape with its vertices, bounding box information.
How to draw a smooth mesh equal distance from that irregular geometry shape's bounding box?
Please refer to the ...
- 181
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
9
votes
2
answers
7k
views
How can I convert signed distance field to a mesh?
I can easily make models by Modeling with Distance Functions but I need make mesh from It so I decide to use voxelizing and make triangles for my signed distance field torus like this video.but I ...
6
votes
1
answer
409
views
How to decompose a complex mesh to simple geometry shape programmatically?
I have a complex geometry mesh object, which is an irregular shape.
I want to redraw that complex geometry mesh object using multiple simple primitive shapes.
For example, I want to use cuboid, ...
- 181
2
votes
1
answer
251
views
How to remove internal geometry programmatically in all meshes in .OBJ file?
I have an .OBJ 3D model with many complex meshes shape.
The meshes are complex because each of them have multiple internal mesh located in it.
Meshes with internal geometry is defined as a mesh, ...
- 181
2
votes
1
answer
483
views
Triangulation of vertices of an ellipsoid
I have the parametric model of an ellipsoid like this:
\begin{cases}
x=a_1\,cos \,\eta \:cos\,\omega & -\pi\leq\omega\leq\pi \\𝑦 = 𝑎_2\,cos\,\eta\:sin\,\omega \\ z=a_3\,sin \,\eta & -\frac{...
- 321
0
votes
1
answer
232
views
What is the algorithm used in pbrt-v3 for triangle intersection?
Where's this algorithm come from? Any references?
And a specific question, when the authors compute the transformation from world space to ray-triangle intersection coordinate space, what's the ...
- 293
4
votes
1
answer
966
views
Best way to remesh a quad 3D mesh?
I have a quad-based 3D mesh. I want to:
remesh it while keeping the shape the same
the end output should be in quads
ideally it should have a similar number of verts / polys as the input
ideally the ...
- 173
0
votes
1
answer
247
views
Topology: Polygonal Meshes, Euler's Formula
Firstly, I would like to tell this is my first question on stackexchange and I am a senior school student. Please bear with me, if I am not able to express myself clearly.
I am trying to solve a ...
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
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
1
answer
156
views
How do I replace a mesh's texture with vertex colours?
I have a textured 3D mesh. I want to deduce a 3D mesh without texture, but with an RGB vector color on each node of this 3D mesh. The colors have to be picked from the initial texture. Is there a way ...
- 23
1
vote
3
answers
339
views
Same specular lighting on both tris in a quad (for "low-poly" "flat shading" look)?
Here's an example of the flat shaded squares I want. But my squares are made of two triangles, and I'm getting flat shading of those triangles.
In openGLES 3.1 (android), I'm turning off ...
- 113
3
votes
2
answers
568
views
Fuse detailed road mesh with regular grid terrain mesh
I am experienced with C++ and know more embedded device related stuff but have absolutely no knowledge of computer graphics and its algorithms.
I would like to get a road mesh (based off of a spline) ...
- 31
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
23
votes
5
answers
26k
views
Why are quads used in filmmaking and triangle in gaming?
In film school, in the classes of 3D modeling, I was told that when we model something for films we maintain topology of 4 edged polygons. Any polygon which has more or less than 4 edge/vertex is ...
- 335
3
votes
1
answer
1k
views
Most efficient way to render many OO meshes in OpenGL
I am writing a large 3D game in Java with OpenGL.
Question #1
As of now, I am rendering my 3D objects using a Model class that I defined. This class contains vertex,...
- 163
11
votes
3
answers
928
views
How can I perform a triangle inside test in polygon meshes?
I have 3 vertices (V1, V2, V3) randomly selected on a regular triangle mesh. For these 3 vertices, I have computed the geodesic distance and the path (by using ...
- 233
2
votes
2
answers
2k
views
Extract visible vertices from a 3D geometry model
Let's assume we have a 3D model consisted of XYZ-formatted vertices (such as point cloud model). My problem is given the position and normal of camera or camera ...
- 229
1
vote
1
answer
533
views
Compute area (not surface area) and perimeter of a mesh
I'm currently researching how to compute geometric properties of architectural shapes based on their 3D meshes, and am stuck for some time on the area and perimeter calculations.
First, the area: ...
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 ...
0
votes
0
answers
82
views
3D sphere mesh with a predefined number of vertices and a given adjacency matrix of vertices
I need a 3D triangular sphere mesh with uniformly sampled vertices, say $V$, with a predefined adjacency. Is there a specific way to achieve that?
- 1
4
votes
1
answer
430
views
What is better to use for real-time computing Mesh - Plane intersection points, GPU or CPU?
I want to write plugin (library) for Unity3d (it doesn't matter which framework I will choose for this, question is ), for cutting arbitrary mesh with plane (for simplicity it will be plane for ...
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
4
votes
1
answer
475
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 ...
- 159
4
votes
1
answer
842
views
Calculating Skeleton-Deformed Mesh Normals
I'm implementing mesh skinning in a project of mine. I can calculate vertex positions based on bone transformations, but I've run into a problem with calculating their normals.
From the resources I'...
- 143
3
votes
1
answer
2k
views
Bevel/Chamfer algorithm for arbitrary 3D mesh
I can't find any paper about a bevel/chamfer algorithm for 3D mesh. Bevel has a lot of special cases (corners, different bevel profile, bevel larger than a face). I am looking for robustness.
Do you ...
- 31
7
votes
1
answer
4k
views
Creating a mesh from a point cloud?
I'd like to create a mesh from a point cloud generated by video tracking, ideally using python for some kind of prototype at least.
Initially I thought this is a fairly easy task, connecting the ...
- 596
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
13
votes
2
answers
18k
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 ...
- 233
4
votes
1
answer
213
views
Weird rendering in rectangle mesh shader AKA Why has my basic shader become a modern art generator?
I am trying to translate an old (2013) bit of code from Apple from objective C to Swift with some modifications I need for my simulation.
The code I am translating can be found here
To make ...
- 1,445
0
votes
0
answers
97
views
In a polygonal mesh 3d model which consist of triangles is it possible to separate different objects?
I have a 3d city model that is a collada file which consist of many triangles. When I select the model in a 3d software all buildings are selected. But I want every building to be selectable ...
- 33
4
votes
1
answer
74
views
get partial view points from 3d surface mesh
I have a 3d surface mesh.
Say the camera is located in some points and I want to get the visible points from the 3d surface mesh from the camera view.
I believe this kind of process would be done ...
- 41
4
votes
2
answers
698
views
Combination of Triangles and Quads in a mesh
Is it topological correct to combine triangles with quads to form a mesh. If not, why?
- 43
4
votes
1
answer
499
views
exact down sampling and re-triangulation of mesh data(non-convex)
I have a human body 'surface' mesh data.: triangular mesh (vertices, face)
What I want to get from this is 'exact-down-sampled' version of the current mesh.
Which means.. the processed output mesh ...
- 41
4
votes
2
answers
332
views
Implement own Bend function
I'm trying to write a mesh deformer that bends a Cube around an axis like this:
The bend degree in figure A is 90 and something like 35 in B. So if I know my desired bend degree how can I get alpha?
...
- 57