# Questions tagged [mesh]

Questions about a network of connected vertices, edges and faces to describe the shape of a specific 3D object.

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### 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
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 ...
1 vote
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
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
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
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 ...
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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
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
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
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: ...
1 vote
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
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
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
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
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
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 ...
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 ...
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, ...
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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, ...
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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{...
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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
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 ...
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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
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 ...
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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 ...
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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 ...
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1 vote
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 ...
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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) ...
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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 ...
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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 ...
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,...
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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
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
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
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 ...
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?
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
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 ...
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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
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'...
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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 ...
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
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 ...
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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 ...
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### 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 ...
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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 ...
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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 ...
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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?
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 ...
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