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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31 votes
2 answers
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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....
ap_'s user avatar
  • 2,194
27 votes
4 answers
8k views

Why do T-junctions in meshes result in cracks?

I have heard from many sources that having T-junctions in 3D meshes is a bad idea because it could result in cracks during rendering. Can someone explain why that happens, and what one can do to avoid ...
ap_'s user avatar
  • 2,194
23 votes
5 answers
27k 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 ...
Santosh Kumar's user avatar
15 votes
2 answers
13k views

How to Calculate Surface Normals for Generated Geometry

I have a class that generates a 3D shape based on inputs from the calling code. The inputs are things like length, depth, arc, etc. My code generates the geometry perfectly, however I am running into ...
joshwbrick's user avatar
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 ...
Allahjane's user avatar
  • 243
14 votes
2 answers
449 views

Why smoothed meshes in 3D studio end up with the same number of vertices/triangles? How then can they be smoothed with the same geometry?

I am trying to understand why meshes that are smoothed in 3D studio (Modifiers/Smoother) end up having the same amount of vertices/faces before or after that process, as well as the exact same ...
Louis15's user avatar
  • 273
12 votes
1 answer
4k views

What is the benefit of using Half Edge over Winged Edge?

For mesh representation, what is the benefit of using Half Edge over Winged Edge data structure? I understand both mesh representations, the only difference is that half edge uses directional edge ...
Bla...'s user avatar
  • 481
11 votes
3 answers
3k views

Ordering a set of unorganized points along a curve

I have a set of 3D points (which I recover from a library that performs the tessellation of a solid body) that belong to a curve (i.e., an edge of the solid). That means that the curve surely passes ...
andrea.al's user avatar
  • 111
11 votes
3 answers
989 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 ...
mkocabas's user avatar
  • 233
10 votes
1 answer
748 views

Gaussian blurring a function defined over a surface mesh

I have a scalar function defined over the vertices of a surface mesh. I want to compute an approximate (and generalized, I suppose) "Gaussian blur/convolution" of this function over the surface. I ...
Museful's user avatar
  • 205
10 votes
1 answer
601 views

Creating shared vertex normals on GPU

I've mostly succeeded at porting an implementation of Marching Cubes from CPU over to OpenGL compute shaders, but I haven't tackled normals yet and wondering the best way to go about it. My ...
russ's user avatar
  • 2,372
10 votes
1 answer
2k views

Optimal memory access when using lookup tables on GPU?

I'm exploring isosurface algorithms on GPU for a bachelor's project (specifically concentrating on just binary in/out voxel data rather than real-valued fields). So I have a CPU implementation of good ...
russ's user avatar
  • 2,372
10 votes
1 answer
2k views

Pipeline to create Voronoi Meshes

I would like to implement a Maya plugin (this question is independent from Maya) to create 3D Voronoi patterns, Something like I just know that I have to start from point sampling (I implemented the ...
Jiloc's user avatar
  • 201
9 votes
2 answers
8k 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 ...
Seyed Morteza Kamali's user avatar
9 votes
0 answers
485 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 ...
Mugna's user avatar
  • 91
8 votes
1 answer
293 views

Human Readable/Writable 3D Representation Formats/Languages?

My goal is to create 3D meshes without the use of a 3D editor. So I want to know what representation languages and formats there are that are designed for this or otherwise that would be good for ...
Aardbei's user avatar
  • 181
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 ...
p2or's user avatar
  • 596
7 votes
1 answer
365 views

After a deformation operation on polygons, how can I check for and fix inverted polys?

I'm doing a quick and dirty automated deformation routine on a polygon body. If it was a tree, and my axis was in the center of the tree, I would like to bend the body by bending the axis. I would ...
user3531082's user avatar
6 votes
1 answer
101 views

Existing method to automatically fill in this sort of concavity in meshes?

I am working with a PWP3D-like algorithm that renders silhouettes of a mesh in order to segment a frame of video and update an object's pose. Because it is only the silhouettes of the mesh that matter,...
FilmCoder's user avatar
6 votes
1 answer
456 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, ...
user2150279's user avatar
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: ...
barakooda's user avatar
5 votes
1 answer
234 views

Questions about Preconditioning Conjugate Gradient method in Baraff & Witkin 98?

I encountered some problems when implementing the cloth simulation algorithm from Baraff & Witkin 98's Large Steps in Cloth Simulation. Baraff & Witkin 98 Consider the cloth as a particle ...
stanleyerror's user avatar
4 votes
2 answers
805 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?
user55844's user avatar
4 votes
2 answers
562 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 ...
Makogan's user avatar
  • 1,696
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 ...
kitta's user avatar
  • 143
4 votes
2 answers
4k views

How to determine the object-to-world matrix

I want to ray trace a triangular mesh that I load from a file. The vertices' coordinates are expressed in the reference frame associated with the object (i.e the mesh) and I don't know the object-to-...
S.E.K.'s user avatar
  • 141
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 ...
Sirius 5's user avatar
4 votes
2 answers
282 views

Creating a Smooth 3D Mesh from a 2D Outline

I am trying to find (or maybe create) an algorithm for creating a smooth, rounded 3D mesh given a 2D outline. I'm trying to recreate a system from a Gamecube game called Amazing Island, and you can ...
hamulstdubbins's user avatar
4 votes
2 answers
551 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, ...
Chris Gnam's user avatar
4 votes
1 answer
1k 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 ...
ganesha123's user avatar
4 votes
1 answer
540 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 ...
taeyoon's user avatar
  • 41
4 votes
1 answer
162 views

Gradient descent (Not ML) on arbitrary meshes

So I am doing a gradient descent like algorithm on the surface of a mesh and I just noticed something: The above is the geodesic gradient (the distance to a single vertex) Look at where the ear ...
Makogan's user avatar
  • 1,696
4 votes
1 answer
226 views

Saving a mesh and textures into a single file

I'm looking for a format where I could store a triangle mesh and multiple textures into a single file. Most formats only reference an external file for textures. I found that the FBX format should ...
M.K.'s user avatar
  • 163
4 votes
1 answer
261 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 ...
user8469759's user avatar
4 votes
1 answer
458 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 ...
Ivan Yakovlev's user avatar
4 votes
1 answer
925 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'...
lowq's user avatar
  • 143
4 votes
1 answer
216 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 ...
J.Doe's user avatar
  • 1,445
4 votes
1 answer
629 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 ...
user8469759's user avatar
4 votes
2 answers
357 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? ...
lega's user avatar
  • 57
4 votes
1 answer
120 views

Reducing artificial rings in mean curvature of mesh

I have an isosurface/mesh (generated via marching cubes) of a micro-CT scan. Originally the surface looks very noisy, which becomes prevalent when the mean curvature is visualized: To reduce the ...
Steven's user avatar
  • 141
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 ...
Evgenii's user avatar
  • 159
4 votes
1 answer
76 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 ...
taeyoon's user avatar
  • 41
4 votes
0 answers
445 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 ...
Joshua Hyatt's user avatar
4 votes
0 answers
76 views

Distributed Mesh Processing with Hadoop [closed]

Is there a library to do mesh processing (slicing, repairing, etc.) on big models in a distributed way using Hadoop?
user2144's user avatar
3 votes
1 answer
187 views

Why is the valence of regular vertices 6?

So I recently learnt that supposedly for any mesh, and pretty much any scheme, the valence of regular vertices must be 6. It seems to be related to the Euler-Poincare formula but I have not been able ...
Makogan's user avatar
  • 1,696
3 votes
2 answers
172 views

Smart half edge iteration?

In my HE implementation, half edges are stored in an array. When I iterate over the edges, I color all the HE black, and when I do an operation on an edge (e.g edge splitting) I mark both the current ...
Makogan's user avatar
  • 1,696
3 votes
1 answer
578 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 ...
Martin Ždila's user avatar
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,...
clabe45's user avatar
  • 163
3 votes
1 answer
345 views

How to subdivide faces with a half edge DS?

Assume we have a mesh represented as a half edge datastructure. We want to subdivide faces without introducing unnecessary vertices (i.e the new number of vertices must be exactly V + E where V is the ...
Makogan's user avatar
  • 1,696
3 votes
1 answer
345 views

Mesh Simplification Algorithms

I'm currently looking into Mesh Simplification to batch-simplify a large amount of .obj files. It is necessary for these algorithms to preserve the visual representation of a mesh as well as possible. ...
soultice's user avatar