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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How to slim nose using face mesh [closed]
I want to implement the nose slimming beauty effect programmatically. I was seeing the YouCam app, and they do it in a perfect way. How can we achieve that in code? Are there any techniques or free ...
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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 ...
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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 ...
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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 ...
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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 ...
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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.
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48
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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 ...
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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.
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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, ...
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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 ...
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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 ...
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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 ...
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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.
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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 ...
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164
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Catmull–Clark issue with plane corners
I implemented catmul clark based on this Wikipedia article.
And it seems to work fine for meshes where the edge point count is equal to the face point count, but not for planes where the corners have ...
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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 ...
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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 ...
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Computing heat diffusion creates weird results
I am trying to model heat diffusion on the surface of a mesh. I annexed the most important bits of theory about this topic as screenshots on the question see the bottom.
The crux of the issue is we ...
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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 ...
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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,...
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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 ...
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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 ...
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Differential or intersection of islands of 2D polygons in different layers
I have a 2D layer/section containing the 2D polygons colored in shades of green.
I have another layer containing the 2D polygons colored in shades of blue.
I intend to figure out how different are ...
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Render Duplicate Miniature Scene Replica
Context
I am working on project for implementing and user test a World-in-Miniature (WIM) interface for VR. A WIM essentially is a replica of the scene the user is currently in, but in miniature.
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Silhouette below 3D model
There are some 3D applications which can cast shadow or silhouette below 3D models. They render pretty fast and smooth. I wonder what kind of technology is the standard procedure to get 3D model ...
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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 ...
