Questions tagged [3d]
Questions and problems dealing with three-dimensional space, including 3D meshes and other data structures, vector math, transformations, etc.
244
questions
1
vote
1answer
29 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 ...
0
votes
0answers
17 views
Quadric Edge Collapse Decimation of an object for reducing number of its vertices damages the original shape of object
I have been using "Simplification: Quadric Edge Collapse Decimation" for simplifying my meshes to only have ~800 vertices and it has been working with a couple of meshes I tried.
However, ...
1
vote
0answers
8 views
How to extrude a face from a selected mesh in Babylon,js using the ExtrudeShape method?
I'm trying to extrude a face from a selected mesh in Babylon.js using the ExtrudeShape but can't figure out why I got flipped faces.
The bottom extrusions always comes flipped for a reason I ignore.
...
0
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0answers
38 views
UV coordinates calculation broken
I've tried using the classic formula of calculating barycentric coordinates.
When the plane on which you are projecting the texture is collinear to any of the base vectors it crashes with a division ...
0
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0answers
18 views
How to draw a pdb 3d structure in webgl?
I am trying to create a 3d structure in webgl using 3d coordinates from a pdb file mentioned below: https://www.rcsb.org/structure/1RE2
I don't know which one is the appropriate one, so i used gl....
0
votes
0answers
14 views
Translate the camera with Pan gesture (when it is rotated )
I am new here
I am not good in math
SO what I need is I need to translate the 3D camera with Pan gesture on 2d Screen
With below code it is working
But if camera has some Euler Angle (rotated ) then I ...
1
vote
2answers
72 views
0
votes
0answers
38 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 ...
0
votes
1answer
14 views
Plotting points along a 3D line segment
I'm trying to plot some points along a 3D line segment and could really use some help. In 2D, I've found success getting the angle of the line, the sine & cosine of the angle, and then adding the ...
0
votes
1answer
85 views
What software was used to make KDA - Villain?
I want to try making small clips with realistic environment with the lighting in the KDA music video...
Any ideas what kind of program to use?
0
votes
1answer
40 views
Calculating Material/Texture Placement from Bitmap to 3D Model
everyone!
I am currently developing a program that converts a 3D model to 2D isometric pixel art. Part of my program extracts the texture from an FBX file (as FBX files can have textures built in), ...
2
votes
2answers
81 views
Why do some videos look smoother and others don't on the same monitor
I have a Dell monitor with 60 Hz refresh rate and therefore games playing on it are not very smooth as compared to 120 hz.
But when I open videos on YouTube of the same game on the same monitor, some ...
3
votes
2answers
139 views
Mathematical Foundations of Radiative Transfer
I'm new to learning about ray tracing, but have been fairly confused by the mathematical foundations of it all. Specifically of radiometry/radiative transfer. I've internet searched a lot and skimmed ...
0
votes
0answers
39 views
3D Bouncing Cube
I'm trying to write a little program with a bouncing cube but I can't find the right x, y, z and angle for it. I have these lines:
...
2
votes
0answers
54 views
Atmospheric scattering band/seperation artifact
I am currently experimenting with some atmospheric scattering in glsl in my OpenGL engine.
I am experiencing a strange phenomena where a strange band / separation artifact appears along the middle of ...
2
votes
1answer
44 views
How are obj files textured?
I am a new learner in 3d graphics. So forgive me if I seem to ask something very basic. I am confused how obj files are textured. So far I have seen:
obj + jpg
obj + mtl + jpg
When I look online, ...
1
vote
3answers
92 views
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 ...
0
votes
0answers
23 views
0
votes
2answers
72 views
What exactly is it about reality that is so difficult to recreate in a 3D simulation?
I have to admit that, while watching footage of the enhanced 2020 version of the 2018 game Forza Horizon 4, when they are driving fast, I have to sometimes remind myself that I am watching a video ...
0
votes
0answers
45 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 ...
1
vote
1answer
47 views
projecting 3d onto 2d plane is not showing up correctly
I am trying to learn about 3d graphics from first principles, so i have decided to implement a simple thing, create a circle in 3d space & rotate it along some axis. I understand the basics theory....
0
votes
1answer
143 views
Vertices, Vertex Normals and Face Normals
Using Open 3D Model Viewer, I have converted an OBJ file to an STL file.
In the source file, the Vertex Normals are specified and in the destination, the face normal of the triangles are present which ...
0
votes
2answers
88 views
Rounding a 3D corner with Subdivisions
Following the instructions from this post on Stack Overflow, I have been able to find points A, B, and C from points V1, V2, and V3 and a radius value (code below). I would like to be able to find a ...
0
votes
0answers
30 views
Retaining hierarchy of assembly when converting STEP to GLTF
I want to convert STEP files to gLTF.
I know that gLTF suuports hierarchy of assemblies and parts.
Source: https://cadexchanger.com/blog/283-how-to-load-3d-cad-data-into-three-js-part-2
However, it is ...
2
votes
1answer
37 views
Blend Shape, Pose Blend Shape, and Shape Blend Shape
Since there is a lot of cross-section between computer vision and computer graphics for 3D pose and shape estimation of non-rigid objects, I would like to know what "blend shape", "pose ...
1
vote
1answer
33 views
Real 3D interior room from 360 images
If I have 360 images of an interior room from all different angles, would it be possible with current 3D software technology to create a real 3D representation of that room, where the camera could ...
2
votes
1answer
239 views
Detect collision for non axis-aligned bounding boxes
in my application, I needed to detect collision between 2 3D objects. To make it simple I can represent a object as a bounding box. So actually the task reduced to detect collision between 2 boxes in ...
4
votes
2answers
57 views
How to decide which way to triangulate a quad?
Apologies if this is a dumb question... but given four arbitrary (non-coplanar) points in 3D space, there are obviously two different ways to triangulate the quad that they form. One triangulation may ...
2
votes
3answers
142 views
How to Sample 3D Points Outside and Inside the Mesh Surface
I have a mesh of an object enclosed in unit volume cube and I would like to sample points inside and outside the mesh surface. What are the different ways of doing it? Is there any sample code ...
0
votes
1answer
81 views
Is there a term for this sort of graphics?
I'd like to try to write some C code to create similar animated graphics to these, which are from a very old Commodore 64 game called "The Sentinel". I've been researching but I can't seem ...
0
votes
2answers
67 views
Shear(?) matrix projection along Z (depth) axis
I'm creating a primarily 2d game (platformer perspective) with 2d background parallax layers. The parallax effect falls out of the fact that I'm positioning a bunch of layers in 3d and using a ...
0
votes
0answers
45 views
Clipping 3D Perspective matrix
I am trying to implement clipping in my simple renderer, but i have a trouble with setting the boundaries. I used the same projection matrix that is in OpenGL. The problem is, the vertices that are ...
0
votes
0answers
50 views
What's a good research topic in Computer Graphics?
I am currently trying to find topics for my master's thesis. I would really like to do something in the field of computer graphics, but I've been having trouble finding what are some current problems ...
1
vote
0answers
30 views
Principal component analysis on 3d points and other ways of capturing variance
So, I would like to do capture on 3d pointclouds of 3d models the planes/vectors where for each object we have the highest variance (i.e. for object represented by 2000 3d points I would like to get ...
1
vote
0answers
47 views
What modern C++ Unit Testing Framework do you use for highly parallel image, 3D and higher dimensional matrix processing workloads? [closed]
Most of the existing open-source libraries such as OpenCV, Tensorflow, and Pytorch use Google Test. I would like to know about strong alternative testing frameworks that thrive under a similar ...
0
votes
0answers
28 views
How to transform x-y-z red-green-blue arrows and draw them on 2D screen?
I'm making a raytracer and want to print debug arrows
Blender example:
Old version of 3d max:
How do I do the same having camera forward, up and right vector?
I think I need some kind of matrix ...
2
votes
0answers
64 views
Implementing monte carlo path traced refractions problem
I am writing a forward monte carlo path tracer with the added feature of specular refractions for transparent materials, I have managed to come this far but something is not quite right and I am ...
0
votes
0answers
63 views
Consistent Video Depth Estimation from Monocular Lens to approximate LiDAR?
If the iPhone had LiDAR sensors, it would be possible to generate a 3D point cloud that you could theoretically use to furnish a 3D AR reconstruction of your surroundings. E.g. you could create an AR ...
0
votes
1answer
47 views
Is it viable to create computer graphics via terrain scanning?
Couldn't find any resources on this, so I'll ask here.
For example, I want to create a game model of a mountain peak.
I took lots and lots of drone footage, almost from every side, photography ...
-1
votes
1answer
107 views
When do people need to work directly with a graphical API (eg: Direct3D) instead of using already made software?
I had this doubt in my head for several months and have been unable to find an answer anywhere on internet.
I know what OpenGL, DirectX, Vulkan, Metal, etc... are, I already know what they are used ...
0
votes
1answer
209 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 ...
0
votes
0answers
51 views
When do I need to use a triangulate function?
I have some misunderstanding about the modeling pipeline. In my mind pipeline are:
Concept
Sculpt
Retopo
Baking
Rigging
Setting
Animation
Game engine or cartoon/movie
...
I read many articles about ...
0
votes
2answers
126 views
What tris and quads need for?
I know that 3D artists make a 3D model with quads. And they advise to remesh with quads only (if it's possible).
So I have some questions:
Why do we use quads in CG (for games, cartoons, film, etc) ...
0
votes
0answers
58 views
How to create a 3D volume model from vtkImageData?
How can I create and save a 3D volume model from a volume image vtkImageData?
Some people recommend vtkImageDataGeometryFilter, so I tried the following:
...
1
vote
1answer
189 views
What is the reason that a boolean operation between two almost identical 3D triangular meshes fails?
I have been trying to detect defects on "before-and-after" meshes, by finding the boolean difference between them, to no avail.
I tried these two Python libraries(algorithms run in C++) but their ...
1
vote
1answer
119 views
glBindImageTexture returning INVALID_VALUE
I am currently having an issue with OpenGL as I am trying to load some vector information into a 3D texture. Currently, I am developing in OpenGL 4.6 which should support Image bindings.
this my ...
0
votes
0answers
53 views
Mathematics in Computer Graphics
Can you please recommend some topic for research work related to mathematics in CG?
(Maybe something like "Affine transformations in CG")
0
votes
1answer
62 views
Keep constant number of visible circles in 3D animation
I have created a 3D animation with a perspective projection of white circles moving randomly in a fake 3D space projected on a 2D computer screen (GIF 1).
Since I need to keep the same number of ...
0
votes
1answer
60 views
Looking for a compact file format for outputting 3D geometry with color support
I am looking for a file format to output some 3D geometry. In my case, it only needs to handle very simple shapes - uniformly spaced and sized cubes at points in space. So far I've ended up just ...
0
votes
1answer
75 views
constant pixel width for any scale
I have a standard 3d camera/projection/model setup that renders rectangles with a WebGL shader.
Users can zoom out and fly anywhere.
I want to make sure that regardless of the scale, width of the ...
