Questions and problems dealing with three-dimensional space, including 3D meshes and other data structures, vector math, transformations, etc.
0
votes
0answers
8 views
Open Stereoscopic Player Full screen in second monitor
I'm trying to create a WinForm application with C# programming language that opens a media file in Stereoscopic Player while clicking a button after choosing a file path through an openFileDialog ...
0
votes
0answers
34 views
Help LOD:ing a tiled 3D model of a city
I have a 3D model of a city, divided into ~7000 adjacent tiles, taking up close to 100 GB in total, including fbx files and textures.
I want to convert this into a model with different levels of ...
0
votes
0answers
30 views
Dragging an object on a plane with respect to the camera
this is a long description but I hope the solution is simple:
I have a 3D pointCloud with a vtk box (displayed at 0,0,0) and I want to drag the box on the XY plane with my mouse cursor (Zero movement ...
0
votes
0answers
13 views
Merge multiple Point Clouds into a single 3D object
I am testing the Intel RealSense D435 camera and have been able to create multiple Point Clouds (.ply) of a certain object. Each Point Cloud is taken in a different viewing angle of the object.
Now I ...
1
vote
2answers
42 views
If a 3D scene is rendered onto a hemispherical display, will there still be warping near the edges?
When a 3D scene is rendered to a 2D display, the image is distorted near the edges of the display.
If a 3D scene is rendered onto a hemispherical display, will there still be warping?
7
votes
3answers
174 views
How do graphic engine developers debug their 3D graphics code?
I'm currently trying to create an amateur game engine, and I often run into very basic bugs (eg I change the node hierarchy code and suddenly nothing is displayed). Some of the methods I will use ...
2
votes
1answer
44 views
How to display edges in a 3D file on Facebook
I'm trying to show a 3D model on Facebook and display its edges and lines. I found that I could export a 3D model from Sketchup using glTF Export plugin to a glb file that I can drag and drop in a ...
0
votes
1answer
81 views
Which techniques do I need to animate a 3D model in my homemade engine
Suppose I am making my own C++ 3D engine; I can already load a 3D model using assimp, display it with phong lighting, and I now want to animate it.
I'd like features in my engine to, say, load a run ...
0
votes
1answer
63 views
How to compute volume of intersection of non-axis-aligned cuboids in 3D?
Given two cuboids in 3D space (8 vertex coordinates each) that are arbitrarily oriented, how can we find the volume of overlap between them in the fastest manner?
0
votes
0answers
19 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 ...
3
votes
1answer
59 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, ...
1
vote
1answer
75 views
How to rotate a camera?
So I am doing a simple FPS camera with openGL. I store the camera as 4 vector, a position vector, a lookAt vector, an up vector and a right vector. When the user presses a key, I create a rotation ...
1
vote
0answers
91 views
Efficient operations on polyhedra
I currently perform several operations on polyhedra with cgal. These operations include
Union of two or more polyhedra
Difference of two or more polyhedra
Intersection of two or more polyhedra
...
1
vote
0answers
57 views
Image Processing: Photogrammetry [closed]
I am new to image processing but I am currently exploring myself in 3D reconstruction during my leisure time.
I have decided to use openCV (eg. edge detection, possible?) in C++., maybe with a little ...
1
vote
1answer
101 views
How to interpolate vertex normals for Phong lighting when barycentric coordinates are negative?
I'm interpolating normals for Phong lighting models. Since I am calculating in the light of each pixel, I'm doing the interpolating after the viewport transform has been applied. So I save a version ...
1
vote
2answers
82 views
How to calculate the view vector in Phong Lighting Model?
All the books and reference I have read say that the view vector is calculated by subtracting the point where eye is at, from the point where we want to calculate light. But since, eye is at (0, 0, 0) ...
2
votes
1answer
58 views
Do normals in obj files have to be changed into eye coordinate before being used?
Obj files give pre-calculated normals which are in model coordinates. So I wonder if they have to be transformed into eye coordinate (where I use them to calculate lighting)? I'm thinking yes because ...
5
votes
2answers
194 views
How did the hard, accurate shadows, work in early 3d (2000 - 2004) games?
I've been hunting around the internet for a while now, and I can't find anything about the specific shadow technique that I'm looking for.
I can only recall one game in particular that used it, and I ...
1
vote
0answers
49 views
How to do clipping in camera space?
I don't even know where to start. So far, the only progress I have gotten is checking the z value of each vertex of each triangle. If all three vertices' z values > absolute value of far or < ...
1
vote
2answers
100 views
Is there something wrong with a column camera matrix?
I am writing a simple ray tracer. I was working on my camera matrix when I encountered a problem. When I changed the look vector, so that it headed down, the image, which was supposed to go up, ...
1
vote
3answers
130 views
What is the use of homogenous divide?
This question perhaps has been asked and answered a thousand times, and yet I haven't found any that satisfy me. The reasons are often these:
1/ You need a 4 dimensional vector to work with 4x4 ...
-4
votes
1answer
36 views
How is the generalized quaternion rotation operator is drived?
enter image description here
I Would Thanks if u guys help me
1
vote
1answer
644 views
How to derive a perspective projection matrix from its components?
This has been haunting me for several days now. I want to find the component that makes up of this 4x4 perspective projection matrix, with $l$(left), $r$(right), $b$(bottom), $t$(top), $n$(near), $f$(...
1
vote
0answers
50 views
How to automatically project texture from high poly mesh to low poly mesh?
I have two aligned meshes: I have exact mapping from each vertex of low poly mesh to surface of a high poly mesh. High poly (~100K vertices) mesh is non-manifold, low poly (~1K vertices) is manifold ...
1
vote
1answer
75 views
What technique would I use to create fake 3d walls as seen in Realm of the Mad God
I wanted to make a little demo for a console with Realm of the Mad God esc graphics to brush up my C and SDL skills.
One problem I'm running in to is creating the 3D walls.
The console I'm ...
2
votes
0answers
41 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 ...
4
votes
1answer
106 views
why is translating in 3D space the same as shearing in 4D space?
I was reading "3D Math Primer for Computer Graphics and Game Development" and there was something the author had said that I thought was particularly interesting, he stated
It is important to ...
1
vote
0answers
45 views
How does anti-aliasing work, in general, for raytracing? [duplicate]
I am working on a raytracing Java program for fun. Here's one rendering:
As you can see I still have to implement anti-aliasing (and there are huge geometry problems I won't get in to). How would ...
3
votes
1answer
67 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 ...
1
vote
0answers
99 views
Composition of an .obj file
Using an iPhone X, I can get a mesh of the face (using ARFaceGeometry), which I can output as an .obj file using ...
1
vote
2answers
138 views
Does this 3D rendering method exist? How is it called? Is there any C++ algorithm for it?
I've been thinking about making my own 3D rendering engine in C++, but I don't know much about math that's required to do it. I'm not even sure if it's possible or if it even exists or how it's called....
1
vote
1answer
185 views
How can I use 3d animation to create a character that uses sign language?
I performed a quick search on programs that translate natural language to sign language (through a 3D animation character). Here are examples:
IBM SISI
ProDeaf (which is an android app)
My question ...
4
votes
1answer
140 views
Was Evans & Sutherland CT5 really created in 1981?
A few days ago I found a video on Twitter showing the Evans & Sutherland CT5 Flight Simulator system. It was labeled as 1981 footage and looked really amazing. The first time I saw similar 3D ...
1
vote
1answer
49 views
Stereoscopic 3D app development
I want to create an application to visualize image pairs in stereoscopic 3D. I want it to have a cursor that can move left and right, but also in and out. I think the way to achieve this is to draw a ...
6
votes
1answer
275 views
Why do I need to inverse the orientation matrix of a camera to be able to translate it in the direction it is facing?
I've been going over some OpenGL learning resources and one of them is this article: Modern OpenGL 04 - Cameras, Vectors & Input in which the author presents an approach to building a ...
-1
votes
2answers
124 views
The distance from the cube sides to the parallel projection plane
I have asked this question on ru.stackoverflow.com and have no valid answers.
Specification:
Coordinate system
Cube spins around its center on all three axes.
Turn angle is not known previously.
...
3
votes
2answers
463 views
Inverse-Transpose of Vertex Normals
For the past month, I have been learning on my own and writing a little graphics library and am currently working on the transformation of vertex normals to soon support lighting/shading. I understand ...
10
votes
3answers
940 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 ...
4
votes
3answers
535 views
Point of view and rotation
Two questions which cross over maths/3D imaging/computer science. I'm trying to describe a point of view of an item in a 3d space and subsequently its rotation in a paper I'm writing. Versions I've ...
2
votes
0answers
83 views
Rendering of large STL files
I am in the process of creating some software in Java for generating 3D gear geometry and saving it as an STL file. I am looking at a means of drawing the geometry so that the user can view the ...
1
vote
0answers
63 views
Algorithm for clipping convex quadrilaterals
I'm dealing with hardware that uses quads as its polygonal primitive. Not triangles. A triangle can be expressed by setting 2 of the 4 vertices equal to each other for a degenerate quad.
For the 3D ...
4
votes
1answer
157 views
How to correct point cloud distortion
I am using Unreal Engine to export custom render passes for the scene depth in world units. Every pixel in the render pass has a value which is the distance from the camera to that pixel in standard ...
1
vote
2answers
180 views
How to use multithreading in 3D software renderer to speed up fetching texture values
The biggest bottleneck of my code is fetching texture RGB values from memory.
My code looks something like this:
...
1
vote
0answers
109 views
Applying 3d transformation to cuboid
I have the 8 vertices of a cuboid (red points)(XYZvox) with known distance in millimetres (vox to mm) between each vertex which I transform in 3d space using the 4d transformation matrix (M). I am ...
1
vote
0answers
257 views
Convert prc-file (3D PDF) to 2D file format
I have a question regarding 3D PDF files.
I have a 3D vector graphics image which is saved as a Product Representation Compact (PRC) file. The PRC file is embedded in a PDF file. I can view and ...
1
vote
2answers
324 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 ...
1
vote
0answers
39 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?
6
votes
1answer
104 views
3D projection that increases objects' size as they become more distant
tl;dr Is there a name for a type of (non-physical) projection that causes objects to become larger the farther they are from a camera?
With a fisheye projection, an object twice as far from the ...
5
votes
1answer
226 views
Rotation matrix for a 3D object in space
This is the follow-up question from here: Minimum requirements to uniquely represent a 3D object in space
Assume I have 3 original points in a 3D object (in 3D space) as ...
4
votes
2answers
210 views
Minimum requirements to uniquely represent a 3D object in space
Let's assume we have a 3D object (in 3D space). We get a single representation vertex from this whole 3D object. Given the fact that the object can be moved and rotated in the space in any direction, ...
