Questions tagged [3d]
Questions and problems dealing with three-dimensional space, including 3D meshes and other data structures, vector math, transformations, etc.
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Conversion from W/cm2 ( or W/m2) to W/sr
I was reading a thread where you have comprehensively answered about radiometric units (Deriving radiance from irradiance and intensity).
My question is whether we can convert from W/cm2 ( or W/m2) to ...
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Point a normal vector towards a point in 3D-Space
Given a normal vector in 3D-Space, how can I rotate the vector, such it points to a point in 3D-Space.
I tried couple of ways doing this, which ended up looking completely wrong.
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Defining "inside" and "outside" of a 3D space
I am not sure if this is the correct SE to ask this question. However, lets say I have been given 3D models of several enclosed spaces.
I want to populate spaces with, lets say, planes flying through ...
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how can I estimate the depth of an object with a bound box from just a few images where i moved it?(knowing how much i moved)
how can I estimate the depth of an object with a bound box from just a few images where i moved it?(knowing how much i moved)
For testing purposes I have a cube and a camera perpendicular to it and I ...
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Is it possible to set visible and color for all 12 edges(spines) of the figure (cube) in matplotlib?
In 2d, matplotlib plots all 4 edges(spines) of a figure.
In 3d, matplotlib plots 9 out of 12 edges of a cube.
Is it possible to set visible and color for all 12 edges(spines) of a cube in 3d?
I ...
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Convert point clouds into voxels
I have points that are obtained by sampling a mesh(which is not watertight). Now, I would like to convert that mesh into voxel?
Does anyone have any suggestions for solving this problem?
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Can STEP files contain polygon data? How do I get a smoother mesh out of a STEP file?
I am trying to work with a .STEP file I have received. Upon opening it in CAD Assistant, I find
its surface as jagged lines, like a low poly model. When I export it as OBJ from there, the edges and ...
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How to retrieve a mask for a partially filled 3D Truncated SDF based on its ground truth?
I am trying to create a mask which is required for a 3D inpainting task. My data contains 3D truncated SDF grid of size 64*64*64 with a truncated value of ...
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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 ...
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Intrinsic Matrix vs Perspective projection matrix
I was going through the camera matrix explained in the wikipedia article and understand how the matrix K \begin{bmatrix}f_x&s&x_0\\0&f_y&y_0\\0&0&1\end{bmatrix} is built. The ...
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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 can I raycast with chunks?
I am attempting to implement chunks/octrees to speed up my render times. However, sometimes the walls show horizontal or vertical lines (rays hitting the inside of voxels?) or some blocks disappear ...
CommunityBot
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Object appears in unintended parts of the screen when using manual WorldToScreenPoint
Hy guys I'm new to 3d graphics and i lack some Linear algebra knowledge. I tried to recreate Unity's worldToScreenPoint method with kotlin on android. I copied some code from their forum and wrote ...
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HTML Canvas not drawing
I'm working on a 3D Renderer with the canvas element and JS but currently the cube I made is not rendering. I currently have it set to just render a wireframe of the cube and am hoping to render the ...
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Creating a UV Map for a 3D Cone
I have the following problem I am currently facing.
I am creating the vertices for a cone based on the number of segments and the radius of the base and top.
This is done as follows:
...
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Rotating a set of cameras to look at a rotated object
I'm trying to use Instant NGP on a synthetic image dataset. I have image sequences of a moving object with the following information:
I have the object's xyz and the camera's xyz positions in a void.
...
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View rotation matrix
Im unsure about how I could describe what im trying to achieve in few words or a title so ill go on to describe it.
So I have voxel, in 3D space, represented solely by its center.
The voxel though, is ...
CommunityBot
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3D engine projection distortions
I'm trying to write my own 3D engine using Python and Pygame.
I have successfully implemented rotation and projection matrices to display 3D models. However I am so far unable to implement translation ...
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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 ...
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Patchy patterned artefacting in depth buffer
I am writing a polygon rasterization renderer. Some meshes render flawlessly, but some produce strange artefacts in the depth buffer. These artefacts do not just appear when I save the depth buffer ...
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How to setup a 3D camera
I'm trying to figure out how to setup a 3D camera in WebGL. This is my first swing at 3D so a lot of the matrix stuff is new to me.
Code
The code can be reviewed in this CodePen: https://codepen.io/...
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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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3ds max: Z-fighting when working with Large Objects
I had a z-fighting/z-clipping issue with a scene containing some very large objects yesterday in 3ds max. It can be seen in the image below:
For some reason downscaling the scene significantly (a ...
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Cropping a .usdz file
I have a program that is creating usdz 3D models from real world objects. I would like to be able to crop those objects in 3D space to remove extraneous nearby objects or walls. Is there a good ...
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How to derive Field of View (FOV) angles from a 2D projection
I'm looking for some guidance.
I'm not sure if this is possible, and I'm not sure where to start.
I need to measure the FOV angles of a first-person, 3D game using only gameplay screenshots.
I'm bound ...
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Is depth of field incongruous in a 3D still image?
If rendering an image in 2D, adding depth of field effects (blurring objects further from the focal distance) adds realism and draws the eye to the object of the image. With a 3D (i.e. stereo) image, ...
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Unknown array of floating point numbers. View matrix?
I want to control the camera in an old game using head tracking (TrackIR, opentrack, etc.), such control was not provided by the game engine. I'm trying to find the camera coordinates and rotation ...
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Optimized 3D rendering using dots and/or line segments of different sizes in Scratch
I'm developing a 3D rendering engine in Scratch, which is a block-based visual programming language. It does not have any support for bitmap rendering, but there is a "pen" plugin that lets ...
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How to display real time 3-D orthogonal vector rotations?
I'm an embedded developer here with very little experience in computer graphics. I'm currently working on a GUI that can display a calculated inertial solution at run time. I have hardware that can ...
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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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Why are the transformations of an object calculated on CPU?
If I understood correctly this is the process of rendering an object:
Array of 4d vector defining points 3d points(with the fourth component 1) representing object's vertices in object/local space:
<...
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Export Model Textures Per Face
(Note that as far as attempts go, I can't find anything that helps me)
I have a 3D polygon, and for simplicity's sake it's going to be the one below:
It is textured using the UV map below:
Side ...
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Glowing objects in a raytracer? How it works?
My raytracer has a point light source, it works as it should, illuminates the scene, but there is a problem, it is not visible, I would like to add glowing objects to the raytracer, for example a ...
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How to convert from world coordinates to camera coordinates
In the world coordinate system, there are objects with rotation values rx1,ry1,rz1 and position values px1,py1,pz1.
Similarly, ...
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help with libgil tutorial (python binding)
could you please give me some guidance on following this libgil tutorial? https://libigl.github.io/libigl-python-bindings/tut-chapter0/
The problem: When I do the first example (two yellow triangles), ...
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Approximate compass bearing of a normal
Let's say I have a 3D model that represents a small real-world space; it could be bounded by a 10" by 10" by 10" box. I know the real-world compass bearing for an observer in the center ...
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Trouble getting a raytracer camera representation for different aspect ratios
I am trying to make my camera representation work for images whose aspect ratio isn't 1 (640x480, 1920x1080...), but I am having some trouble getting it to work.
The camera model is pretty simple, as ...
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Camera Perspective of 2D X/Y Plane
I'll start with the coordinate system I'm trying to use: If I were standing on the ground, facing north, the x axis is a line moving from the west to the east (positive X is east). Positive y is ...
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Starting from a basic glTF (such as a static sphere or plane) exported from Blender how can I add an animation manipulating its JSON?
I'm working on a glTF, precisely I'm trying to animate a "static" mesh exported from Blender directly acting on its JSON.
In doing so, I'm following the logic used in this tutorial , where a ...
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Identifying an openGL 3d model
I currently have an application that uses openGL in order to render a 3d model of a car.
I would like to change the car models but I have no clue what format my application uses.
The current format of ...
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Is a line drawn using vectors, triangles or polygons within OpenGL? [closed]
Trying to understand how OpenGL generates what is seen as images & graphics and these questions come up.
Are 3D lines (which should be drawn using vectors) drawn using triangles or polygons? Or ...
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Convert one triangle to another in matrix4x4?
The context openGL instances learning.
I want to transform a reference triangle to another one. So final goal is to have one triangle and the instance being a transformation of that initial triangle.
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What is the proper term for 3D models which are similar but not necessarily the same size, orientation, face-count/tesselation, etc?
Sup[pose I have a model of a unit cube (12 faces) aligned to the three axes, and another model of a cube divided into thousands of faces and hard-coded in a random orientation. They are both cubes, ...
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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 ...
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Historically Significant 3D Bicubic Patch Data?
The little milk pitcher / jug in Martin Newell's 1975 PhD thesis “The Utilization of Procedure Models in Digital Image Synthesis”, does anybody have the bicubic patch data for it? The teapot's data (...
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Finding Camera projection matrix from known input and output
Lets say I have a rectangle with known coordinates in 3D scene, and I'm projecting it using pin point camera to the plane (screen).
You can imagine it deforms on the screen per camera transformation ...
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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 ...
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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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