Questions tagged [3d]
Questions and problems dealing with three-dimensional space, including 3D meshes and other data structures, vector math, transformations, etc.
309
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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 ...
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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 ...
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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 ...
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2
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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 ...
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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 ...
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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 ...
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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 ...
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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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289
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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) ...
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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 ...
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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 ...
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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")
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119
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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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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 ...
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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 ...
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Graphics engines during the sixth console generation
From my understanding game developers used mostly proprietary, in-house graphics engines during the sixth console generation (Xbox, PS2, GC, DC) on a game to game basis. Why didn't standard engines ...
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What is it that really prevents photo-realistic, real-time, digital 3D simulations?
Ever since I was a small child, seeing the amazing 3D visuals that developed in the 1980s and 1990s, I was certain that photo-realism was "just around the corner". In the year 2020, I certainly ...
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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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Turning layered curves to polygon mesh?
I am confronted with the problem to render 3D representations for objects marked on microscope slices.
So I have a set of aligned polygons in parallel planes from tracing the outline of the object in ...
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1
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Y axis inversion in 3D rasterization
What is the correct way to invert the y axis during the 3D projection?
I see a lot a people doing:
...
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250
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After making any 3D model using Opengl how to export it's data in .dae file?
I'm trying to make simple 3d modeling program in c++ with Opengl. So I don't know how to transfer/convert/export or save data of 3D model in .dae file.
NOTE:- 3d model is made using Opengl ...
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1
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954
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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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104
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Estimate 3D cube pose after camera rotation
I have some photos of 3D cube. I also know the 3D pose of the cube in each photo (yaw, pitch, roll).
I want to estimate the new pose (yaw, pitch, roll) of the cube after performing 2D rotation to the ...
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Understanding the near clipping plane
I don't understand something about the near clipping plane. It's there to avoid the division by $0$ but when we compute the pixel coordinates, we just need to multiply by the clipping plane to clip ...
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284
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BSP tree rendering
As a little project, I'd like to implement a BSP merging algorithm for Boolean operations on solids. But to even tell whether it works, I need some way to render the BSP tree. In other words, I have a ...
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What are "Triangles" in 3d modeling?
In 3d modeling, there is some "triangle count" which determines complexity. I am not sure but I think cubes have 12 triangles or somethong. But I see NONE. They have squares, no triangles! Can someone ...
user11352
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299
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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 ...
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414
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Why is the z direction away from the screen/viewer?
I wonder what is the reason that when z increase, the objects appear far away and when z is negative, the object is behind the camera?
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Visualize the interpolated unit quaternion on the surface of the unit sphere
My major is mechanical, please forgive me for asking questions that may seem trivial to you.
First, I'm reading the following paper:
Dam, Erik B., Martin Koch, and Martin Lillholm. Quaternions, ...
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186
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Compute Speed of Spheres in 3D animation
I have created two animations:
One where a "camera" moves towards the spheres creating an optic flow (1st GIF).The code can be found here.
One where spheres move randomly in a 3D coordinates space (...
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367
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Rendering equation for spherical lights
I am currently implementing spherical lights in my DirectX game engine. I decided to build the shading formula from the classical rendering equation. Here is what I get:
The simplifications show that ...
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68
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Apply a pose to a 3D model/mesh
Assuming that I have pose information for a human, is there any ways/tools to apply that pose to a 3D model?
Basically, given continous pose information say from a dancing person, I like to animate a ...
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63
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Calculating normals for vertices which aren't a vertex of all neighbouring triangles
In my procedurally generated mesh in Unity, not all vertices are vertexes of all neighbouring triangles - essentially, it's a grid with cells of varying sizes. This is messing up the calculation of ...
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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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Why does my code generate a figure whose kurtosis looks a little higher than the one I am trying to reproduce?
this figure (fig_1) is an univariate normal distribution in 3D, the corresponding equation is in the top left hand corner
it seems that x varies from -5 to 5; sigma varies from 0 to 4.
This Python ...
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Why does my code to plot a cone actually generate a roof?
per this post, this formula
$Z = 1 - \sqrt{X^{2} + Y^{2}}$
generates a cone where the point is at (0, 0, 1) and it spreads out below that. It meets the x-y plane at the unit circle
I am trying to ...
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Could some give an explanation or hint about this kind of equation? $\left(- \sqrt{X^{2} + Y^{2}} + 1\right) \cos{\left (2 \pi X + \phi \right )}$
This is a screen shot from an animation generated by a matplotlib example
the key part in the code is
...
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2
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283
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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 ...
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What's the difference between Clipping and Culling?
In a tutorial about OpenGL both words are mentioned, unfortunately without a good explanation.
To find out, I have read this article three times, but I fear I'm a too common man... my understanding is ...
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643
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Calculating the angle between two polygons
For my application, I want to render models as polygonal surfaces in 3D space and have edges that are bent "outwards" to have a solid line and those who are bent "inwards" to have a dotted line. So if ...
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What is performance better - add four materials to mesh or duplicate every vertex and use packed texture?
I am making ski jumping game (in Unity) with procedurally generated hill mesh. I want to add lines on hill like this (mesh is created by script, but I've manually assigned materials in Blender)
...
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How can I detect if an edge has flipped during the UV unfold process?
I'm writing my own UV Unfold operation (similar to Maya's Optimize UV tool or 3DS Max's Relax Tool). My code works great 90% of the time but in some instances, I'm getting faces and edges that flip ...
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497
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Help with understanding the look-at function (the view matrix)
I've been reading this article about the look-at function. I don't understand the part when they're trying to inverse the matrix N.
They say that R is orthogonal because all its row and column ...
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How can i wrap the earth image around a 3D Sphere using OpenGL, GLFW, GLAD, GLM?
Please help me out with this thing and currently i am a little more than a beginner so please tell me in that context. i don't need any obsolete methods for creating this like using GLUT or GLEW.can ...
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What are the i,j,k components of a 3d mesh on plot.ly (online)?
A 3d Mesh on plot.ly online graph maker (https://plot.ly/create/#/) takes 3 mandatory variables (X, Y, Z) and 3 optional variables (I, J, K).
I understand that if I want to draw a cube that I then ...
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252
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Why don't I see tile-based 3D graphics?
As we know, tiles can make it quicker to update large portions of the display at once, as compared with a bitmap. To put, say a letter, on the screen, the Commodore 64 typically does two writes (the ...
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Programmatically generating bin files for GLTF models
I have a need to generate a series of GLB files. I have a base template for a GLTF file which I have to derive off of. The models thus generated will only have varying textures on them. The base mesh ...
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334
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Using octree for cheking intersection of ray and meshes
I wrote the code for checking intersection of ray and meshes on scene. It consist of two parts - broad phase and narrow phase.
In broad phase I build an oriented bounding box around each mesh and ...
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2k
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Vulkan: efficient way to update VBO mesh vertices?
I would like to change/add/remove some mesh vertices in existing VBO's (while deforming and remeshing 3D objects) . With OpenGL I would have to reload whole vertex VBO's. I suppose with Vulkan there ...
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Unfold a 3D mesh to a 2D plane
I'm trying to unfold a 3D mesh onto a 2D plane. My general idea to do this, would be to cycle through all the faces of the meshes and perform a hierarchical transformation.
So I would start at the ...
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