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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47 views

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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2answers
71 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 ...
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18 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 ...
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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 ...
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1answer
75 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 ...
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1answer
67 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 ...
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3answers
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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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1answer
67 views

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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1answer
31 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 ...
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2answers
54 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 ...
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1answer
24 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 ...
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1answer
103 views

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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3answers
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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 ...
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2answers
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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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5answers
15k 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 ...
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1answer
58 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 ...
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1answer
252 views

Rendering 3-D point clouds obtained from depth maps as a 2.5D video

Suppose I have code to generate a bunch of frames, each of which is a depth map(I have access to the matrices which represent depth) which in turn is used to generate a point cloud. One frame would ...
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1answer
151 views

qt - view geomview (.off ) file

I want to open a .off file and view the content 3d model using libQGLViewer, qt-creator. I don't know how to display the 3d model after opening its .off file. ...
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1answer
80 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 ...
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1answer
86 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 ...
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1answer
53 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 ...
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0answers
37 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 ...
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1answer
41 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 ...
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2answers
531 views

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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1answer
88 views

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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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 ...
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2answers
349 views

Why smoothed meshes in 3D studio end up with the same number of vertices/triangles? How then can they be smoothed with the same geometry?

I am trying to understand why meshes that are smoothed in 3D studio (Modifiers/Smoother) end up having the same amount of vertices/faces before or after that process, as well as the exact same ...
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0answers
29 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 ...
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0answers
56 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 ...
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0answers
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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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0answers
53 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 ...
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0answers
24 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 ...
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1answer
42 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 ...
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1answer
102 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 ...
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2answers
89 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) ...
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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 ...
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0answers
34 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: ...
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1answer
90 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 ...
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50 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")
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How can I draw this style of grid?

I'm trying to write code (in any language) to render this 3D grid, matching the look and colors as closely as possible:
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1answer
722 views

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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1answer
71 views

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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2answers
303 views

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 ...
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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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1answer
50 views

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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2answers
5k 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 ...
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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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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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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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