Questions tagged [raytracing]

Questions specific to raytracing (as opposed to scanline rendering), the 3D graphics technique of intersecting rays from the camera with objects in the scene.

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34 views

Combining two images based on their depth maps

Lets assume, we have two depth maps with us and their corresponding color maps. Now, our task is to populate a final image that will be displayed. Each pixel in the final image needs to be calculated ...
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28 views

Unity path tracing makes the pc crash

Good Morning. I'm testing Path Tracing techniques with unity, following this tutorial. http://three-eyed-games.com/2019/03/18/gpu-path-tracing-in-unity-part-3/ But I'm in trouble. Whenever I try to ...
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92 views

Given two 3d vectors, find the rotation matrix between the two

So I am making a raytracer following the very helpful online book of Gabriel Gambetta but I stumble on the rotation matrix part. My linear algebra background is 3Blue1Brown video series "The ...
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51 views

Magic number meaning in smallpt's camera ray calculation

In smallpt's source at line 90 the direction is multiplied by 140 and I was wondering where that number is coming from. I was hoping for it to be explained in the ...
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1answer
47 views

Buggy behavior when applying specular reflection

I'm very new to computer graphics and trying to implement a raytracer based on the book Computer Graphics from Scratch. When I tried to add specular reflection, I don't get the output that look like ...
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49 views

(Ray tracing) Trouble converting to screen coordinates, objects being stretched

I followed along with Ray Tracing in One Weekend and managed to get the final output but I wanted to understand more about creating a camera and "painting" the screen since he didn't go over ...
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29 views

Calculate Ray-Box intersections in terms of distance

Given a ray and a cube, how do I calculate the two intersections between them in terms of distance along the ray. Would be good if the results would be NaN or Infinity if they do not intersect. So far ...
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35 views

Path tracing: how to ensure the new direction vector is a valid direction vector with respect to a BSDF?

Given the BSDF function and the Normal vector of the intersection point in world space, how can I generate a new direction vector ...
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1answer
41 views

How to link Intel Open Image Denoise in Qt Creator and use it to denoise noisy Monte Carlo path tracing renderings?

I've been trying to link my the Intel Open Image Denoise libraries for about a week and still have no luck as of now. This could partly be because I am also novice in C++ stuff. So I need some help in ...
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91 views

Transforming a ray from camera space to world space

I am writing a Raytracer and generating rays from the camera. I have a working program but slightly confused about the linear algebra concepts involved in transforming the ray from camera space to ...
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1answer
21 views

Moving a vertex through the cursor

There is a way to move a selected point in a mesh with a cursor(assuming a camera that doesn;t change between frames). The way I remember the algorithm (but seems to be wrong) is: Unproject the ...
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68 views

Does film filter introduce bias in path tracing?

Does using box or gaussian filter introduce bias to the image when reconstructing the pixel? Bias does not seem to be talked in the Chapter 7.8 of PBRT
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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 ...
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38 views

How many years till photorealistic games? [closed]

I just saw this post by NVIDIA: RTX Global Illumination The images shown seem to be rendered in realtime which got me thinking about when games will achieve full photorealism and become ...
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35 views

Halton raytracer light path

I"m currently making my own graphic engine. I have the bsdf acquisition and various textures acquisition and I have materials suited for special type of light paths. did"t code the rendering ...
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34 views

Create a virtual server which use the full power of my GPU

i dont know if i can create a virtual server (with vmware, virtual box or with something like that), and if i can use the full power of my graph (i have a nvidia rtx 2080 super) or if I'm going to ...
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27 views

GL_OUT_OF_MEMORY Error when glDispatchCompute takes longer

I built a simple Ray Tracer which takes use of OpenGL's Compute Shader and traces ".obj" Files. The results are passed to the Host-Program via glMapBufferRange after finishing computing. ...
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95 views

Ray tracing where illumination itself affects the geometry

I am interested in a scientific application in which ray tracing is necessary, but also where the light itself alters the geometry of the surface mesh (imagine perhaps that the beams of light have ...
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126 views

Why is the image from the CUDA version not as sharp as the CPU version?

I am extending Roger Allen's Ray Tracing in One Weekend in CUDA (and also here) by following Peter Shirley's Ray Tracing: The Next Week; specifically Image Texture Mapping. The image I obtain from ...
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94 views

BVH uses aabb for a sphere in Ray Tracing: The Next Week

While studying Peter Shirley's Ray Tracing:The Next Week, I came across an issue that I cannot quite figure out: Stepping through the random_scene() case of the ...
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1answer
74 views

Debugging refraction in a sphere

I have been working on recreating some of the scenes from Peter Shirley's raytracing books using compute shaders and the new Metal raytracing API. It is going well but I am having some trouble with ...
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123 views

How do we know if a ray intersected a triangle in one in a million

I've taken a class about ray-plane intersection on this: https://www.khanacademy.org/computing/pixar/rendering/rendering-2/v/rendering-5 Suppose we shoot a ray at the scene and this scene contains ...
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76 views

Pathtracing - many bounces reduce shadows

I'm creating DXR PathTracer highly influence by Matt Pettineo's one - https://github.com/TheRealMJP/DXRPathTracer ; Relevant HLSL code below: ...
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91 views

Importance sampling GGX NDF - fireflies and bright final result

https://schuttejoe.github.io/post/ggximportancesamplingpart1/ - I have problem implementing this method. Somebody asked question about this before ( Can't understand the Importance sampling GGX ) ...
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76 views

Deriving radiance from irradiance and intensity

I'm reading PBRT and am stuck in chapter 5.4 about radiometry. In particular: We define the irradiance as the average density flux arriving at a surface with units $\frac{W}{m^2}$. So for a point ...
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89 views

Importance sampling a cosine distribution

Let's take a look at this blog article - https://schuttejoe.github.io/post/ggximportancesamplingpart1/ and image presented as a result of implementing it: Inside above link, you can see description ...
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175 views

Why does my image has a square pattern in cuda path tracer?

I am writting a path tracer in cuda following the Shirley's book. I am having a square pattern as an output. The size of the block change if I change the block dimensions. For this image, the block ...
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104 views

Path tracing - cannot converge diffuse sampling + oversaturation

I'm in process of creating progressive path tracer using DX12 + DXR. I managed to create working raytracing code + pathtracing code with multiple bounces but I'm experiencing problems stated below (...
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1answer
51 views

Worsening sampling quality of raytracing with increasing distance from world origin

I am using RT shader (DXR) to generate g-buffers with code below. There was no problems with smaller scene (pink room from cwyman tutorial - http://cwyman.org/code/dxrTutors/tutors/Tutor5/tutorial05....
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75 views

What should I do when a new sampled direction is below a normal oriented hemisphere?

I generate random directions from the pdf of D term in GGX BRDF. On the picture, white dots are new directions and the cross is the light direction, with roughness = 1. What should I do with the ...
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46 views

Global root signature crash

I have a problem with RTPSO creation. Using local root signatures for each of rgs (ray generation shader), chs (closest hit), miss is working correctly. However, for performance sake, I want to use ...
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97 views

BVH works fine, but why does it slow down a lot when using Cornell Box? How to improve it?

I am using the SAH-BVH from PBRT-v3, it works fine for triangle-mesh, especially for dense mesh. But here is a problem. If I added Cornell box while building the BVH tree, the BVH performance will ...
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137 views

Ray Tracing, why does the GGX make my rendering result darker and darker for each frame?

I am trying to add GGX and PBR textures to my GPU ray tracer. The result is very strange, it's getting darker for each frame. ...
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92 views

Raytracer help - Background color writing over some colors?

I'm implementing Peter Shirley's "Raytracer in a Weekend: The next week" and I'm having some trouble with rendering a scene with a light. I'm not sure if the issue is the background color or ...
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1answer
49 views

Hit group - export already defined

I am getting this error when creating RTPSO with multiple hit groups: ...
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58 views

Euclideon Unlimited Details Voxel Engine Architecture

As I understand Euclideon haven't just rendered voxels for these infamous demos, since the amount of geometry is still too large for the 2010 PC with software raytracer and the model taking whole HDD ...
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72 views

How does one obtain SDF of an octree?

As I understand the usual practice is to obtain the SDF by the means of a KD-tree. But the KD-tree generation and the lookup (for each ray step) are, well, slow, while the octree can be easily ...
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1answer
47 views

Texture value clamped to 1

I am working on ray/path-tracer using DXR and I'm starting with simple AO. In first pass, I am storing normal value and RayTCurrent(): ...
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969 views

Is BVH faster than the octree/kd-tree for raytracing the objects on a GPU?

Apparently most people use BVHs in their raytracers. The ray-AABB intersection code is very fast and and the BVHs also compresses empty space efficiently, working even with infinitely large objects, ...
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2answers
283 views

Why is eye-based ray tracing preferred over light-based ray tracing?

It seems that virtually all path tracers use eye-based or view-based path tracing. That is, the light rays originate from the camera rather than the light source. The reason given for this everywhere ...
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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 ...
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1answer
78 views

Rendering moist/wet materials like human anatomies for surgical simulators

Real human anatomies look wet/ moist when operated. I am looking for some good methods for rendering anatomies in a virtual simulation, and hence I have done a literature survey on 'Rendering wet ...
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1answer
93 views

Math for adaptive supersampling for raytracing

How do I determine how many (jittered) rays to trace for a given pixel, as a function of the statistics of a small initial set of test rays? Also, what size should the initial set be? (it's currently ...
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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 ...
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1answer
73 views

Ray Tracing Bounding Volume Hierarchies nodes

I'm new to computer graphics programming so I apologize in advance if my question is stupid. I'm trying to implement a BVH for my ray tracer and I looked at some lectures explaining BVH. They all ...
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2answers
57 views

Weird patch on reflective spheres on planes in raytracer

I am writing a small raytracer in python , everything was working fine but when i implemented plane geometry then the reflective spheres are getting weird patches on lower bottom. image below: I ...
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1answer
117 views

Prove radiance contributions of deeper paths fade away

When ray tracing, I find it intuitively clear that deeper paths have a lower contribution to the overal picture than shorter paths. This is the main reason why it is generally okay to render a picture ...
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83 views

Why is my ray caster is running much faster as a fragment shader compared to a compute shader

I'm trying to write a simple ray caster in OpenGL with C++. Previously, I have been using the fragment shader of a quad that covers the entire screen to do all the ray calculations. Now, I want to do ...
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1answer
115 views

a very simple raytracer is giving a black output which is implemented in python

I am trying to implement a simple raytracer in python. I am following this tutorial here here is my code, i have explained in comments the relevant parts .All i am getting is a blank image. ...
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124 views

Understanding of Microfacet monte-carlo path tracing

I am trying to implement BRDF microfacet path tracing and I think I need a little push. I will explain what I understand so that you can correct my mistakes. I start with simple rendering equation: ...

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