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.

Filter by
Sorted by
Tagged with
0
votes
0answers
59 views

Rendering equation - brdf / pdf > 1?

I am creating a path tracer and I got some strange results when calculating the strength of light. I am using a rendering equation inspired by this diagram: When I use the cosine everything gets ...
2
votes
0answers
30 views

Sparse voxel oct tree tracing, optimization tricks?

I have a working oct-ree raytracer and I am applying it to the sponza. The algorithm I have designed works like this at a high level: Collide with the bounding box of the model, move your ray to that ...
3
votes
1answer
60 views

Next Event Estimation for Triangle-based Light Sources

I have a question regarding the NEE for light sources that are composed from triangles. I implemented the next event estimation (explicit light source sampling) for spherical light sources but after ...
1
vote
0answers
68 views

Why my bsdf can not pass Chi2test?

I implemented a MicrofacetTransmission in nori. But it can not pass all Chi2test when alpha is large(>= 0.4 or ?),part of chi2test is passed.And I can not found the problem.Can someone help me? ...
2
votes
1answer
55 views

What to do with reflected rays that don't intersect?

I implemented reflection on my ray tracer. I had very few objects in the scene, so the reflected rays would less likely intersect. If most of the rays don't intersect, metallic objects would appear ...
3
votes
1answer
57 views

Hard Shadows with Dielectrics/Transparency

I am writing a raytracer which is meant to support shadows. Previously, I have naively implemented hard shadows by casting a shadow ray towards the light (+ offset) and seeing if it hits anything ...
1
vote
1answer
41 views

Are intersections still hardware accelerated if we define a custom intersection program in Optix?

I've stumbled into Optix samples that define their own intersection programs to define how primitives intersect (or don't) with a ray, and others (mostly those only dealing with triangle meshes) that ...
6
votes
1answer
103 views

Can meshes be reused in raytracing?

In rasterization, at least in the context of game development, it is a common to have many instances of the same 3D object in a scene (think many identical rocks in different sizes/positions/rotations)...
0
votes
0answers
41 views

ray triangle mesh intersection triangles inverted

I'm trying to render a dodecahedron triangle mesh and the triangles seem flipped or mirrored somehow. The first picture is what I should be getting, the second picture is what I'm getting and the last ...
1
vote
0answers
84 views

Time Interval Ray Tracing performance

I found a very nice paper regarding Time Interval Ray Tracing for Motion Blur published in 2017. That was before RTX GPUs were on the market. I have a few questions about an optimal implementation and ...
0
votes
0answers
21 views

obj to grd sdf generators?

I am trying to generate sdfs from objs but when I try to use the only tool I find online it segfaults on even the simplest inputs, such as the blender cube. Does anyone know of a tool to generate grid ...
1
vote
1answer
77 views

question about true Lambertian reflection in Ray tracing in one weekend

I have a question about Peter Shirley's Ray tracing in one weekend. In the True Lambertian Reflection section, when talking about rejection method, he said This distribution scales by the cos^3(ϕ) ...
0
votes
1answer
72 views

Is there a mathematical (as opposed to iterative/SDF) test for ray intersection with a grid of circles?

My actual problem is considerably more complex, but can be solved if there is a cheap way to compute the intersection of a ray with a regular grid of circles. If I had a circle centered at every ...
0
votes
0answers
22 views

raycasting in opentk: size of projection plane / direction of rays

I found my error! The solution was as posted for example here: How to avoid curvature artifact in raytracer? ; just multiply the forward vector with cos(angle) before adding the vectors. i want to ...
0
votes
0answers
65 views

Is it possible that a superior, undiscovered 3D rendering method exists?

As far as I know, the only options we have for true 3D rendering are polygonal rendering, ray-marching and raytracing/casting. Why is that? Surely there must be other ways? Is there some paper ...
0
votes
2answers
131 views

How to avoid curvature artifact in raytracer?

I have a pretty simple raytracer that is rendering some SDFs, but when my camera is close to the object I see curves: I am not entirely sure where they are coming from, as I am using nothing but ...
0
votes
1answer
45 views

What is the attenuation function for a reflected light

In a real-time rendering program, when a light hit a plane and reflected, how to calculate the attenuation(by distance) for the reflected light?
2
votes
2answers
71 views

Examples of anisotropic surfaces

Being faced with a design choice, I have to decide between supporting anisotropic surfaces or not in my ray tracer. Is there any common use case of this feature other than velvet (so that I may be ...
1
vote
1answer
102 views

How to change a RGB value using a radiance value?

I am new to this awesome community, I am currently writing a ray tracer but I hit a problem... Let's say I have a surface(material doesn't matter) of colour [1, 0, 0] in RGB, and the radiance reaching ...
1
vote
0answers
51 views

Shadow Bug when Raytracing Triangles

Spheres with shadows work fine. But when I try to include triangles with shadows, they are shaded incorrectly (i.e completely black): But when I disable shadows Blinn shading on triangles work fine (...
3
votes
0answers
46 views

ray racing (Whitted) bad shadow on far objects (artifact)

situation: I've implemented a Whitted style ray tracing in C. Everything appear to works except the shadow cast by small object on big far objects The problem : red sphere have radius 0.5 orange ...
2
votes
1answer
63 views

How is raytracing performed in anisotropic media?

I wish to determine the path taken by a light ray between two points, $a$ and $b$, through an anisotropic medium. More specifically, this medium has an index of refraction which varies as an ...
0
votes
0answers
27 views

How to calculate MIS weight for indirect light path?

I am trying to add MIS into my render. So, looking into some shadertoy examples. https://www.shadertoy.com/view/MsXfz4 https://www.shadertoy.com/view/4sSXWt Here comes the problem. All of them are ...
0
votes
0answers
23 views

Double sided area light produces much more fireflies than single sided, how to fix it?

I am testing area light with my render. I prefer double sided light, because it produces some glow around the light. But it produces much more fireflies which is annoying. While the single sided light ...
1
vote
1answer
49 views

When sampling direct light, what to do if testing ray been blocked by transparent object?

As the title above. I am trying to sampling direct light and indirect light. But I have many transparent objects in scene, it's very likely to block the testing ray. To my understanding, it's not good ...
0
votes
0answers
64 views

Ray tracing tree

Let's suppose that we have a light source. Which of the following are correct for the tree of recursive ray-tracing (ray tree) that create when we make the colors for each pixel in the screen. Which ...
0
votes
2answers
112 views

Can someone explain why raytracing isn't able to make Global Illumination?

I've watched a few videos about raytracing vs pathtracing, and one thing that consistently pops up is the idea that pathtracing seems to be able to do global illumination, whilst raytracing is not. ...
6
votes
3answers
803 views

Fundamental drawbacks of rasterization over ray tracing

Are there any fundamental drawbacks/limitations of rasterization as compared to ray-tracing? When I search on the internet, I get vague explanations like rasterization does not provide lighting ...
0
votes
0answers
46 views

Raytracing, divide by PDF neutralized the effect of D and G terms, what is the problem?

Following some documents on internet, I divide my ray tracing result by PDF. Then it seem the D and G terms disappeared. Only F term is still visible, it looks like Fresnel only. ...
1
vote
1answer
71 views

Ray tracing Bug with Diffuse material

I am trying to do ray tracing in python (following the tutorial given in Ray Tracing in a weekend). Basically I am shooting rays from eye and the recursively bounce around, each time they hit ...
1
vote
1answer
79 views

Ray tracing geometries with same position, translation and scale

this is my first post on the Computer Graphics Stackexchange forum. Apologies in advance if I am doing something wrong. I have the problem that I have a scene with overlapping geometries. To be more ...
0
votes
0answers
121 views

Ray casting and rasterization 101

Recently I've became an intern in company-name and my internship task is(for now) create rasterization using rays. I'm mostly interested in pure math, so basic ...
3
votes
0answers
145 views

Path tracing : fireflies/hot pixels when directly sampling lights

I am implementing a pathtracer with both indirect and direct light sampling at each intersection (I believe the "direct light sampling" part is also referred to as "next event ...
0
votes
1answer
57 views

What can be the cause of some strange ray shadows artefacts on a perfectly flat surface?

First of all I have to say that I am really new in the world of Computer Graphics. I apologise if some of my questions may appear trivial. I am currently using a non-commercial ray tracing and ...
0
votes
0answers
52 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 ...
0
votes
0answers
38 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 ...
0
votes
1answer
200 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 ...
0
votes
1answer
80 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 ...
0
votes
1answer
50 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 ...
0
votes
1answer
56 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 ...
0
votes
0answers
39 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 ...
0
votes
0answers
49 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 ...
0
votes
1answer
81 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 ...
0
votes
1answer
284 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 ...
0
votes
1answer
37 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 ...
1
vote
1answer
78 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
3
votes
2answers
151 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 ...
1
vote
0answers
43 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 ...
2
votes
0answers
36 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 ...
1
vote
0answers
52 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. ...

1
2 3 4 5
8