Questions tagged [rendering]

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2
votes
1answer
69 views

Mixing HSV Channel

I have a question about the saturation channel. 1.) So far I know, that saturation channel only give intensity to Hue channel, but I do not understand, how saturation channel can be dark and what is ...
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0answers
84 views

Multiple Importance Sampling in Bidirectional Path Tracing

I'm trying to understand the computation of the path density described in the book Physically Based Rendering. They assume that a path $$x=(x_0,\ldots,x_{n-1})=(q_0,\ldots,q_{s-1},p_{t-1},\ldots,p_0)$$...
2
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1answer
77 views

Estimating the position of vertexes in a 3D model

Introduction to my project: We are machine learning scientists and working on a biomedical system for tracking tongue for speech pathology using a technology called EMA (Electromagnetic ...
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0answers
69 views

How to display image from CUDA / What API to port my project to for real-time raytracing?

I started a raytracing project using the python numba library which provides a just-in-time compiler for CUDA kernels. When the scene is rendered my result is a 1920 x 1080 x 3 RGB array in GPU memory....
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0answers
142 views

Which is more important : Texel or Pixel rate? [closed]

I would like to know which is the most important ? More particularly in games or for the display of a desk (ex KDE Plasma, Windows 10 ...) ?
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0answers
26 views

Mitsuba builds targets with scons but throws “undefined symbol” error when trying to render scene

I am trying to implement a custom add-on for Mitsuba, but when I use the Heightfield I have defined in another function call(WaveBrdfAccel) in main.cpp it compiles without any problems but when I try ...
2
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1answer
117 views

light probe (for global illumination) placement techniques?

I'm learning light probes used for dynamic global illumination. I have a question regarding the placement of light probes, as based on most of the pictures I have seen, they seem to be placed ...
0
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0answers
81 views

Software Rendering Display Latency

I've been doing some reading as to how to reduce input delay on modern computing devices. A lot of my understanding from this comes from the VR research paper by Carmack explaining the numerous ...
5
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2answers
173 views

Why do identical polygons not z-fight in OpenGL?

Typically when coplanar or nearly coplanar polygons are rendered in OpenGL, the textures of each polygon mix together in a non-deterministic way. My understanding is that this is caused by the limited ...
1
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1answer
186 views

Tone Mapping in a physically based rendering ray tracer

I'm implementing a pbr ray tracer. Let's say that I'm at the end of the process: for each pixel pi, I accumulated the radiance value in vector pi = (radR, radG, radB). At this point, these values are ...
0
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1answer
152 views

how to update my scene graph?

I am updating my scene graph in response to user input and the network. What is the best way to do this? The updating threads are separate. Some approaches I am thinking about: double buffer. There ...
1
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0answers
71 views

Optimisation of Geometry Pass

I'm trying to optimize a geometry pass for a game using dx11 and deferred rendering. (All test are performed on Nvidia GTX 1060 at fixed clock rate) After profiling with NSight it seems to have very ...
3
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1answer
136 views

How does Next Event Estimation work with transformed lights?

I am relatively new to path tracing, and I am trying to implement next event estimation. I am following the Monte Carlo integral used to compute the direct illumination from an area light: $$\frac{1}{...
2
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1answer
97 views

how many watts are in the SPD of the color white?

Please help. I'm trying to implement a ray tracer, going by the PBRT book and got stuck on an issue that I fail to find the answer to. My scenes are made from objects and light sources. From that, I ...
-1
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1answer
115 views

Unsolved Problems in CQ to this day?

What problems haven't been solved yet when it comes for instance in rendering,deferred rendering, Volumetric lighting, ambient occlusion or in any other interesting area. When i say unsolved problems, ...
1
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1answer
121 views

How to translate the center of an equirectangular projection?

I'm trying to perfectly align two or more equirectangular photos of the same place taken from slightly different positions. Using an example provided by openMVG I managed to get the relative position ...
0
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1answer
81 views

What are the parameters measure the performance of a rendering? [closed]

Let's say I designed a housing model and rendered it using a rendering engine. how can I measure the performance of my rendering?
2
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0answers
102 views

How to model braids?

Many hair simulations render their hair as lines (usually splines). Since hair is a really thin object. if the hair is braided, rather than having thin infinitesimally small cylinders, you have ...
-1
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2answers
153 views

What is a list of common, cheap, real time rendering algorithms?

I am well aware of the existence of Blinn-Phong shading, which is a great tool when you are doing, for example, modelling algorithms and wan't to focus on the model. In this case a full BRDF result, ...
5
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0answers
136 views

How to use Photometric Units with Rendering Equation?

So I was just reading up on how to create more Physically Based Lights and wandered into the realm of photometry. I read the paper "Moving FrostBite to PBR" and in it the author claims he decided to ...
0
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1answer
29 views

Can you generate your own HDRI maps without using photos?

For example, preparing a scene in Maya using standard lights and rendering out a panorama? Could they also be made from scratch in photoshop using 32bit color? Is there a reason why people don’t ...
7
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1answer
1k views

Anisotropic GGX BRDF implementation. How is it related to isotropic GGX BRDF?

Introduction I am implementing anisotropic GGX BRDF and have encountered strange behaviour of my implementation. I thought that if I compare the microfacet distribution function I have with the one ...
3
votes
1answer
197 views

Adding noise to gradient

I found this picture When you zoom in to any part of the image, the background looks a bit noisy/grainy. See pixels around "violent violet" label: I'm trying to understand how to achieve the same ...
5
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2answers
1k views

Multiple Importance Sampling in Path tracer produces Dark Images

So I recently implemented Multiple Importance Sampling in my path tracer which was based on next event estimation. The problem is without MIS I get images like, This is obtained by setting ...
1
vote
1answer
434 views

Texturing an “infinite” plane

I am rendering an infinite plane as described in the following answers: https://stackoverflow.com/questions/12965161/rendering-infinitely-large-plane https://stackoverflow.com/questions/7380250/how-...
2
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1answer
153 views

Rendering Equation for photons carrying flux

I am trying to understand the mathematical/physical foundations of photon mapping better. In the forward photon tracing step it is established, that the rays are carrying portions of total power (...
3
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1answer
394 views

Rendering Fluid Simulations?

I've read about Lagrangian and Eulerian fluid simulations and here's what I take from their methods: Lagrangian - Simulating fluid particles by calculating displacement for each particle Eulerian - ...
2
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1answer
119 views

Computing perspective directly

Assume the screen is axis aligned with origin at 0 and there is absolutely no view transformation. in other words we will simply try to project the model onto the screen plane following perspective. ...
3
votes
1answer
206 views

How to apply wire texture for realistic rendering of embroidery?

I am building an algorithm which takes a bitmap image as input and render the image as an embroidery design. The different steps are : Vectorize the image, I keep only 5 colors (Done) Generate ...
13
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4answers
3k views

For shader math, why should linear RGB keep the gamut of sRGB?

sRGB is often contrasted with "linear RGB." Images are stored on disk and passed to displays in sRGB, which is approximately perceptually uniform in intensity. Shader math is done in linear RGB, ...
0
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0answers
37 views

How to apply SSRT to an existing image with associated depth map?

I have the following image and depth map from a CV paper: I want to know if there is an existing way to apply screen space rendering to a pre-existing image. Before someone yells ate me saying "Why ...
0
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2answers
678 views

Is it possible to emulate Vulkan on a non Vulkan compatible gpu?

I don't think there is much to explain here, since the question is pretty much in the title, but i'll try to explain myself better: My current laptop's gpu does not support Vulkan, so i was wondering ...
2
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1answer
117 views

Z-buffering implementation with small triangles

For research purpose, I have to implement z-buffering algorithm to render 3D face models. But I got a problem that the triangles are too small to be rendered (i.e. there is no pixel covered completely ...
4
votes
2answers
348 views

Difference in pixels between different monitors' sizes

If I have an image of x/y resolution and display it on a monitor, does this mean that between a 15-inch monitor and a 42-inch, the same amount of pixels (x/y) will be displayed, only that each pixel ...
2
votes
1answer
136 views

How do we approximate the integral of the measurement contribution function in Metropolis Light Transport?

In Metropolis Light Transport, we need to approximate the integral of the measurement contribution function. I've read that this can be done using a traditional approach like path tracing. However, ...
4
votes
1answer
376 views

How to visualize and programmatically work with huge point cloud

I have created a quite large point cloud with about 800M RGB points. The exported .ply file is about 12GB large. The commercial software I used to create it can render the cloud very smoothly on my ...
4
votes
1answer
672 views

Non real-time rendering on Unity3D

I made an audio visualizer using Unity3D (you can see it here) but I am not satisfied on the video quality, as the compression destroys the graphics. I recorded the screen during a real-time rendering....
2
votes
1answer
210 views

How can we convert a probability density according to solid angle to a density according to area?

In Chapter 14.5.3 of Physically Based Rendering - From Theory to Implementation (3rd edition), the authors claim that a probability density $p_\omega$ according to solid angle can be converted to a ...
2
votes
1answer
282 views

How does Primary Sample Space Metropolis Light Transport work?

For simplicity, assume we're only dealing with surfaces which have either a Lambertian or perfectly specular material. Morever, assume that the only type of lights are area lights (i.e. surfaces with ...
3
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1answer
352 views

Is there ongoing research on Markov Chain Monte Carlo algorithms (other than Metropolis-Hastings) for use in ray tracing?

Metropolis Light Transport is an application of the Metropolis-Hastings algorithm. Its variants differ only in the used "mutation strategy". Is there ongoing research on other Markov Chain Monte ...
0
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1answer
216 views

Bright artifacts in ray tracer rendering seemingly caused by reflections

I've been working on a new ray tracer recently, but after adding reflections I'm seeing these strange small highlights on my models, particularly on the ear of the silver rabbit below. I've read ...
0
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0answers
112 views

Hard edges appearing in voxel cone tracing (how to remove them?)

I am generating shadows using a voxel pyramid (commonly called voxel cone, although I hate that term). Some of my shadows come as expected, however some are very strange. For example in this image: ...
0
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0answers
171 views

Changing coordinate system from texelFetch to textureLod is breaking the algebra

I have a scene rendered using texelFetch() and I am trying to modify the shader to use textureLod() instead. This is the image generated with texelFetch: When I try to change the shader to use ...
1
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0answers
170 views

Voxel cone tracing artifacts (what causes them and how to solve them)?

I am trying to generate soft shadows using voxel cone tracing. Which gives me the next images: In the first image you can see an artifact of a sequence of horizontal shadows alternating with ...
1
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0answers
379 views

How exactly do soft shadows get generated using a voxel cone tracing rendering technique?

Let's assume we have voxelized a scene, and all of our materials have an opacity level of 1. The reuslt would then look like: If we raytraced the final volume that gets generated after rasterization. ...
1
vote
1answer
201 views

Understanding material .mtl files

I am reading this piece of documentation to understand mtl files So far I am stuck trying to understand the difference between ambient, diffuse and specular reflectivity (Ka, Kd, Ks). If I am ...
2
votes
1answer
899 views

Weird artifacts in my ray tracer

I am getting weird artifacts in my simple ray tracer that I made using the book Ray Tracing in One Weekend by Peter Shirley. Example: (circular pattern on the ground and black tint on the spheres.) ...
1
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0answers
32 views

Proper design of data structure to store wavefront file information?

Currently I have a naive Mesh data structure to store wavefront files. This data has 3 buffers for the vertices, normals and UVs. It works well to the point I can render the sponza scene, despite ...
0
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1answer
648 views

Opengl black screen for a simple translation

i am a beginner to opengl following an online guide, I am trying to make a simple translation to my triangle. The triangle did render correctly when i made a float uniform to translate it, but when i ...
1
vote
0answers
94 views

Tail Recursive Monte Carlo Raytracing

I am writing a raytracer in F# using montecarlo sampling I would like to make my recursive calls tail recursive but I am not sure of this is possible with MC raytracing as one has to evaluate sampled ...