Questions tagged [rendering]

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11
votes
0answers
627 views

How correct is rendering in XYZ / linear RGB space?

I have a spectral power distribution (SPD, 5 nm steps) for all light sources in the scene and SPDs for the reflectance of all surfaces under any light / viewer angle in question. I'm going to ...
9
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0answers
210 views

Help with start up bias in Metropolis Light Transport

I'm trying to implement metropolis light transport based on this paper, and I have the basic thing working. I run the algorithm multiple times with different starting points, add the results for each ...
7
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0answers
200 views

Supersampling HDR

I'm encountering some issues supersampling in HDR for an SDR result and was curious what the usual method for doing this is. Notice how pixelated the edge of the white sphere is. Here's how I render ...
6
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0answers
225 views

How is Ambient Occlusion calculated in “Deep Screen Space”?

The paper (http://resources.mpi-inf.mpg.de/DeepScreenSpace/) just says that "The ambient occlusion contribution of a surfel to a pixel [..] as well as the influence radius [..] are computed ...
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 ...
5
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0answers
754 views

Percentage-closer Soft Shadows implementation

I am trying to implement the Percentage-closer Soft Shadows (PCSS) from NVidia inside Unity but I am facing some issue and I don't know where they come from and then, I do not know how to solve them......
4
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0answers
137 views

How is glint rendering done in Ray Tracing?

How is glint rendering done with ray tracing in the photo below? Is it just a simple normal map? I found a paper online that describes the exact same method used in the photo above but I have no ...
4
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0answers
332 views

Incorrect instanced rendering

Previously, to render a bunch of quads, I was simply using a few uniforms (one for a model matrix and another for the texture layer ID). However, I'd rather not have to loop through each quad and set ...
4
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1answer
205 views

How fast should I expect to render the silhouette of a 20k triangle model?

Using VTK 7.0 I have found that rendering a 20k triangle STL model takes approximately 17ms on my Nvidia GTX970. However, I am only interested in the silhouette of this model (like the image below) ...
3
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1answer
83 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 ...
3
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0answers
41 views

2D metaballs with marching squares and linear interpolation

I struggle do understand how linear interpolation works in the marching square rendering algorithm context. I created simple example in GDScript (Godot) of random floating metaballs to demonstrate ...
3
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0answers
92 views

Procedural Generation of 4D Shapes

I'm curious if anyone has any insight into how one might procedurally generate 4D objects, as showcased in Miegakure (or the developer's other game, 4D Toys ). I built a program a while back to do ...
3
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0answers
102 views

Irradiance field approximation with black probes

I'm posting here after some time searching the Internet and reading presentations and papers, to find out the best options to solve the problem I have. I'm implementing irradiance field with ...
3
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0answers
68 views

Why my cosine interpolation of a cube's face doesn't work?

NB please : executable use cases are available at the end of this question. I begin this question by showing you the problems of my program, then I explain how the latter works, and finally I end up ...
3
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0answers
72 views

Strange behaviour in simple software rasterizer

I have a simple test scene setup in a toy software rasterizer. I have a plane facing the +Z axis at the origin and the camera is facing -Z at Z=2. Everything works fine and looks good at that ...
2
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0answers
46 views

Accelerating dose calculation for a radiation therapy planning system

During radiation therapy, appropriate radiation is fired from various positions around the patient. Radiation therapy planning determines the values of the radiation at various positions. This ...
2
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0answers
129 views

Implementing GGX VNDF importance sampling with DXR

I am currently implementing the GGX specular BRDF in a DXR raytracer using the importance sampling method describe by Heitz I am sampling the VNDF with: ...
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 ...
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 ...
2
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0answers
198 views

Not understanding the lighting equation for volumetric cloud rendering

I've been looking The Real-time Volumetric Cloudscapes of Horizon-Zero Dawn, but I'm very confused by a few terms. The presentation mentions "The Henyey-Greenstein phase function" on page 54, ...
2
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0answers
271 views

Rendering of large STL files

I am in the process of creating some software in Java for generating 3D gear geometry and saving it as an STL file. I am looking at a means of drawing the geometry so that the user can view the ...
2
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0answers
581 views

What's the nature of Monte Carlo noise?

Monte Carlo rendering is just a process of sampling and reconstruction to evaluate the rendering equation. Why is it called noise rather than error?
2
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0answers
77 views

Artifacts (numerical errors?) in rasterisation renderer

This might be not laser precision question but this issue appeared a long time ago when first trying to render some scene with 3D models in rasterisation renderer and apply some lighting, ...
2
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0answers
503 views

Calculating intensities of Virtual Point Lights in Instant Radiosity from IES lights

Short introduction I created a function that interpolates the IES luminious intensities (candelas) using Hermite interpolation, so in my code all light sources have $I(\theta, \phi)$ function - but ...
2
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0answers
252 views

Projecting light shapes

I am wondering how professional light visualizer software (like Capture Argo - WYSIWYG - Realizzer - LightConverse) project the lights on the objects (like stage, floor, people), even projecting the ...
1
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0answers
31 views

How to pass only the needed portion of the data calculated in a fragment shader to another fragment shader?

I have an image and I want to draw an arbitrary number of objects on that image. The center coordinates of those objects are calculated inside a fragment shader after series of image processing ...
1
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0answers
52 views

Conditionals and branching in shaders

This is a quite wide subject which implies a lot of topics such as the platform or the compiler, but I think that it could be useful for everyone to know more about this. A common mistake is to think ...
1
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0answers
78 views

Why does my self-written rendering engine make further away objects look larger?

I am writing a very simple rendering engine. I have already made a few tests, but somehow the images it creates look wrong. Objects that are further away from the camera look larger than objects ...
1
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0answers
89 views

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 ...
1
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0answers
106 views

Why does the reflected component in Lambertian path tracing get multiplied by a factor of 2?

I would like to intuitively understand the Path Tracing equation/formula/pseudocode, but I'm not fully getting the last return statement. As per Wikipedia page: <...
1
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0answers
57 views

How to render multiple shaders per mesh

I've tried looking everywhere, but I just don't get it. How is multiple shaders assigned to a mesh if you can only bind a single shader in OpenGL? Assume I have a mesh with a texture shader and now I ...
1
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0answers
25 views

Report standard deviation in Rendering results

I noticed that a common metrics for image quality assessment (Monte Carlo path tracing) is MSE between the generated image and a reference one. My question is: why isn't the standard deviation ever ...
1
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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 ...
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 ...
1
vote
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 ...
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
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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 ...
1
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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 ...
1
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0answers
40 views

Can order-independent transparency sort fragments for a subset of all transparent objects?

I've read Wikipedia's article on the topic, and a tutorial on how it affects MikuMikuDance. I tried to read a patent on "packing the 3D array with a prefix sum scan, or linearizing", but I have no ...
1
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0answers
69 views

Transform a cube in a truncated pyramid

I have to calculate the modeling transformation that transforms a cube of side=1 centered in (0,0,0) in a rectangular truncated pyramid of height=2,sides of basic rectangle equals to 3 and 2, sides of ...
1
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0answers
54 views

Documentation of old versions of gl Matrix library

I'm learning webgl, and I'm using a book that use a old version of gl-Matrix (1.2.4). The newest versions of gl-Matrix aren't backward compatible, thus I'm looking for the documentation of gl-Matrix 1....
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0answers
81 views

How should I understand path-space measurement equation?

I read the corresponding chapter of PBRT-v3, as well as Veach's thesis which introduced BDPT. However I didn't quite understand why we use the measurement equation. It seems that the measurement ...
1
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0answers
88 views

How to eliminate line aliasing in an object made of cubes?

I have a big cube made of smaller cubes, but sometimes, due to the fact that each side of the cube has different colors, I get some ugly colored lines that I would like to get rid off. Any advice is ...
1
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0answers
62 views

Sampling a textureCube using a screen quad

I´m trying to use a screen quad to display the contents of a texture cube (instead of rendering a cube mesh in front of the view). I´m passing to my shader the camera view matrix. The pixel shader ...
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0answers
69 views

Mitsuba Bidirectional Framework

I'm confused by the Mitsuba bidirectional framework for quite a while now, especially by the different eval and connect ...
1
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0answers
71 views

Can one application inject triangles into the graphics pipeline of another application?

If I have two applications that I've written running on a machine, is it possible to have one application inject triangles into the scene of the other application? So effectively, the data for meshes ...
1
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0answers
41 views

What could cause realtime lighting within a viewport to be calculated on the wrong part of the screen?

(I initially posted this in a section that is less suited for the particular issue, oops) I'm having this issue on some of my client's computers (this is for a Unity asset) that I cannot reproduce on ...
1
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0answers
61 views

Specular Highlight Gray When Behind Model

What would cause this grayscaled backside? When my camera is behind my model I see a grayscale specular highlight. However, in front of it is perfectly fine. Here's my shading code. (Software ...
1
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0answers
151 views

Can I voxelize 3D set of points without reconstructing surface first?

I have huge point cloud data I want to render them at interactive frame frate. Process I know is 1.point cloud data 2.triangulate it using delnauy or other triangulation algo 3.surface ...