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Wrong output while implementing GGX importance sampling

I'm receiving a non-energy conserving output while trying to importance sample the GGX Distributionof the Microfacet model, which is generally 3-4 times bigger than the resulting PDF I'm following this blog post: Sampling microfacet BRDF | Cao…
Row Rebel
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What techniques are used to build ray intersection acceleration structures on the GPU?

What improvements and alternatives have been developed since HLBVH was introduced in the 2010 paper HLBVH: Hierarcihcal LBVH Construction for Real-Time Ray Tracing of Dynamic Geometry by J. Pantaleoni and D. Luebke?
user2500
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Ray tracing: transforming ray to object's local space for intersection test

Im writting a raytracer, for which I want to be able to test intersections with implicit surfaces (in my case spheres). Without applying any transformation it works great, but I would like to upgrade it to test intersections against non-uniform…
Nadir
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What is the basic idea of denoising?

When doing random sampling, you can get noisy results if you don't use enough samples like in the shadows below. I know that if you use high frequency noise (aka blue noise), the noise pattern can be high frequency content only, which can then be…
Alan Wolfe
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How to voxelize geometry using textures and shaders?

I am trying to fetch a given geometry and, through (potentially multiple) render passes, create a 3D texture that stores the color value of said geometry into an associated texel. In other words there is a 3D box that i am trying to color based on…
Makogan
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Creating depth map from a 2-D image?

My question is oriented towards the generation of depth map using any of the state of the art depth sensor. However, each of these method required the presence of an 3-D object in front of the sensor. Is it possible the generate a depth map even if…
Virange
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What is a Gaussian Lobe concerning BRDF and NDF?

I was reading a paper about voxel cone tracing and came across this term. So, what is a Gaussian Lobe or a Lobe in general? I am asking in the context of Computer Graphics, BRDF and NDF.
user1006274
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Modulo vs Scaling vs Capping when performing filters

I'm currently taking a graphics course and we've recently covered cross-correlation with regards to using a filter matrix that is applied to a region of pixels in a sort of continual raster-type scan across a larger input image to produce some…
zoombini
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Euler Angles - Gimbal lock, why non-orthogonal axes

Already asked this question on mathexchange but didn't got any promising answers so posting it here Since I'm from a CG background. I really can't understand how and why gimbal lock occurs using euler angles. First of all let me clear this "I know…
gallickgunner
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Inconsistent shading in pathtraced image

I am currently building a pathtracer, which has support for vertex normals and face normals. There seems to be an issue when it comes to rendering objects with triangles exported from Blender. Regardless of how I calculate the normal, the result…
Oliver Cruickshank
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Classify acceleration structure using surface area heuristic

My professor gave me the following example exam question: Given 4 spheres with diameter = 1. Their centers are located on coordinates (2,4,0), (4,2,0), (4,6,0) and (6,4,0), as seen in the picture below. Three different hierarchies of tightest…
Robin Haveneers
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Is Nvidia's delta color compression supported in CUDA, or with DirectX UAVs?

Nvidia discusses their lossless delta color compression is on its fourth generation in Pascal, and that it transparently saves bandwidth behind the scenes for rendering workloads. AMD has a similar technology, discussed in detail here:…
GroverManheim
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How does opengl fixed function pipeline determine specular lighting with an orthographic projection

I have a scene set up with an orthographic projection with the near / far set from -5000 to 5000. The model view is centered at 0 in the z-axis. I am rendering a sphere centered at z=0 with lighting, and the specular component appears as to be…
default
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Sub-pixel image registration using phase

Currently I'm trying to reproduce the result by the academic papers Sub-pixel Shift Estimation of Image based on the Least Squares Approximation in Phase Region by Fujimoto, Fujisawa and Ikehara (Proceedings of 26th European Signal Processing…
Gregor Isack
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Unexpected results from Mitchell-Netravali

I recently implemented Mitchell-Netravali filtering in my path-tracer with 16x (4x4) temporal anti-aliasing. PBR's demonstration image shows it should give significantly better results than the box filter, but my test pictures barely show any…
Paul Ferris
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