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# Questions tagged [spherical-harmonics]

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### Understanding spherical harmonics code

I am trying to understand the function computeColorFromSH, which is a part of the differentiable gaussian rasterizer used by the paper 3D Gaussian Splatting for Real-Time Radiance Field Rendering. I ...
• 103
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0 answers
16 views

### Different basis from spherical harmonics to represent light?

There's a lot of research being done in 3D shape analysis when it comes to PDE methods. Recently I've been reading quite a bit of literature on this subject and recent trends in this subject propose ...
• 566
2 votes
0 answers
278 views

### Spherical Harmonics for view-dependent effects in research of learned radiance fields (NeRF, 3D Gaussian Splatting)

In research on making the rendering of learned radiance fields (e.g., neural radiance fields) faster, many approaches use Spherical Harmonics (SH) to approximate view-dependent color (e.g. baking SH ...
1 vote
0 answers
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### Questions about caculate the highlight direction from spherical harmonics functions

Recently I‘m working on a Precomputed GI Project I'm trying to use a technique called AHD, Amibent Highlight Direction, rendering my project; I use Unity and my target platform is Android. First: ...
1 vote
0 answers
132 views

### alternative to spherical harmonics to model radiance aproximation, optimized for real-time evaluation

I'm looking for a compact representation of radiance over the hemisphere that is also performant to evaluate in realtime (in a pixel shader). The purpose of it is to compress surface lightfields so ...
0 votes
0 answers
90 views

### Baked anisotropic filtering using spherical harmonics

I want to learn is it good or bad idea. Let's assume video RAM is not a problem. For source texture create a texture of texels: spherical functions. Spherical functions defined by small arrays of ...
3 votes
1 answer
917 views

### Advantages of spherical harmonics over baked vertex lighting?

My question is about spherical harmonic lightning, in the context of computing the coefficients with an expensive GI algorithm and passing them to the vertex shader Another way is to just use an ...
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1 vote
0 answers
66 views

### Lighting ramps compressed to zonal harmonics

Let's say I have a lighting lobe represented as a ndotl ramp texture, how do I compress it into a zonal harmonic?
• 121
6 votes
2 answers
5k views

### Spherical Harmonics Diffuse CubeMap. How to get coefficients?

envmap.pdf | An Efficient Representation for Irradiance Environment Maps Spherical Harmonics and applications in real time graphics I am using Spherical Harmonics to turn reflective(mirror like) cube ...
• 321
2 votes
1 answer
126 views

### Multiplication of SH coefficient sets representing occlusion and color

Currently I got interested in implementation of Precomputed Radiance Transfer. I decided that occlusion representation (which is not trivial to compute) would be precomputed as CPU raytracing and ...
• 2,169
5 votes
1 answer
533 views

### Why is spherical harmonics used in low frequency graphics data instead of a spherical Fourier transform?

I'm curious why spherical harmonics are commonly used in real time graphics instead of a spherical Fourier transform. I get that spherical harmonics are in a sort of frequency space (like FT is) so ...
• 7,801
19 votes
3 answers
14k views

### What are Spherical Harmonics & Light Probes?

What are Spherical Harmonics & Light Probes? How useful are they in computer graphics? What exactly do they do? I've heard the word spherical harmonics & Light Probes everywhere, from siggraph ...
• 2,511
8 votes
1 answer
790 views

### Legendre Polynomial equation in Spherical Harmonics

I recently started to read about spherical harmonics. I have a question about this spherical harmonics basis function equation which is mentioned in this StupidSH article: What are those lm() and Re()...
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