Questions tagged [volumetric]

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4 votes
1 answer
402 views

How to calculate volume of any given 3D mesh

Given 3D mesh with a closed surface. (solid object without hole). I'm looking for an algorithm to calculate its volume. There are several ideas, Such as Voxelized and count voxels Point cloud and ...
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1 vote
1 answer
36 views

(Lorenz-)Mie phase function instead of Henyey-Greenstein?

Is it practical to implement the Lorenz-Mie(LM) phase function in a renderer ? $p(\cos\theta)=\frac{|S_1(\theta)|^2+|S_2(\theta)|^2}{4\pi\sum_{n=1}^\infty (2n+1)(|a_n|^2+|b_n|^2)}$ I'll spare you the ...
1 vote
0 answers
23 views

Distance to arbitrary set of line segments acceleration structure?

Background: I'm trying to render lightning within a volumetrically rendered cloud. I'm currently using a series of line-segments to represent lightning. At first I used a distance field rendered into ...
  • 280
0 votes
1 answer
108 views

Trying to understand how to render a volumetric point light

My goal is to render a volumetric point light as explained in this book's chapter 10: FGED Rendering The book explains the math pretty well, but I'm not sure I understand what is the required setup ...
  • 289
3 votes
1 answer
88 views

Why does UV tiling affect performance in volumetric ray marching?

I am building a volumetric ray marching shader in HLSL in Unreal Engine, based on Ryan Brucks’ work: https://shaderbits.com/blog/creating-volumetric-ray-marcher I am trying to add some additional ...
2 votes
1 answer
76 views

Techniques to implement a glow that encompasses a volume

I have an old renderer from years ago written with OpenGL immediate mode. I've decided to learn Vulkan and I'm converting my old project as a way to learn the new concepts. One of the things my old ...
  • 123
0 votes
0 answers
97 views

Euclideon Unlimited Details Voxel Engine Architecture

As I understand Euclideon haven't just rendered voxels for these infamous demos, since the amount of geometry is still too large for the 2010 PC with software raytracer and the model taking whole HDD ...
  • 103
1 vote
0 answers
155 views

Isosurface with cracks between LODs

I have an octree containing different LODs of an isosurface that was extracted using Marching Cubes. Neighbouring chunks show surfaces that do not line up if they have different LOD. See image below. ...
  • 260
0 votes
2 answers
279 views

How to handle different data types (uint8, uint16, float) in Volume Datasets?

So I've written a personal volume renderer which currently visualizes datasets (CT-Scans mostly) that have a .raw extension and the values are in the range ...
0 votes
1 answer
164 views

Deep Learning for 3D Point Clouds, volume detection and meshing

I'm working (as a Post-doc) on an archaeological excavation point cloud dataset with over 2.5 Billion points. This points come from a trench, a cuboid 10 x 10 x 3 m. Each point cloud is a layer, the ...
3 votes
1 answer
79 views

Adding two fogs

When calculating fog along the ray we have two main part- transmittance and scattering. What happens when we have two different fogs? With different extinction and color? Both extinction and color ...
  • 566
3 votes
0 answers
780 views

Can I use Path tracing together with Ray Marching?

So I'm trying to render participating media like clouds/sky/fog (Sky is the first step) etc. I had already implemented a normal pathtracer and I was thinking of extending it. But I heard terms like ...
1 vote
1 answer
80 views

Local Coordinates of Deformed Lattice

I'm making a lattice based volume FFD and I'm having trouble with gaps in my data resulting from doing a typical deformer. I think I need to go through the voxels in the deformed lattice and then find ...
-1 votes
1 answer
141 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 vote
2 answers
280 views

Ghosting in volumetric lighting

Does anyone know any method to remove ghosting in volumetric lighting? When light move it leaves trail behind, i would like to remove it. Volumetrics are Bart Wronski style (in frustum) with ...
  • 566
0 votes
1 answer
115 views

Choosing corner values for trilinear interpolation

I'm caching distances for SDF functions in volume textures for faster rendering, and I'd like to use trilinear interpolation for smoother edges. I know that I'll need distance values at each corner; ...
1 vote
0 answers
46 views

Has anybody extended parametric surfaces to volume density representations usefully?

Current mainstream technology does not really model the density functions very well. Yeah, we can use volumetric grids, FEM, voxel representations and particle clouds that define densities. But these ...
  • 8,189
0 votes
1 answer
321 views

How to compute volume of intersection of non-axis-aligned cuboids in 3D?

Given two cuboids in 3D space (8 vertex coordinates each) that are arbitrarily oriented, how can we find the volume of overlap between them in the fastest manner?
  • 101
1 vote
0 answers
273 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, ...
  • 280
4 votes
1 answer
496 views

Experimental real-time shadowing techniques?

The three most popular shadowing techniques for real time applications are: Shadow maps Advantages: Fast "Simple" Disadvantages: Numerical limitations lead to artifacts and jaggy shadows You ...
  • 1,449
5 votes
1 answer
425 views

How to do heterogeneous volume absorption using path tracing?

I want to do volume rendering using path tracing with a absorption only model. And my data is in a 3D grid, which is turned into a voxel medium in my renderer. However, I can't seem to be correct ...
  • 293
2 votes
1 answer
340 views

Volumetric raycasting with transparent rasterized geometry

I have an idea of how to render opaque rasterized geometry alongside raycast volumes: Render rasterized geometry to a depth map and also a render target When raycasting, check position against the ...
  • 121
6 votes
1 answer
1k views

Volume Rendering (Path Tracing & Real-Time)

I have a few doubts and questions regarding volume rendering, I was hoping someone here could help me understand. I commonly hear the terms 'Ray-Marching' & 'Volume Rendering' being used together ...
  • 2,433
3 votes
2 answers
409 views

Frustum aligned volume integration - aliasing issue - temporal reprojection

Raw volume raymarching especially aligned with frustum seem to produce a lot of aliasing/banding on edges of shadow map. Especially when fragment pos is far because step length is then getting bigger. ...
  • 2,047
5 votes
1 answer
621 views

mapping 3d texture on view frustum (or part of it)

I'm implementing volumetric fog in my OpenGL renderer. First I inject color into 3D texture using compute shader, atomic operations and shadow map visibility check. The information I use to compute ...
  • 2,047
6 votes
1 answer
224 views

Volume Rendering in simple words

I am looking for a explanation about volume rendering in simple words, a step by step kind of, like ray tracing: for every pixel in the screen plane, trace a ray starting from the eye point to ...
11 votes
3 answers
6k views

How are volumetric effects handled in raytracing?

How are volumetric effects such as smoke, fog, or clouds rendered by a raytracer? Unlike solid objects, these don't have a well-defined surface to compute an intersection with.
  • 1,462
11 votes
1 answer
364 views

Volumetric rendering fundamental concepts and terminology

Literature on rendering volumetric materials and effects tends to use a lot of mathematical physics terminology. Let's say that I have a decent handle on the concepts involved in surface rendering. ...