## Search found 50 matches

Wed Jul 25, 2018 7:59 pm
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 569

### Re: Emissive surfaces and visibility term

@ingenious Thanks, that was helpful! I read Veach's thesis Chapter 8 which explains a lot. The intensity of the emissive objects themselves is uniform (i.e. same intensity in every direction), as you sad. When I just naively evaluate the LTE, cosine terms etc. come into play inside the integral. Whe...
Tue Jul 24, 2018 8:39 am
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 569

### Re: Emissive surfaces and visibility term

all geometric factors relating to the light source--surface area, distance, and cosine term--are accounted for in the probability of a ray hitting the light source "by accident." This explanation makes sense. What confuses me however is that both surface area and distance (squared) are pa...
Sun Jul 22, 2018 9:48 pm
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 569

### Emissive surfaces and visibility term

I'm wondering, in a naive path tracer w/o NEE or MIS, do I have to scale the contribution of an emissive surface by a dot(n, -ray.dir) term? Intuition says yes because light intensity depends on solid angle - lights viewed from a grazing angle appear darker than lights viewed from normal direction. ...
Thu Mar 22, 2018 12:05 pm
Forum: General Development
Topic: DXR
Replies: 6
Views: 2061

### Re: DXR

Here: https://www.youtube.com/watch?v=yaK1e59-oAA it suggests that RT is currently a software feature, but that future GPUs will have fixed-function hardware. ("..the next generation of AMD and Nvidia will have hardware to speed this up.."). This is the most important takeaway IMO.
Mon Dec 04, 2017 10:54 pm
Forum: General Development
Topic: Why is volumetric emission proportional to absorption coefficient?
Replies: 5
Views: 2800

### Re: Why is volumetric emission proportional to absorption coefficient?

I think it is required that emitting particles should not scatter light I'm not quite sure if I understand how you come to this assumption and if I totally understand your question, but I don't see why particles that emit light shouldn't also scatter light. However, the mental model behind radiance...
Tue Nov 28, 2017 9:17 pm
Forum: General Development
Topic: Why is volumetric emission proportional to absorption coefficient?
Replies: 5
Views: 2800

### Re: Why is volumetric emission proportional to absorption coefficient?

I don't quite understand the question: doesn't the first term refer to a particle density at an integration position x that emits radiance L_e in viewing direction w, and that the particle density absorbs radiance by w.r.t. sigma_a(x)? The emitted radiance is not proportional to the absorption, but ...
Wed Jun 21, 2017 1:48 pm
Forum: Tools, Demos & Sources
Topic: Visionaray Ray Tracing Framework
Replies: 11
Views: 22968

### Re: Visionaray Ray Tracing Framework

Here's the (extended) AO results from the SEARIS paper (https://szellmann.github.io), along with a script to run the benchmark. Results for interesting platforms (CPU,GPU) not listed yet are highly welcome!
Thu Mar 16, 2017 10:40 am
Forum: Tools, Demos & Sources
Topic: Visionaray Ray Tracing Framework
Replies: 11
Views: 22968

### Re: Visionaray Ray Tracing Framework

Going to talk about Visionaray at SEARIS (http://www.searis.net), which is a workshop colocated with IEEE VR.

Check out this teaser video: https://youtu.be/bhhwEO4KWII
Fri Jan 20, 2017 9:44 pm
Forum: General Development
Topic: Intersection of ray with quadric surface for hobby ray tracer
Replies: 6
Views: 5077

### Re: Intersection of ray with quadric surface for hobby ray tracer

This here paper btw. uses quadrics to project 3-D ellipsoids to 2-D: https://pdfs.semanticscholar.org/df2e/0 ... b231e6.pdf
Fri Jan 20, 2017 9:10 pm
Forum: General Development
Topic: Intersection of ray with quadric surface for hobby ray tracer
Replies: 6
Views: 5077

### Re: Intersection of ray with quadric surface for hobby ray tracer

Here's an explanation of how to build up the 4x4 matrix for several quadric types: https://www.siggraph.org/education/materials/HyperGraph/raytrace/rtinter4.htm I believe that Glassner's 1980's book "Introduction to Ray Tracing" also has a paragraph on this. There's a ray/quadric implement...