Search found 46 matches

by papaboo
Tue May 19, 2015 12:05 pm
Forum: General Development
Topic: algorithm choice
Replies: 7
Views: 7221

Re: algorithm choice

OptiX TrBVH is probably the current state-of-the-art for GPUs. What I don't know though is if they build it on top of a 'normal' BVH or an MBVH.

Either way. The optimization of treelet restructuring should be applicable to both, so maybe you can try it out. ;)
by papaboo
Mon May 18, 2015 6:20 am
Forum: General Development
Topic: algorithm choice
Replies: 7
Views: 7221

Re: algorithm choice

The bounding volume hierarchy in one of its many forms. Memory requirements can be determined before construction, so no dynamic memory allocations during construction. Very fast to construct if you choose to use Morton Codes. Can be refitted to dynamic data instead of requiring a complete reconstru...
by papaboo
Mon Mar 09, 2015 7:35 am
Forum: General Development
Topic: Defining roughness
Replies: 6
Views: 5548

Re: Defining roughness

Thanks for the suggestion. I've been looking for a good excuse to read Wenzel's thesis anyway. :D
by papaboo
Fri Mar 06, 2015 6:31 pm
Forum: General Development
Topic: Defining roughness
Replies: 6
Views: 5548

Re: Defining roughness

That is exactly the reason why I would like to be able to define som kind of roughness or 'glossiness' for a surface. Dividing materials into Diffuse and Specular just doesn't cut it in real world scenes. :) Having a roughness or glossiness range would make a lot of approximations simpler and more c...
by papaboo
Fri Mar 06, 2015 1:25 pm
Forum: General Development
Topic: Defining roughness
Replies: 6
Views: 5548

Defining roughness

Hey I was wondering if there was a definition of roughness for glossy/microfacet BRDFs, as this could be useful to a lot of stuff in one of my renderers. Fx An SPPM integrator bases the decision about whether or not to gather photons or continue tracing on the materials roughness. I have seen others...
by papaboo
Mon Feb 23, 2015 2:59 pm
Forum: General Development
Topic: photon mapping + final gather light leaks
Replies: 3
Views: 4900

Re: photon mapping + final gather light leaks

Photon mapping comes with geometric bias and light leaking. There are various ways to reduce it, but you can't remove it without an infinite number of samples and a really really really high precision backbuffer. That being said you can 'postpone' the light leaking until it's is no longer noticeable...
by papaboo
Sat Oct 25, 2014 6:04 pm
Forum: General Development
Topic: How to render soft shadow from directional light
Replies: 4
Views: 4297

Re: How to render soft shadow from directional light

how to render reflected specular high light from delta light sources like directional lights or point lights Please don't go there. :) A point light has zero radius and cannot be sampled from a specular surface. The probability of a specular ray hitting the exact point at which your pointlight lies...
by papaboo
Fri Aug 22, 2014 6:37 am
Forum: General Development
Topic: questions about hair rendering
Replies: 5
Views: 4598

Re: questions about hair rendering

Disclaimer: I haven't read any of the source code or played around with it, so I don't know how well it works. But! I would take a look at Embree. A lot of their 2.x.y relaese notes are concerned with hair, so clearly the guys have invested time in solving this issue. You might need to tweak their s...
by papaboo
Fri Jun 20, 2014 2:57 pm
Forum: General Development
Topic: Energy-Conserving Phong Specular Lobe
Replies: 10
Views: 8517

Re: Energy-Conserving Phong Specular Lobe

Disclaimer: In a rush, so only glanced at the code. Hope this is still helpful. The microfacet model is generally not energy conserving, which I personally see as a feature, not a drawback. The idea is that rays that reflect of your surface and are reflected into the material will bounce around insi...
by papaboo
Fri Mar 07, 2014 12:18 pm
Forum: General Development
Topic: SBVH - support of different kind of primitives
Replies: 3
Views: 3857

Re: SBVH - support of different kind of primitives

You write that it's a GPU engine, so separation of primitives might not be a bad idea. It will decrease tree quality, sure, but it will increase coherence among threads in a warp, which can be a lot more critical. My personal preference for a GPU raytracer with support for multiple primitives (tris,...