Ray Tracing In General

[nobond]

HI, the question might be vague

Just generally, if we completely ignore the cost, is it true that ray tracing approach is superior than the raster approach ? Or is there anything ray tracing is not good at ?

 

[hoho]

Superior by what metric?

What it's not good at is dynamic scenes where triangles change positions. Simple non-skinned models (a'la quake3-HL1 era) are doable with hierarchies, anything more complex will be a huge hassle.

 

[3dilettante]

The two have been compared and discussed before.
The following thread is the most recent example I've seen:
http://forum.beyond3d.com/showthread.php?t=61632

If cost is thrown out the window and we can provide an unbounded amount of performance and resources, the approaches aren't so different.

 

[hoho]

If costs are out I'd just let a gazillion photons loose in the scene and simulate actual light instead of faking it with ray tracing

 

[Ethatron]

3D Rasterization – Unifying Rasterization and Ray Casting

 

[rpg.314]

tl;read abstract

Nice theoretical paper. But why would anyone care for primary ray only ray-tracing?

 

[Dade]

You may be interested in reading this thread too: http://igad2.nhtv.nl/ompf2/viewtopic.php?f=3&t=87#p392

P.S. Ompf is a small forum hosting discussion mostly focused on ray-tracing.

 

[jlippo]

Also Ray Tracey's blog is quite nice place to see all sorts of cpu/gpu realtime raytracers.
http://raytracey.blogspot.com/

Brigade seems to have flooded first couple of pages, but there is all kinds of tracers in older pages.

 

[cjo]

Also Ray Tracey's blog is quite nice place to see all sorts of cpu/gpu realtime raytracers.
http://raytracey.blogspot.com/

Brigade seems to have flooded first couple of pages, but there is all kinds of tracers in older pages.

I think he works for a company collaborating with the brigade authors now.

 

[Davros]

I was hoping Ray Tracey would be his real name

 

[Simon F]

If costs are out I'd just let a gazillion photons loose in the scene and simulate actual light instead of faking it with ray tracing

Why stop there? Some years ago (more 15 I suspect) there was a paper that did rendering by propogating wavefronts!!!!!

 

[MfA]

Raytracing has the same problem it has always had, it is not good at being fast for primary rays and (approximate) shadow rendering for scenes without lots of subpixel polygons... and that's still pretty much what we are doing in real time as far as visibility goes. Once we go down the path of subpixel geometry and non precomputed GI the time will have come for raytracing.

 

[rpg.314]

And the king of subpixel geometry uses.... stichastix rasterization.

 

[nAo]

Raytracing has the same problem it has always had, it is not good at being fast for primary rays and (approximate) shadow rendering for scenes without lots of subpixel polygons... and that's still pretty much what we are doing in real time as far as visibility goes. Once we go down the path of subpixel geometry and non precomputed GI the time will have come for raytracing.

A rasterizer optimized for very small primitives looks a lot like a ray tracer minus walking over the acceleration structure (for instance one could design a rasterizer that handles 2 small primitives that share an edge). Even in that case I am not sure I'd go with a ray tracer for primary rays anyway (certainly not if the model is dynamically tessellated to sub-pixel triangles).

 

[rpg.314]

There has been a lot of work on micro triangle rendering in recent times. None of it ray tracing related.

Reyes has been doing stochastic rasterization with sub pixel triangles for 25 years now.