Welcome, Unregistered.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Reply
Old 22-Mar-2012, 20:35   #1
nobond
Junior Member
 
Join Date: May 2006
Posts: 98
Default Ray Tracing In General

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 ?
nobond is offline   Reply With Quote
Old 22-Mar-2012, 21:13   #2
hoho
Senior Member
 
Join Date: Aug 2007
Location: Estonia
Posts: 1,218
Send a message via MSN to hoho Send a message via Skype™ to hoho
Default

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.
hoho is offline   Reply With Quote
Old 22-Mar-2012, 21:19   #3
3dilettante
Regular
 
Join Date: Sep 2003
Location: Well within 3d
Posts: 5,495
Default

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.
__________________
Dreaming of a .065 micron etch-a-sketch.
3dilettante is offline   Reply With Quote
Old 22-Mar-2012, 22:39   #4
hoho
Senior Member
 
Join Date: Aug 2007
Location: Estonia
Posts: 1,218
Send a message via MSN to hoho Send a message via Skype™ to hoho
Default

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
hoho is offline   Reply With Quote
Old 23-Mar-2012, 01:39   #6
rpg.314
Senior Member
 
Join Date: Jul 2008
Location: /
Posts: 4,274
Send a message via Skype™ to rpg.314
Default

tl;read abstract

Nice theoretical paper. But why would anyone care for primary ray only ray-tracing?
rpg.314 is offline   Reply With Quote
Old 23-Mar-2012, 09:42   #7
Dade
Member
 
Join Date: Dec 2009
Posts: 183
Default

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.
Dade is offline   Reply With Quote
Old 23-Mar-2012, 13:11   #8
jlippo
Member
 
Join Date: Oct 2004
Posts: 886
Default

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.

Last edited by jlippo; 23-Mar-2012 at 13:18.
jlippo is offline   Reply With Quote
Old 23-Mar-2012, 14:20   #9
cjo
Member
 
Join Date: Mar 2010
Posts: 145
Default

Quote:
Originally Posted by jlippo View Post
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.
cjo is offline   Reply With Quote
Old 23-Mar-2012, 17:18   #10
Davros
Regular
 
Join Date: Jun 2004
Posts: 11,088
Default

I was hoping Ray Tracey would be his real name
__________________
Guardian of the Bodacious Three Terabytes of Gaming Goodness™
Davros is offline   Reply With Quote
Old 23-Mar-2012, 18:05   #11
Simon F
Tea maker
 
Join Date: Feb 2002
Location: In the Island of Sodor, where the steam trains lie
Posts: 4,448
Default

Quote:
Originally Posted by hoho View Post
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!!!!!
__________________
"Your work is both good and original. Unfortunately the part that is good is not original and the part that is original is not good." -(attributed to) Samuel Johnson

"I invented the term Object-Oriented, and I can tell you I did not have C++ in mind." Alan Kay
Simon F is offline   Reply With Quote
Old 23-Mar-2012, 18:32   #12
MfA
Regular
 
Join Date: Feb 2002
Posts: 5,585
Send a message via ICQ to MfA
Default

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.
__________________
Cinematic is the new streamlined.

Last edited by MfA; 23-Mar-2012 at 18:39.
MfA is offline   Reply With Quote
Old 24-Mar-2012, 01:22   #13
rpg.314
Senior Member
 
Join Date: Jul 2008
Location: /
Posts: 4,274
Send a message via Skype™ to rpg.314
Default

And the king of subpixel geometry uses.... stichastix rasterization.
rpg.314 is offline   Reply With Quote
Old 24-Mar-2012, 16:07   #14
nAo
Nutella Nutellae
 
Join Date: Feb 2002
Location: San Francisco
Posts: 4,323
Default

Quote:
Originally Posted by MfA View Post
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).
__________________
[twitter]
More samples, we need more samples! [Dean Calver]
First they ignore you, then they laugh at you, then they fight you, then you win. [Mahatma Gandhi]
The opinions expressed herein are my own personal opinions and do not represent my employer's view in any way
nAo is offline   Reply With Quote
Old 25-Mar-2012, 01:18   #15
rpg.314
Senior Member
 
Join Date: Jul 2008
Location: /
Posts: 4,274
Send a message via Skype™ to rpg.314
Default

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.
rpg.314 is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 13:25.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.