In article <41954bb8$1@news.povray.org>,
 Severi Salminen <sev### [at] NOT_THISsibafi> wrote:

> No, this is not about the next version of POV-Ray..or maybe a little :)
> 
> I was looking at WinOSi homepage (http://www.winosi.onlinehome.de/) and 
> it seems to be a very interesting raytracing program. It is basically a 
> true forward raytracing engine: it shoots rays from light sources to the 
> scene - not the opposite as in many other renderes like POV-Ray, for 
> example. At least looking at the gallery it seems to be able to produce 
> some very realistic looking effects without any "faking" or tricks. 
> There is also no need to tweak tens of different settings to be able to 
> produce the desired output. You just set the scene and let the engine 
> render the image. The image quality gets better all the time as more 
> rays are calculated and it is up to the user to decide when the desired 
> quality has been reached.

It is not a "true forward raytracing engine". Such an engine would 
simply be too slow, requiring huge amounts of time and processing power 
to render simple images. One image was rendered recently with such an 
algorithm. It combined the results of of many computers around the world 
over several months to generate an image with 382 billion photons.
http://www.cpjava.net/soupImages/soup_one.png
http://www.cpjava.net/photonproj.html

WinOSi uses some kind of variant on photon mapping...that is, a forward 
raytracing technique used to modify illumination calculations in a 
traditional reverse raytracer. This appears to do the equivalent of many 
passes of gathering a relatively small number of photons, then 
ray-tracing an image to be combined into the final image.

In any case, this way is very slow, and it is not clear that it is any 
faster than equally accurate rendering using photon mapping...I would 
not expect that to be so, from the description of the algorithm. It 
doesn't appear to do anything that can't be done with photon mapping. I 
think this approach is probably a dead end. There are other techniques 
that give extremely good results with far less rendering time.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/

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