Chaos Corona Forum

General Category => Gallery => Topic started by: damjan on 2012-11-08, 00:44:04

Title: caustic experiments with photographic lenses
Post by: damjan on 2012-11-08, 00:44:04

First - i have to say - i just downloaded corona some hours ago, and i have to say this is the most promising renderer i saw in many years! (and i saw a lot)
I dug out some old maxwell scene i did for a presentation a while back (explaining the working principle of a camera lens)

The images you see here are not so easy to grasp - its basically a rebuild of an old cook triplet camera
I got all the info from google patents - ior, lens radius etc.

the results are perfect compared to vray and maxwell - and extremely fast!
maxwell was also good, but 10 times slower.. vray didnt reproduce anything close to this (even with gpu)

20 minutes each, and one i had to flip - like in a real camera ;)
(no postprod - straight from the engine)

Title: Re: caustic experiments with photographic lenses
Post by: Ondra on 2012-11-08, 01:12:33

Wow, that is awesome!

We tried something similar with Rawalanche some time ago, but we've only gotten to single-lens camera: https://www.facebook.com/media/set/?set=a.149696258503558.34042.149376231868894&type=3

Can you post pictures of the entire scene setup (wireframe)? And how did you get the first image? Is the camera looking directly through the lens, or at the projection plane?

Title: Re: caustic experiments with photographic lenses
Post by: Ondra on 2012-11-08, 01:35:51

And one last thing, would you be willing to share the scene? I would love to use it for testing new GI algorithms ;)

Title: Re: caustic experiments with photographic lenses
Post by: damjan on 2012-11-08, 01:39:20

camera is looking at the projection plane
i did at the time comparisons between spherical/aspherical and cooke triplet
attached is a wireframe and an old side from the presentation (its maxwell, and took ages to render)
the problem with aspherical lenses was the function to generate them was, lets say not so hard to get, but once i had the patent papers in front of me, i gave up on it
btw - all the curves were created in rhino and meshed in max - just for precision - this whole setup is rather fragile when it comes to mesh resolution and small errors multiply as the light propagates trough the lenses

Title: Re: caustic experiments with photographic lenses
Post by: Ondra on 2012-11-08, 01:42:47

yes, I tried to model a parabolic lens, but I scratched it, because I would have to program it as primitive into 3dsmax to get good precision :D

Title: Re: caustic experiments with photographic lenses
Post by: damjan on 2012-11-08, 01:43:47

for sure! its just - the scene is a total mess as is went from originally maxwell, to vray, to corona - and the layers are a mess too - you will find other lenses in there as layers (some fancy wide angle - but i lost the patent pdf, so no ior numbers :/

Title: Re: caustic experiments with photographic lenses
Post by: damjan on 2012-11-08, 01:56:21

and just in case:
http://www.google.com/patents?id=fqxnAAAAEBAJ&zoom=4&dq=3359057&pg=PA1#v=onepage&q&f=false (http://www.google.com/patents?id=fqxnAAAAEBAJ&zoom=4&dq=3359057&pg=PA1#v=onepage&q&f=false)
here is the cooke triplet data

and here the wide angle one:
http://www.google.com/patents?id=NY87AAAAEBAJ&zoom=4&dq=3731989&pg=PA1#v=onepage&q=3731989&f=false (http://www.google.com/patents?id=NY87AAAAEBAJ&zoom=4&dq=3731989&pg=PA1#v=onepage&q=3731989&f=false)
there are 2 different ones, i dont remember which one i built - there are good indicators in the pdf, but i scaled the whole thing in max - so you would have to check relative numbers to find the right ior set..

Title: Re: caustic experiments with photographic lenses
Post by: maru on 2012-11-08, 16:05:43

Corona obscura! :O

This is amazing! I remember doing some tests like casting caustics of an object through a little lens in Brazil and it worked, but never something so complex! Great to see. I wonder how Vray's path tracing would handle such scene...

Title: Re: caustic experiments with photographic lenses
Post by: Chakib on 2012-11-08, 16:15:05

Amazing test ! keep going man

Title: Re: caustic experiments with photographic lenses
Post by: Ondra on 2012-11-08, 16:21:26

Quote from: maru on 2012-11-08, 16:05:43

Corona obscura! :O

This is more advanced stuff, camera obscura was done earlier ;): https://www.facebook.com/photo.php?fbid=149696281836889&set=a.149696258503558.34042.149376231868894&type=3&src=https%3A%2F%2Ffbcdn-sphotos-b-a.akamaihd.net%2Fhphotos-ak-ash4%2F257289_149696281836889_1399208903_o.jpg&smallsrc=https%3A%2F%2Ffbcdn-sphotos-b-a.akamaihd.net%2Fhphotos-ak-ash4%2F296595_149696281836889_1399208903_n.jpg&size=1280%2C720

Title: Re: caustic experiments with photographic lenses
Post by: maru on 2012-11-08, 16:48:09

Yeah, I know, I came here via facebook. But Corona Obscura sounds cool. ;)

Title: Re: caustic experiments with photographic lenses
Post by: Ondra on 2012-11-08, 19:17:00

oh, corona obscura, not camera obscura ;) Sorry, I need some sleep ;)

Title: Re: caustic experiments with photographic lenses
Post by: racoonart on 2012-11-08, 20:07:44

impressive O_o
I wouldn't even have tried such a thing :D Is there some "practical use" or is it just a proof of coronas awesomeness ;)

Title: Re: caustic experiments with photographic lenses
Post by: Javadevil on 2012-11-09, 02:20:49

Cool, I like it :)

Title: Re: caustic experiments with photographic lenses
Post by: damjan on 2012-11-09, 02:26:59

had some "practical use" ;)
a while ago we had to do a short lecture on camera lenses - specifically why there are so many in one lens, and not just one..
after some research i had the idea why not try to render it (with maxwell at the time)
since then this became a good stress test for render engines to me.
and corona did the best job so far
lens flares i will try next ;)