View Full Version : GI & Caustics

04 April 2003, 04:15 AM
Whats the best way to fake caustics and global illumination?


04 April 2003, 04:46 AM
Skylight for GI.

Don't know if it works for V10 though.

04 April 2003, 05:33 AM
Dan was here a while back thinking about bringing it to v10.5. Anyway you can get him to update it? Id buy it in a heart beat! :>

04 April 2003, 04:49 PM
I'll ask him but. . . as you can imagine. . . sales for AM products aren't exactly on an all time high.

04 April 2003, 04:49 PM
Scott Bowers just sent me this from the A:M list:

Hey there J. Griffin,
I posted an example of AM Caustic reflected light using photons, about 6 months ago.
At the time I was using 9.5 and have not done any tests using version 10._ Here is a link to the Image._ and here is a bit of DATA:
The clock is a model I had been goofing with for a few months._ It is 6000 patches and has a decal applied for bump and one for the face._ There is one material applied to the whole model._ The material was the standard hash "gold" which i adjusted the colors a bit._ Nothing fancy at all.........
When I became aware of the photon mapping in hash I decided to "check it out" so I simply took my clock......added a little action to pose it, and dropped it into a DEFAULT Choreography setup._ I did not add any ground, sky, environment maps or anything.....all I wanted was to see if the light would actually bounce off the clock.
I did a few test renders at low settings and decided to crank it all the way up and see what happened._ so I set the number of photons to the max number which I think was 100,000.(not remembering clearly it may have been 1,000,000 but as long as you know it was set as high as Hash would allow)
it took 12.5 hours for a p2 400 to calculate the radiosity and another 8.5 hours to render at 800x 600.......pretty long time for such a simple setup aye?_ Well all i wanted to see if the light bounced and it did....pretty interesing the way it refracted off the bottom part of the clock._ As fun as all that was..... the rendering and compute times were way to high for me, and there is too little control over the effect to make it practical to use.
(err I mean test rendering to get it just right is teetering on insanity imho)
Hope this helps you........

Don't know if that helps you koon69 but it's not exactly what I'm looking for. I need to get realistic precious gems sitting on a glass table... muy complicado! I fear that it may be out of Hash's reach at this point.

04 April 2003, 02:38 AM
After I got home today, I fired-up A:M and rendered these gemstones, using radiosity in V10

I used the default settings (except for intensity). No materials, each gem is controlled by basic surface attributes ( you can find the index of refraction for different minerals online...)

The geometry was imported .DXF files that I also found online.:buttrock:

04 April 2003, 02:58 AM
Not bad for a few minutes worth of work.

The green one up front looks good - the others have those gray facets for some reason. I suppose it would just take some tweaking to make it look great... which I will be able to do soon since my new version of A:M should be here Monday!:D

Oh - where'd you find the DXF files? turbosquid?

04 April 2003, 03:07 AM
the gray is reflected off of the groundplane...

If you had made it to the last "Atlanta Animaniacs" meeting, I gave away a whole bunch of little gems (pun intended) like these... I will email them to you if you like, I found them for free on a site devoted to gem cutting. By the way, Colin is talking about organizing another meeting on the 12th (I think), so maybe I'll see you there.

04 April 2003, 03:27 AM
Sure! email away!

I don't know if I'd be able to make it on the 12th. I'm managing a store now:sad: and I have to work most Saturdays. It sucks, but it pays the bills... which is important since I just bought a house:applause:

Kevin Sanderson
04 April 2003, 03:04 PM
For those not on the list...Fabrice Favé just posted this...

Another small test of global illumination with the photon mapping.

Ground : 85%
Wall : 75%
Armchair: 75%

Resolution 320 x 320
Render time: 6 mn 27s

Thanks to Fabrice!


CGTalk Moderation
01 January 2006, 08:00 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.