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Wegg
10-10-2005, 09:08 AM
Couldn't sleep so I decided to play around a bit. Learn something.

So after a few hours. . . I have started to get a basic understanding of how Caustics work in Messiah. (And in general for that matter.)

http://www.eggprops.com/%7Eeggington/RenderTests/Caustics.jpg

I wanted to try and emulate what I had seen elsewhere. (http://graphics.ucsd.edu/%7Ehenrik/images/caustics.html)

I think I have done a pretty good job. I have Caustics Gather Radius set to .01 and the Caustics Photons at 110000. Any more Photons and things seem to hang up. Would be nice to get it just a little more "crisp" like the examples in the link I posted. I know that more Photons and an even smaller gather radius would probably do it but . . . I guess I just don't have enough ram or something. :-(

Caustics don't work if you have Shading Noise Reduction on. . . (bummer).

Pretty noisy in the clear sphere. Its like AA doesn't work within refracted transparencies or something. (bummer).

And things tend to crash if you try and get fancy with any of the shaders. . . (bummer).

They also don't seem to have the right color. They are all just white where the caustics off the gold ring should be gold. . . No?

But. . . it works! Kind of. I'm happy. :arteest:
AAAron
10-10-2005, 12:51 PM
Very intresting, agree that it feels like the ring should give a gold reflection?
One way to get around the AA transparecy problem would be to render at double res without any AA at all and then do a manual supersampling by scaleing it down.
Layer01
10-10-2005, 01:44 PM
They also don't seem to have the right color. They are all just white where the caustics off the gold ring should be gold. . . No?


you think so? i think the ring one looks like it has a slight yellow colour, its just around the white highlights, its not very strong but i think it is there. Maybe its because the caustic is very blurry and if it were crisper ther'd be less white and the yellow edges would be closer together, thus giving it that gold colour you're looking for?
but i could be wrong and the colour, i'm seeing, might just be an optical illusion caused by the surrounding colours.

(not a messiah render or mine)
http://www.mpi-sb.mpg.de/units/nwg3/ws0304/lcn/projects/Michael/ring.png
Wegg
10-10-2005, 03:25 PM
i'm seeing, might just be an optical illusion caused by the surrounding colours.

Your seeing the light that has bounced off the ring. I have GI on. I had a feeling someone would say that so just before I went to bed I set up another one.

http://www.eggprops.com/%7Eeggington/RenderTests/Caustics2.jpg

This time WAY more rays. And a much smaller gather radius. I don't know why it was locking up before but this time it got through it just fine. But. . . as you can see the blue crystal casts white caustics. But. . . DAMN! Look how crisp my ring's caustic cast is!! I'll bet if I kept tweaking I could nail it.

Nah. I'm done playing. :-)
Wegg
10-11-2005, 12:40 AM
http://www.eggprops.com/%7Eeggington/RenderTests/Caustics3.jpg

I couldn't resist.

Man thats sexy. If anyone asks if Messiah can do Caustics. Tell them "Yes." :thumbsup:
Layer01
10-11-2005, 01:09 AM
hey nice results!

looks MUCH better now that the ring one is tighter and crisper.
Your right though, it is very noticable now that you have the blue crystal and its caustics are white...but i'd put forward that maybe the sphere's caustic is maybe a tad bright, other than that its looking good.
Wegg
10-11-2005, 01:38 AM
but i'd put forward that maybe the sphere's caustic is maybe a tad bright, other than that its looking good.

I don't really have all that much control over how bright the Caustics turn out. I can adjust the strength but. . . this is set to "1" which I guess simulates "real world". What I could do is play more with the refraction so it doesn't produce such a crisp dot and therefore cause it to be less bright but. . . its already taken way too long. I'm happy. NO MORE.
Layer01
10-11-2005, 12:50 PM
no no, dont get me wrong it looks great, i was just offering Constructive critisism :)
the brightness of the sphere's dot isn't that big a deal, i was just being picky lol ;)
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