Mental Ray Volume Caustics

[JeffPatton]

*bump*

[JeffPatton]

Well,
Incase others have tried to recreate this and were struggling like me, I have made some headway. Now I need to figure out how to extend the volume effect.

http://www.pixelperfectgraphics.biz/cg_files/volume1.jpg

[Damm]

nice work :).. i'll look into it

Edit: oh my.. it's taking ages to render. I hope i do get some volume caustics :hmm:

hmm i didn't get anything :sad:..

http://shadow.krabbit.com/abbe_personal/v_caustics.jpg

gonna keep trying tho

[Damm]

any more progress for you folical9??

[JeffPatton]

No, I haven't made any further progress. But I'm attaching my scene here and if you (or others) want to expand on it, please feel free to do so.

Download Volume Caustic Test (http://www.pixelperfectgraphics.biz/cg_files/volume-test.zip)

[Damm]

thnx i'll see what i can do with it :)

[tx413]

I can't get any vol caustics either. I've compared mine with folical9's MAX file and can't seem to find what's wrong.

I get this:
http://redwar.us/images/volcausticstest.jpg

If I boost the energy output it'll do this:
http://redwar.us/images/volcausticstest-2.jpg
... but still no vol caustics.

I played around with the one folical9 posted and it's funny how the outer volume box doesn't work correctly unless you use a boolean. The inner one can be just a plain box with normals pointing inward, but the outer one has to be a boolean.

Also, folical9, you can boost your render time by turning caustics off for the omni, or even just turning the omni off altogether. It really doesn't add much.

[JeffPatton]

Oops, did I have that omni generating caustics? Didnt mean to.

I found the effect to work better when I enabled auto-volume from the render dialog box.

[TOMMY 3D FREAK]

Hi guy's,

I've been struggling with this problem also. I've tried to port the maya tut to max, but haven't gotten far yet.

I'll let you know if it works!

[TOMMY 3D FREAK]

Thanks a lot folical9!

Great scene.

[TOMMY 3D FREAK]

Ok,

Here's what I've come up with:

It toook about 15 min to render:

http://www.spectrum-animation.com/junk/ddd.jpg

[JeffPatton]

Cool, what did you adjust to make the volume effect longer? Or did it do it on it's own because the object is not the sphere?

[Damm]

ah.. so it's the "Map #55" that you've assigned to the "box"

i thougt it was the "wall" shader :)..

no wonder nothing happened when i modified it..

[Damm]

Anyhow, the only thing i managed to change within the shadero for the box was the color.

But i did get this when i lowered the extinction on the photon volume on the photon catcher shader

http://shadow.krabbit.com/abbe_personal/v_caustics2.jpg

I can't say that it's any longer. But it's thinner alright :)

[TOMMY 3D FREAK]

I also want to note that you must realize to use the right ior, If you use an ior that is to high, the rays will spread out very fast, which will makes the effect less visible. So try reducing the ior...

:beer:

[PENdzel]

ups :) sorry folical9 - i dont see this thread ... :)

[JeffPatton]

No problem man. I figured you hadn't seen this one floating around.

[60WE]

Hi all, here is my tests:

http://www.freewebs.com/perotinus/volume/volume%20scattering.htm

you are welcome to download my max scene, anyway to control how far the rays have to go you must tweak the decay in MR lights parameters. The default omni light works fine and you have to change just some parameters from the original tutorial regarding especially the outer box (parti volume).

BEST REGADS AND HAVE A GREAT NEW YEAR!

p.s.: I want to thanks folical9 and others members about the thread on shaders (great research)!

[randy_clark]

Can someone please explain to me how Map #55 is used in this scene? It doesn't appear to be used by any material or anything else. Abbegon says it's applied to "the 'box'," but you can't assign a standalone map to an object.

Nevertheless, I see that removing the map kills the effect.

Is there a trick here I'm missing?

Thanks for your help,

-R

[JeffPatton]

Randy, I used it as a camera shader (rendering rollout). I will have to get my head back into that scene (been a while) if you need more details?

Jeff

[randy_clark]

Jeff,

I realized it was a camera shader about 10 minutes after posting that last message. But what I still don't understand is why the scene should need a volume shader for both the camera AND the box. That doesn't seem to make sense (but then, neither does most of the mental images documentation :) ).

Any ideas would be greatly appreciated. Thanks to all on this thread for your help.

-Randy Clark
Discreet

[JeffPatton]

Well, as it turns out, you can delete that "outter" box. It was there because that was one of the steps in the maya tutorial that I was trying to recreate. We don't need that step. Sorry for the confusion. :surprised

Jeff

[TOMMY 3D FREAK]

Hi guy's,

I've been studying this subject also and i've come to the conclusion that you need the following.

I found out a way 2 make the volume caustics lightning fast.

What you need is two planes, a sphere, and a spotlight.

As far as materials are concerned: one partivolume shader for the camera, and one partivolumephoton for the sphere.

I'll post the scene whe I get home 2 night.

I'm also in the process of making a MAX tutorial for it.

One last tip! SCALE MATTERS!!!! When you try to achieve volume caustics remember to set the worldunits properly. And try to model things in real scale. This can dramatically influence rendertime!!!!!



That's it for now.

Greets,

Tommy 3d freak

[_XenO_]

hey pplz
heres some recent tweaks of some of the files posted earlier

http://members.iinet.net.au/~catfiiish/88888.jpg

the beams arent like the sphere example (long and thin) and i havent added the blue glow with photoshop ;)

would like the get the beams to be more pronounced ....still tweakin lol

_Xeno_

[3Drawer]

Hm... I wanted to make this reflec. volumecaustics.....

http://www.motiondesign.biz/items/vol_2_large.jpg

But all I get was this:
http://img.photobucket.com/albums/v88/3Drawer/3d%20images/reflec_volume_ca.jpg






could anybody help me with it?

Thx

anyway....in FinalRender is 100 times easier that in MentalRay. The MR VolumeCaustics are also looking unrealistic. U see it on the first pic.There are volumecaustics but NO fog!

cu!

3Drawer

[3Drawer]

no answers? :cry: :hmm:

[kassinopious]

sorry mate, ive spent many an hour trying to achieve this caustic effect and im sure that im not alone... i found this by ZeBoxx on the slutterfish forums, [edit] he stated that:

1. They were rendered using Brazil r/s, which allowed it to do very crisp hdr versions.
2. They were not generated using Brazil r/s or other SplutterFish utilities. (Speculation on whether this will be in future Brazil r/s versions is therefore moot. Sorry folks.)
3. There are currently no plans to make this public that I'm aware of.
4. Rendertimes are through the ceiling, but not through the roof http://forums.splutterfish.com/images/smiles/icon_smile.gif Think hours for the originals at 1280x1024 using a single P1.6-M
5. Yes, it is a volumetric effect. Specifically it is a 'receiving media'. Which in Brazil r/s (and most renderers, I think) can be made participating media to some extent, but boy would that be sloooooow http://forums.splutterfish.com/images/smiles/icon_smile.gifhttp://forums.splutterfish.com//files/beamy_stuff.jpg

maybe one day he'll spill the beans, untill then i guess we just have to keep trying and guessing

-Kass

[ZeBoxx]

Hi, hello,

Although I can't spill the beans, I will say that :
- It has in the mean time been sped up about 20-fold for caustics only
- The receiving media version is not photons based
- It's SplutterFish, with a 'p'. Without the 'p', the name takes on a whole different meaning ;)

Nice render from mental ray in maya, though - I'll have to try that sometime provided I get a new version

The lamp post is a reflection variant, by the way. I was trying to mimic a light created by one of our clients, which can be seen in our gallery. The idea was to get an even distribution - but my math failed me a little ;)

[JeffPatton]

- It's SplutterFish, with a 'p'. Without the 'p', the name takes on a whole different meaning ;)

LOL, I didn't even notice that one. Classic.

[3Drawer]

Wow that caustics are amazing... but the didn´t help me with my problem:sad:.

And hehe S(p)lutterfish....:bounce: :applause:

cu!

3Drawer

[kassinopious]

- It's SplutterFish, with a 'p'. Without the 'p', the name takes on a whole different meaning ;)

ROFL thats a good one, i'm gona leave it in there just for comedy value :), zeboxx can you go as far as to say whether the effect can be made having only 3dsmax 6 + brazil 1.2 and no other 3rd party software?

-Kass

[ZeBoxx]

can you go as far as to say whether the effect can be made having only 3dsmax 6 + brazil 1.2 and no other 3rd party software?
Nope :) As stated in that follow-up post. They were rendered with Brazil r/s simply because
- it samples nicer than scanline
- the HDR output is much more flexible
- it's what I use (really!)

[ZeBoxx]

Wow that caustics are amazing... but the didn´t help me with my problem:sad:.
I notice your sig mentions finalRender - as far as I know, it should do volume caustics fairly well ?
Not sure if that's an integrated part of finalRender or just a bundled 'Bunch of Volumes', but either way it should work out.

Alternatives, at least max-side, are mental ray and RayMax (if you have max3/4/5 anyway). The RayMax website is unfortunately decaying (gallery link appears to be gone entirely) - but I distinctly remember it having that glass sphere volume caustic bouncing off of a mirror thing.

[3Drawer]

no I use mentalRay( i know in my sig it´s finalrender). With FR volume c. are no problem but with mentalray the are looking strange...


cu

3Drawer

[Radacci]

hey 3Drawer, turn down the brightness of your light in the scene, it is 50 times brighter then a normal 100W light bulb :) that's why the volume caustic is so bright...i tried out your scene and got it darker, but the comp is disgustingly slow, so i had to delete the omni light to get decent rendertime, but that made the scene to dark...oh well...:)
oh, and for caustic effects, use the cone instead of box in the MR-caustic settings, gives sharper caustics.
Havn't tried it myself yet, but try to increase caustic photon count, and decrease caustic radius....wish i could have 600Gig ram instead of megs....;)

[Radacci]

Oh, and i guess the parti volume for camera is to create fog in the scene, normaly you don't get caustics if there isn't particles in the air to reflect it :)
so the parti volume, makes the camera "participate" in caustic generation, by enabeling non-geometric paricles to reflect the light source, in camera view.
I guess, it should work with adding fog to the scene...

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