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Hi all,

After a long abstinence from Maxwell (and 3D in general!) I'm back on board, honing my skills with a few fun renders. This particular one is incredibly simple: A glass vase on a block of marble... the vase has two volumes, one with clear glass, the other (inner) volume is made from milk glass.

Up until SL 11, the render looks relatively clean, but then sparkly noise develops and won't go away (I haven't let it render to more than SL 18 thus far, but the noise gradually gets worse so I doubt it will decrease).

There's only one light source (physical sky) in the scene. Any ideas anyone on how to reduce this?

SL 11:


SL 15:


Cheers

- Balt

It's probably sun caustics. Try using hdri lighting. Also, is your material SSS inside of glass?

Bubbaloo wrote:It's probably sun caustics. Try using hdri lighting. Also, is your material SSS inside of glass?

SSS: Yes. That's what the vase consists of, I'd prefer not to fake it...?

I've tried using HDRI but I don't seem to be able to get any shadows when not using physical sky. I only ever use HDRI's for background, reflection and refraction, but not for lighting for that reason.

Cheers

- Balt

Are you using Version 2? Sharp shadows are now possible with hdri environment. Plus SSS works best with hdr illumination. If you are already using V2 and can't get good shadows with hdri, it's probably the quality of the hdri that's to blame. Make sure you use hdri that have been made with many exposures, not just a couple. It makes a big difference. I've also heard from someone here on the forum that you can edit your hdri in PS and increase the intensity of the sun disk to get sharper shadows. Haven't tried it yet, but I don't see why it wouldn't work.

version 2.0.3 here... HDRI's are Dosch highres. Maybe the illumination HDRI needs scaled? I tried up to an intensity factor of 500, never got any shadows. Must be operator error... any hints appreciated!

Cheers

- Balt

I'm talking about increasing the intensity of only the light sources in the hdri inside Photoshop, not the whole image.

In this example I'm using only HDRI to light the scene. Not looking good at all! See my other thread on HDRI questions in this same forum, I think I may not be doing this properly...

The same scene lit with a HDRI with a single white ~15 pixel radius circle. SL 15:

I think the best solution for You is to change renderer.

I'm not techno guru though I would suggest that there is something else going on here and maybe at the interface of the two materials!

Though maybe try saving out your physical sky as HDRI and using this for lighting the scene and see what effect that has directly! You can save out the sky under the environmental tab, use a lower res version for illumination!

If I understand correctly, you have an SSS object enclosed in a glass object. So this means that first the caustics have to be calculated, then those caustics are bounced around inside the SSS object, back out through the glass again before reaching the camera. It may clear up in a year or two depending on your hardware.

I would get rid of the glass object, and try to simulate it within the SSS material (added specular layer). Or do the opposite and keep the glass, and fake the SSS object inside with a texture or hdri emitter.

Do not under any circumstances switch to another render engine!

Hi guys,

thanks a lot for your helpful advice! arkviz must have taken offense to something I wrote... no, I definitely won't change renderer! I live and breathe the Maxwell way of life!

I'll try the physical sky export and will report back. I'll also have a closer look at my model, maybe the surfaces are not interfacing closely enough causing caustics inbetween.

Meanwhile, an ashtray I've modelled yesterday. No HDRI lighting yet on that one, physical sky from left, halogen lamp from above.



Cheers

- Balt

balt wrote:arkviz must have taken offense to something I wrote... no, I definitely won't change renderer! I live and breathe the Maxwell way of life!

It is not offense I use to work always with most effecive renderer. Maxwell was frequently used for my works.

Ok, that makes sense if you're trying to get a job done. I'm still trying to master Maxwell so obviously wouldn't know whether I'm approaching Maxwell limitations or my own (traditionally the latter is the case...)

Cheers

- Balt

Hey Balt-I think that your ashtray scene is looking cool... remember smoking is bad for you though eh .

Good luck with cleaning up that scene.... investigation is always part of the learning curve ...p.s. I don't recall seeing that vase before you posted but have now seen it twice more in two days elsewhere!

caryjames wrote:Hey Balt-I think that your ashtray scene is looking cool... remember smoking is bad for you though eh .

Good luck with cleaning up that scene.... investigation is always part of the learning curve ...p.s. I don't recall seeing that vase before you posted but have now seen it twice more in two days elsewhere!

Really? Its famous mate! An Alvar Aalto Finlandia Vase!