Maxwell Render

Hi,

I'm making a SSS skin head texture, its working pretty nicely. The new SSS is looking pretty good.
I have a problem though when i try and put a glass space helmet on my character. The SSS seems to stop working. Is this a current limitation with SSS?
I've tried paying with the setting in the transparent material, but it doesn't have any effect. - Saying that there might be the tiniest bit of SSS effect coming through when i put all the transparency settings to the most transparent and I ramp my back light up to 10,000% but its difficult to tell, as it still looks like noise after a couple of hours.

Texture wise i've tried with the preset glass - both versions - then i've tried putting the settings to what i imagine is there most transparent settings (still not 100% on the meanings!) so I've tried putting the transmittence to 100% white - i know your not meant to do this, but just testing it. And I've tried putting the Attenuation to 999 meters. I've tried with The ND at 1 as well as 1.5. Nothing seems to make a difference.

I've attached some examples but its difficult to see in most renders.

Here is the head with SSS - no helmet:




Then with the helmet on:






And here are some tests I did with a simple cube object with the same SSS texture on:

With no glass:



With a thin rim of glass - (I've double checked all the normals):



With a solid glass Sphere:



Again you can see something in these, but its not just the rendertimes - which would be unusable, also the light is bosted to 10,000% to get it to show anything.


If I move the emitter inside the sphere (not solid but rim again) it works again - fairly obviously i guess:




And finally I tried it with a rectangle inbetween the light and the object with the same results and a one poly thin plane inbetween, still with the same results:




Is there anything i'm missing? There aren't any kind of bounce settings are there? It seems like is the kind of thing that should be straightforward in Maxwell?

I hope that all makes some sense to someone, its confusing the hell out of me! Any help much appreciated.

Cheers,

Rory.

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Once Were Farmers
Digital Image & Animation

i've been doing tests with this SSS in glass for some Bloody Mary drinks I have to render. I've found that it seems to work, it just takes a REALLLLLY long time for noise to clear....and actually, i'm not sure if it will ever clear. Eveytime i've done it, i've had to do ALOT of blurring and noise reduction in photoshop.

The results you're seeing where it's nearly all black with a few light spots is how my renders always look at first. as I let them render the black areas fill in...it basically gets brighter the longer it renders.

To me it doesn't seem to work as it should, because I do have to ramp up the light intensity ALOT to get the bloody mary to look the same in the the glass as it does out of the glass.

those are my results at least. Anybody else?

indeed, it just doesn't seem to work as it suggests in the manual that the attenuation is the distance at which half the energy is absorbed. I can set the attenuation distance as high as it will go (which seems to be 999m) and the transmittance value at 255 and it still seems to absorb 99.99 percent of the lights energy - for Subsurface anyway. It does still light the object on the outside.

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Once Were Farmers
Digital Image & Animation

I've just realized after you mentioned the Bloody Mary tests that There is a picture of Orange juice looking very nice in a glass. Someone must have it working - unless they just left it rendering across 100 computers for a couple of weeks to get that image.

This one:

http://www.maxwellrender.com/img/galler ... nostou.jpg

Thomas, how did you get this to work?

Rory.

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Once Were Farmers
Digital Image & Animation

will AGS work for the scene, or do you need/want refraction?

Cool character OWF i like the style of your spaceinvader.

About the issue with glass ontop of sss, i think that's a bit of a problem since it's like cake-on-cake. It's so many lightbounces to calculate that you will have a infinite amount of heavy noise that needs to be cleaned and it will probably require something like an eternity to clear with Maxwell.

But then again, considering what kinda magic trick ThomasAn pulled off with his juiceglass. I don't know.. he must know how and what to do.

/ Max

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http://maximus3d.blogspot.com/
http://magnus3d.cgsociety.org/gallery/
http://www.flickr.com/photos/magnus3dphoto/

Refraction would definitely be good, but i'd probably sacrifice it to get the SSS working. I've just tried the AGS glass and it's basically the same. A tiny amount of energy getting through and extremely noisy.
Its not just that I'd need to wait an age for it to render also I'd need to crank the lights so crazily high that it wouldn't work with the rest of the scene.

I wonder if the orange juice render works because the juice is intersecting with the Glass?

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Once Were Farmers
Digital Image & Animation

i'm running a test right now--three concentric spheres, outside is glass, next one is "air" (slightly smaller than the outer), and the inner-most is "butter" sss preset (smallest sphere). All spheres are the geosphere primitive that ships with MWR.

first render: all three spheres = sss is black after S.L.12
second render: only "air" and butter spheres = sss is black after S.L.12
third render: "butter" only = typical sss result from this preset

images to follow

here's what i got before I stopped the render (SL 18, I think) and did the rest in photoshop.

Luckily, this has no real detail in it, so in the end I was able to creatively blur the hell out of it to get the noise out. So i was able to get it to work to some extent, sorta.

this is a tough situation: the sss element is lit entirely by caustics (for the helmet scheme). the only real solution is time and horsepower

Have you tried using AGS instead of glass? No caustics = faster render.

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Brian Looney
Maxwell + RealFlow
http://lunatic-studio.com/
Help! I'm dispersing into a haze of probability!

Behind a thin glass shell (bulb) means anything inside is lit by caustics-only. This kind of setup will not easily clear up nor practically useful. So, I'd also suggest compensating that using AGS. SSS alone already requires lots of bounces so it's a very hard setup for rendering. Thomas' glass is rendered using his own technique so it's an SSS volume embedded inside a glass volume. Not exactly the same thing with trapping the SSS object behind a glass shell. It took a lot of time rendering it, too. But a glass shell won't have that chance. At least for now.

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Next Limit Team

the best bet is to take two passes at it....

1st pass is without the glass.....

the second can use the projected image of the skin for the head and render the glass only....use the others as ghost objects....seen in render calc but not rendered....

then composite the two....

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i regret that i have but one proc to give for my maxwell

Cheers for the reply's. I have tried the AGS Glass, it is maybe a little faster but not that much difference to be honest.

I thought I might have to go down a compositing two renders together route, just not sure how I'll go about it in Maxwell. I'm used to doing it in C4D and Shake, but never tried in Maxwell.

I'll try the Ghost option, see if I can make that work. But i guess I'd need to put the Head on a plane inside the helmet, which wont have the correct reflections? Is there anyway to bake a rendering on the model of the head? - The whole texture? I guess I could render out just the head and then frontal project it back onto the model. - Right just thinking out loud now... I try some of that and post an image of any decent results I get.

Cheers,

Rory.

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Once Were Farmers
Digital Image & Animation

like I said a few posts back; I ran some tests and I've run into something interesting: geometry that is effectively a clip map behaves similar to glass (causing an object inside to be lit entirely by caustics).

example:

two concentric spheres, outer one set to 100%transparent with nd=1.00 (essentially a clipmap), inner sphere is butter sss preset




here is the render with the outer sphere hidden:



maybe this is why AGS doesn't work like one would think??