Page 1 of 1

Getting SSS object to render smooth?!

Posted: Tue May 29, 2012 8:05 pm
by bograt
Hi All,

I'm afraid I can provide an image or scene until tomorrow as I don't have my laptop with me at the moment but I thought I would post now just in case anyone knew what I am talking about.
Basically I have been trying to render a solid object (Lee Perry-Smith's head imported to max as one solid obj - http://www.ir-ltd.net/infinite-3d-head-scan-released) using a solid sss material, It seems to render all the polygon faces with no smoothing.
This happens when using a displacement map, bump map, or just as it is. It may be worth mentioning that when I last tried there was no reflection 0deg or 90deg (both were set to 0 black), this seems like it may be important as when rendering objects with reflection everything seems to be fine.
Does anyone know about this? this happens with single sss as well, does anyone know more about how sss works? do Maxwell sss materials require surface reflection to render smoothing applied by 3ds max or c4d?
I will post more details tomorrow morning when I have the files,
Thanks!

Jules

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 1:17 am
by Bubbaloo
Try recalculating the normals inside Maxwell Studio.

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 11:42 am
by bograt
Here is an example of what I mean: Image
I have literally just started using max so I don't know how to re-calculate normals but I will look up and try this, thanks.
It seemed to me to be a problem in maxwell because it renders out reflections fine.
It seems almost like maxwell is ignoring the surface because there are no surface reflections, I though maxwell maybe calculates sss by the volume of the sss (base mesh), then alters its appearance
using calulations gathered from the phong surface reflections... Im stumped

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 11:45 am
by bograt
By the way, The image is with a gray scale 16 bit displacement map applied as a bump map with 25 bump, the scale of the model is accurate to real world

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 12:47 pm
by eric nixon
What does it look like with a normal material? I dont think those stripes on the forehead are related to sss. But either way If you dont know your host app very well thats probably the cause.

I wouldnt assume it was a bug, but I will say that if you use positive assymetry with high scattering, then you need a heavily subdivided mesh to avoid facetting.

But you need to consider that trying to render a human without much 3D experience, is like trying to run before you can walk...

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 1:31 pm
by bograt
Thanks for your reply eric, I see where you are coming from in terms of running before walking but cinema 4d is my preferred software, for mainly compatibility reasons I am using max which I intend to learn, I know I need to learn this stuff but there is no way I'm going to start from scratch. Here is the same model with the same geometry map only transmittance is disabled and reflections are enabled: Image
I have tried normal maps but the geometry is not even registered when in sss with no surface, I am not suggesting it is a bug, simply that an sss object may require surface reflection to avoid faceting.
The asymmetry is neutral.
Btw I have had alot of 3d experience, but have only recently moved to organic models in max, don't be mislead by what may look like a pathetic attempt to render a person using a red sss material,
I am working on a workaround for the lack of the layered skins system in maxwell, I have had good results so far but have not been able to remove the faceting on the sss so it is something that is bothering me.
Thanks for you comments though

Re: Getting SSS object to render smooth?!

Posted: Wed May 30, 2012 1:43 pm
by bograt
This is my first render and I am testing a concept, no displacement and faceted geometry isn't helping anythingImage

Re: Getting SSS object to render smooth?!

Posted: Thu May 31, 2012 12:59 am
by eric nixon
You misunderstood what bubbaloo said, he knows the max side of things, he meant recalc in maxwell studio. Def looks like a normals issue, that wouldnt show up in your black test render unless you used a bump map.

The integration between maxwell and c4d is superb. I think your learning the wrong app from a maxwell productivity perspective. C4D interface is good for precise quick control over large groups of poly's and its very crash resistant for managing massive scenes, 3Dmax always gets the latest plugins and I envy some of the dynamic destruction stuff they have now, but thats really high-end 3D rigging.. Anyway its all about how you use the software in the end.. blah blah..

Anyways the thing about a skin material is how it looks in different lighting, I couldnt get mine to look good in bright sunlight / bright lights, or any fully lit scene.

Re: Getting SSS object to render smooth?!

Posted: Thu May 31, 2012 11:20 am
by bograt
Thanks for your reply, I will try that.
Your right I think, It is a normals issue. I do see the benefits of C4d but as you said Max has all the plug-ins, my initial reason for looking into max was mental ray but I hope to avoid that nasty software now anyway. I'm not a huge fan of Maxwell studio standalone though...
I have managed to more or less remove the faceting effect by using both greyscale displacement and greyscale bump maps in conjunction on the sss model but I still want to get to the bottom of what is causing it.
I very much agree with you about the different lighting of skin, In fact that is the basis of my tests, I want to set up a system that needs no tweaking... I know the lighting here is very ambient so its not a good example but you can notice subtle colour bleed in various places such as behind the ears, I have been trying extreme lighting scenarios and getting very good results, I may post them at some point but it is a work in progress.
Thanks for your help guys

Jules

Re: Getting SSS object to render smooth?!

Posted: Thu May 31, 2012 1:58 pm
by Bubbaloo
Also, normals problems can be caused by unwelded verts. I've never used that mesh, but I know a lot of scanned models I've downloaded have holes, flipped normals, unwelded verts, etc...

Re: Getting SSS object to render smooth?!

Posted: Thu May 31, 2012 2:40 pm
by tom
Have you tried rendering Studio's geosphere with the same red SSS material under same conditions? I think it can also reveal edges. :idea: