Is there a way to set up something like the miss_fast_skin shader for carrara?

What is the miss_fast_skin shader?

It's a realistic SSS skin shader that comes with Maya.

Oh. OK. I haven't used Maya. I'll guess, using MentalRay's SSS Fast Skin Shader as a compare.
No.

There just aren't nearly enough options or controls with Carrara's SSS to make it work like MR's does, or have that kind of flexibility.
You can't, for instance, use any maps with it, or network it with a shader sub-tree of any kind. It doesn't have multi-layer scattering, or multi-layer Anisotropy. Or any other kinds of controls.

Maybe Carrara 6 will have Maya-like SSS.  Let's hope.

Darn. I don't have maya either, but a friend does. I really like the way it does sss. Maybe version Carrara 6 will be better. I wonder if it's possible to fake the look?

Yeah. I think it would be possible to get pretty close to it.
C5's SSS doesn't have a lot of controls or all the little tweaks; but it renders nicely, if you raytrace it.
I think the biggest difference is that SSS is fairly dependant on lighting, and without the tweaks you have to be more careful about how you are lighting your scene.
And then, flesh isn't monotone or consistent; but you can't vary the scatter colors, or intensity (too much, you can use noise; but not maps), so it doesn't have quite the same sense of 'fleshiness'.

You can work around most of that with map(s) in the Translucency parameter (in the shader stack, not the translucency in the SSS, that is just a slider). You can use maps to vary the translucency that way, and that will do a pretty good job in conjunction with the SSS.
It is much harder to set that up than a fast skin material is, and takes a LOT more time to do it. It also won't work well for every kind of material (there are more things than skin that have SSS qualities).

So I'll add my vote for expanded SSS capabilities in C6. Anisitropy too. But, then everybody has there wishlist, don't they?

I'll have to try that. I just completed modeling , rigging, and texturing a  character using  Silo, hexagon, Carrara, and Photoshop. It takes more time to make your own things, but I like it; there is always something new to learn.

Hi guys.  The misss fast skin shader is actually a Mental Ray shader.  It's available in Maya, 3dsmax, and XSI because they all use Mental Ray as a rendering engine.

The quality that makes it unique to all other sss shaders I've seen in Carrara, Vue, etc.,  is that the Mental Ray fast skin shader uses multiple layers for the subsurface scattering effect, and multiple specular layers, which can all be controlled by maps.  It blends the multiple layers in a soft "overlay" effect, which makes hard shadows and bumps appear more diffused under each layer.  It acts kind of like real skin, which we know has multiple layers as well, and scatters light more deeply as you go down each layer.

@luvver_3d:
I'm sure I just read your post in the Poser Forum where you quoted my opinion on 3ds Max 9's MR renderer vs. C5's renderer, and then replied that there aren't any advantages between one raytracer and the next.
Since "a raytrace is a raytracer."; how could anything assosciated with MR, then, have any qualities or advantages that are any different than 'any other raytracer'?
Every tool has it's advantages and disadvatages, is my opinion. I don't view it as somehow sacreligious to discuss them; and I use whatever tool I have that is bested suited for whatever I need to do at the time.

Not trying to be nasty or anything, just curious about what it is that made you reverse your opinion so completely on the issue in the space of two days' time?
And don't worry, I'm not going to be hounding after you or anything, it's just that I had posted in both the threads, so the post notification ebot brought me to the threads.

Quote - @luvver_3d:
I'm sure I just read your post in the Poser Forum where you quoted my opinion on 3ds Max 9's MR renderer vs. C5's renderer, and then replied that there aren't any advantages between one raytracer and the next.
Since "a raytrace is a raytracer."; how could anything assosciated with MR, then, have any qualities or advantages that are any different than 'any other raytracer'?
Every tool has it's advantages and disadvatages, is my opinion. I don't view it as somehow sacreligious to discuss them; and I use whatever tool I have that is bested suited for whatever I need to do at the time.

Not trying to be nasty or anything, just curious about what it is that made you reverse your opinion so completely on the issue in the space of two days' time?
And don't worry, I'm not going to be hounding after you or anything, it's just that I had posted in both the threads, so the post notification ebot brought me to the threads.

You obviously didn't read all my posts in the other thread, or you would have the answer to this already.  In the other thread, I said "raytracing is raytracing", and that's absolutely true.  For what operaguy wanted to do, any raytrace engine would work well enough.  You explain to me how reflections or refractions or raytraced shadows in Mental Ray are any better than the same things in Carrara or Vue.  They're not.  Why?  Because raytracing does the same thing in all of these apps.  Pretty reflections can be had just as well in Carrara as in Max or Maya.  End of discussion on that.

Now on the matter of the sss skin shader, we're no longer talking about RAYTRACING in and of itself.  We're talking about application-specific shaders that were designed specifically for working with a particular render engine.  Of course it's not the same.  In that case, one can be better than the other.

Anything else?

Would it be possible to fix Carrara's rendering engine, so it could do these layers, or do you think I'd be better off making several passes/renders of the model (using different materials an light settings), and compositing them? It's more work, but I don't mind.

Quote - You obviously didn't read all my posts in the other thread, or you would have the answer to this already.

Yes, I did, including the later post where you were arguing with person that posted his opinions about the MR in Maya.

Quote -   In the other thread, I said "raytracing is raytracing", and that's absolutely true.  For what operaguy wanted to do, any raytrace engine would work well enough.  You explain to me how reflections or refractions or raytraced shadows in Mental Ray are any better than the same things in Carrara or Vue.  They're not.  Why?  Because raytracing does the same thing in all of these apps.  Pretty reflections can be had just as well in Carrara as in Max or Maya.  End of discussion on that.

That paragraph implies to me a profound misconception of the entire raytracing process on your part, as you are oversimpling an vastly complex operation to the point of a check box for on/off.

Quote - Anything else?

Yeah, A few things:
-Monte Carlo Method.
-Metropolis Light Transport (w/ multiple intensity variant algorithms). <- kind of the same as the MC, but with some differences.
-Contrast controls (temporal and spatial).
-Multi-Pass Rendering.
-CAT Image Compositing.
-Selective Material Overrides.
-Mental Ray Connection Shaders on all material. <- you can omit that one, if you insist the renderer specific shaders are irrelevant.
-Material and Object based Photon Emission.
-Global Displacements.
-Volumetric Refractions.
-Final Gathering.
-Scripted Pre and Post Rendering operations.
There's more too, I'll see what you have to say about why none those have any direct impact on the rendering process compared to a raytracer that doesn't have them first.

Quote -
-Monte Carlo Method.
-Metropolis Light Transport (w/ multiple intensity variant algorithms). <- kind of the same as the MC, but with some differences.
-Contrast controls (temporal and spatial).
-Multi-Pass Rendering.
-CAT Image Compositing.
-Selective Material Overrides.
-Mental Ray Connection Shaders on all material. <- you can omit that one, if you insist the renderer specific shaders are irrelevant.
-Material and Object based Photon Emission.
-Global Displacements.
-Volumetric Refractions.
-Final Gathering.
-Scripted Pre and Post Rendering operations.
There's more too, I'll see what you have to say about why none those have any direct impact on the rendering process compared to a raytracer that doesn't have them first.

What do any of those features have to do with raytracing in general, which is the only thing I was referring to in the other thread?  Multi-pass rendering?  Global displacements?  None of these things have anything to do with either thread in question.  I never said Mental Ray couldn't do all these things, or argued that it wasn't a great renderer for those kinds of advanced features.

All I'm saying is that the process of raytracing IS general for the most part, and the same basic principals make up the process for every raytrace engine out there.  That is to say, raytracing is a process of following rays from a virtual eye or camera point OUTWARD, rather than originating at the light source.  It works by tracing a path from the imaginary eye through each pixel in a virtual screen, attributing the contribution of each light in the scene to that pixel.  As each ray is cast from the eye, it is tested for intersection versus objects within the scene. In the event of a collision, the pixel's values are updated, and the ray is either recast or terminated based on material properties and maximum recursion allowed.

So what are you in disagreement of again?

ccotwist3d
A multi pass composite might work, I've never tried it. That's interesting idea.
If you do try it, post about it here, or start another thread for it.

luvver_3d
I have a Master's degree in optics, you don't need to explain to me how raytracing works. There are several main types of raytracing and many variations of each of those. All of them have certain pros and cons, but some are better (i.e. more accurate, more efficient, etc.).
The best raytracers use several different types of raytracing algorithms in conjuction and have the ability to activate or deactivate different 'features' depending on whether you require extreme speed, extreme accuracy, or anything in between. The features (variations) are not always labelled as 'raytracing' but they require that raytracing is used to implement them.
Google "Monte Carlo Method" or "Metropolis Light Transport" if you don't know how those pertain to raytracing. I'd think you can find some information about them that way. You could also probably check out "Bidirectional Refractance Formula" too.

You are of the opinion that a non-distributed raytracing is equivalent to a raytracing done using sophisticated randomizing , distribution, and sampling algorithms. As long as it raytracing, it's the same result.
I disagree completely. I think that not all raytracers are created equal.
Just leave it that.
If anyone happens to stumble into this discussion, they can make up their own minds about which one of those ideas is the correct one.

No hard feelings, I hope. I get deeply involved in the technical discussions, because it is something I have been very interested in for a long time.

Thanks. I'll give it a try. I looked up some of the things you mentioned. It's interesting that an equation can be made to predict the path of photons the eye would encounter in an area, to create realistic light and shadows. Would you recommend some books, or websites I could learn more about raytracing, ambient occlusion, and sub-surface scattering from? I only have a rudimentary idea of how they work, but would like to know enough to be able to work with them without guess work.

Try the Wikipedia.
http://en.wikipedia.org/wiki/Category:3D_computer_graphics

It's got good general information and there's a lot of links to more detailed information to be found throughout the articles.

Thanks.