Shaders (sampler)
 

I am trying to creat a fake SSS effect and have been told that if I use the sampler node combinde with a ramp I can get the effect I am looking for. My problem is I do not know how to use the sampler node. I am actually pretty new to shaders all together and been having some problems finding anything to explain the basic consepts. So if you know how to use the sampler or just know of some where that I can learn more about shader let me know. thanks!

Sounds like there talking about a velvet shader there. Get on and disect it to find out how to use the sampler info node. is the best way.

how you put it togather might also depend on what you plan on useing when rendering. Do you know if you plan on useing the mayasoftware render on it ? or MentalRay with like FG on it ?

Let me know and we'll see what we can cook up.

Do you know where I can find a velvet shader to disect?
I am going to use mayasoftware to render.
Another thing that I am trying is to use a Anisotropic node instead of a phong or a blin for my base shaders in my shader, I am not sure how it will work but I will let you know.

You can find one on Highend3d.com in maya shaders section.

in the morning I'll see what I can cook up also as I'll probably need some velvet afeect before the challange is over anyway.

Ok, I found a simple velvet shader and am trying to recreate it. I tried to make everything the same but my ramp shader does not look right and it is not giving me the same efect. I have posted a pict of my hypershade and atribute editor. As far as I can tell everything looks and reads the same ecsept for what I have circled in red. Do you know what I am doing wrong.

Pony: I just wanted to say that I have been following your posts here ever since I started in 3d last year and have learned allot from your comments. So keap up the good work and thanks for the help!

Well I wouldn't know for sure unless I looked at the shader more. You can select the shader in the hypershade and export it. Up load it here. But from what I seen on the velvet on my computer, it looks like you might have the ramp pluged in to something other than the Incandescence of the Lamber or Anistrophic.. what ever your useing there.. Like the color channel maybe ?

There is some nice SSS efect that can be gotten from linking the sampler to the lights and this. Ever read Stahlbergs little tutorial on the fake SSS shader ? More just wandering, as there is one little thing he leaves out, LOL.

ah yeah. A reson why more I was just asking was becouse He did that tutorial befor the "Ramp shader" was put in to maya 5. The ramp shader can do what he did just a bit eazyer if you ask me. But eather way works.

If your intrested in his paper though :
http://www.optidigit.com/stevens/shadetut.html
PS I mentioned he messed up on one thing. Not really but he did forget to give the corect values for the clamp in that network.

PSS. thanks for your kind words.. yeah drop buy the thread and leave a note, always intrested in your thoughts.

Ok- I have checked to make sure my ramp is pluged in to my incandessince, and it is. I am not at home right now but when I am, probably tommarow, I will uplload what I have been working on.
I have been looking at Stahlbergs stuff as well as alot of other forums on skin shading over the last few days, but I just seam to be missing something. I feel like I have missed some foundational things that I nead in order to understand how this all works. I have worked for hours and hours just messing around in the hypershade but dont feal like I am making any real progress. I am not sure what I should do. I think I may take a break from all of this for a while and start working on another character. (Modeling is where my heart is)

It can be frustrating. Well send that fill I'll have a look. You know you can get on the IRC channel if you want. Things happen much faster on there. I'm there most of the day.. fakeing or even useing SSS isn't eazy yet. Some one corect me if I"m wrong but it wasn't even untill like last year there were any real and reliable SSS shaders for mental ray out there.

PS and you got some color in the color channel ?

Don't know if you've seen this or not, but it's a pretty good explanation of using SSS in Maya....
http://www.highend3d.com/maya/tutorials/misss/

[Edit] also found this for simulating SSS...
http://www.motiondesign.biz/sss_start.html

thanks mhcannon, I haven't used the misss yet.. just the pSSSt one..
Have you used both ways mhcannon ? I wandered how they stacked up.. the fake SSS mentioned there I don't think will work well for human skin but for thinks like wax it could be great . maybe faster..

Haven't tried the MISSS yet. This (and other threads) have sparked my interest in wanting to see what all the fuss is about regarding SSS. I have downloaded the shaders, and time permitting, I'll try it this weekend.

I have played the simulated and does a fair job of simulate nonorganic translucent material such as wax (ok that's kind or organic but I trust you understand what I mean), plexiglass, cast resin, polymeres and acrylics. But I agree I don't think it would be a good skin effect.

I'm still just a modeler, so I'm still feeling my way around lighting, shaders, rigging, etc. But I'm not in a huge rush to learn everything at once.

oh yeah guy's forgot. If you want to see what the pSSSt shader looks like look in my female WIP thread in my sig. pritty much used it out of the box like that.. besides changing the deapth a bit. Theres no textures eather so its not like a great example of what is posible with it.. but it does show what it might be like.

I did get the fake SSS of stahlbers to work and also my own verstion. But right about then they come out with the pSSSt so I figured why play around with the fake when you can have the real.. but I'm getting intrest in the fake again. I'd like to get a good fake sss working for the bones and stuff on my robot. It being a wight plastic thats not shiney all over.

Actully the first thing I started messing around with was misss,(the link that you provided) It was working ok, I had not quite figured out how to get it to work right, then I was told that I should try and figure out how to do fake sss because of render time. I want to use it for a project that I am working on that will eventually have a LOT going on. Now I am woundering if it really worth it. How much diferance do you think it really makes?

more of a guess but it can make a big, big difrance. the longest a shader that was fake SSS toke on the femail buy its self was about 34 sec, while the pSSSt shader ran it up to 5:00minutes.
If you do anything with finalGather FG or anything like that with occlution in MR you might want to as well stick with the SSS it will not take much longer than like FG will anyway. and the SSS has oclution bilt in to it.

Wandering, tell me aobut the scene and what you want to acomplish visualy with it ?


if you plan on doing a animation I do agree ya have to find good resonable time salutions . the animation on the robotic' horse neck was like 2:10 a fram something like 445 frames. with only FG at 600, where as I latter loaded up a dirtmap shader and it chucked out the frames at 42sec each. and looked better. Had I not finished most of it with FG already I would have switched for sure.

Pony:
I will try and describe the project I am working on. First of all there are 3 characters. The first one is the one that I am working on, (first realistic human, Post in WIP).
The animation will start of with the first character walking down a dark ally. He will get hit buy something but we will not see it. As he continues he will keep getting hit and pushed around by something we do not see. At the end he drops to his knees and then the whole thing rewinds. The whole thing starts again. This time the 2nd character is introduced. (The 2nd one is a Seraphim (Angel). I have attached an image. I want to use a lot of particle effects to give him a similar look to the picture from Nintendo’s “Geist”). You will see that he is the one that was pushing the first character around. It gets to the end and rewinds. In the third and final pass the 3rd character is introduced. (The 3rd is a fallen angel similar to the 2nd but decrepit. I want to make him very dark and he will leave trails of fire.) This time you will realize that the 2nd character was not beating him up but protecting him from the 3rd. At the end the first character prays (body language, there will be no talking), and than there will be a shot of the Fallen angel confronting the Angel. The Angel will open up his wing and brighten up. When this happens the fallen angel will go away. The Angel will then help the 1st character up and they will continue walking down the ally together.
I plan on showing allot of emotion in the 1st character as he is very proud and gets very upset at first. As the story progresses he will be humbled and realize that he is not able to do this on his own.

With all that said I have a question. I realize that this is going to take me an extremely long time. But is it worth it? In the end I just want to get a job. Would it be more valuable for me to just spend time modeling stuff? (I want to be a modeler). I have been struggling with this for a while. My school really stresses getting a finished product. But I am staring to wonder if that is really the best way to get a job. If I want to be a modeler wouldn’t it be better if I just had a bunch of stuff that I modeled?

here is the pict.

WOW, ok first, I'm way inpressed buy the story idea and way its reviled visualy. This is a kind of short peace that really trips my triger. I'll help in what ever way I have time for.

Do you have a larger image of that one that your trying to match the look of ? if so send it to pony2012@cox.net

At least the 1st character will need more of a normal SSS afect. And the little thing with the ramp and sampler will start you in a direction to fake a level of SSS that you will want but it will not be the only thing. I'll see if I can't find the siggraph white papers on the fake SSS they used in finding nemo. A good deal of that was in post if I remember right. It might be just the ticket for all the characters.

About your last coments.. Your going after a modeling spot, nothing wrong with that, and your right its a lot of work for a modeling demo real. If you want to put in the extra work though, and you can aford to, ei your modeling is top notch and your time would be better spent promoting your self and not learning some new modeling tricks. Thin I would say one way to set your self apart is to show that your models will work right under animation. Plus the shaps are more exciting when they move. You could have some one help you with the animation. Shows your familer with working with others. Also they get countless demo's of models on terntables I'm sure.. this will be a good way to set your self apart.. and not have them fall asleep on you.

Thanks Pony! That is very encouraging, just what I needed to hear right now. Any way I almost forgot about the velvet shader. For now I have found a go around. But eventually would like to get this to work better. I have used a ramp to make the edges translucent, not allot, but just enough for the light to shine threw giving the appearance of some sss. I put a blue back light just to give the idea. The nice thing about this is I wouldn’t have to animate the ramp for the color of light but the drawback is it only gives a small rim. For some of it that should be fine because my character will be in a dark ally but I will probably need more when I introduce the angel.

Edit:
after a few more test I dont think this is working like I thought it was. Back to the drawing board.

the velvet shader. This what I dowloaded to try and figure out how the sampler works, but I couldnt figure it out.

ok looks like a good velvet to me. Don't see the prob.

ok well Let me work up a shader. I'll do it in a bit as I got some work I need to do right now. What it will do is use the info node for light data to put the fake SSS afect in there. Along with a little bit of a velvet that is driven buy the amount of light so you get the soft velvet afect from miro hairs on this skin.

oh yeah. and it will be for MR also. MR is just as fast, if not faster than maya soft as long as you don't tern on like GI or FG. It also has more options for kool nodes to use.

Ok let me try and explain exactly what the problem is. When I apply the shader it give me the effect I want but in to many places. For example the stuff I circled. I could paint where I want more of the efect like the ear but I do not know how to get it not to happen in the unwanted areas and still keap the effect only on the places where I do want it to happen. Circled in green.

the miss will give you great results for your needs. and its fast. im doing some work with it now too.

Luke, sorry, had a bunch of stuff to get done. Long delay. Well far as I can tell your not against using a mix8layer node in mentalRay. You can get some nice stuff with that also, as far as fakeing or doing much more complex shadeing.

Anyway for a fake SSS and falowing what stahlberg did. I don't have it tweeked out but this little scene has his shader in it. Just hit render.

Pony: no worrys I have been busy myself. I will take a look at the shader. Thanks!
I started working on my angel. If you want, check it out in the WIP forum titled "Angel"