i never used the phong node. i thougt that the specular is the better specular node.

but from the beginning i noticed that the specular doesnt look realistic . it was not where it was supposed to be. in the manual there is of course no explanation. thanks again. it says that they are both the same.
i found today this
http://www.renderosity.com/mod/forumpro/showthread.php?message_id=3076494&ebot_calc_page#message_3076494
*''You can also use a Phong node instead of a Specular node to drive the gradient. The difference is that Phong calculation is strongest when the surface points at the light, whereas the Specular calculation is strongest when the surface, if it would be a mirror, would mirror-reflect the light into the camera.''

Phong is on the left, Specular is on the right.

Probably the Phong type is more correct, but either works in general. Whatever you have in C4D - if you can use it to drive the diffuse color gradient, do it.

and now it makes sense. the specular node is always a little pointed in the camera. the phong node is strongest when the surface points at the light.

so i rendered two images. the light is above the ball. dont you think the phong node is more realistic? 

first image above is more unrealistic IMVHO.
it would be better to test this on human skin/hair models, as that's what they want to look good in poser.

Phong shading is a superset of the Gouraud shading system, where specularity is calculated using a normal and the reciprocal of  "roughness" parameter. It's a lot like Blinn shading but computationally less expensive. It's great for plastic and with the roughness spread far enough and intensity dialed down - makes great skin.

The first image (phong) looks unrealistic to me.

The reason I think it looks unrealistic is that the shadow indicates that the light is directly above the sphere, but the highlight indicates that it is beyond the sphere (since it is reflecting off the top at a very low angle of incidence).

In the second image, both the shadow and the highlight indicate that the light is directly above the sphere.

Phong is wrong - don't use it. It was invented in the 70's because it was cheap to calculate. It did not bother calculating the angle of reflection. It simply puts the highlight pointing straight at the light. You cannot get ANY rim lighting effect from a Phong, because if the light is behind the figure, then the hotspot is behind the figure, too, not the edge. It only uses light vector and surface normal. It doesn't respect the location of the camera.

The Specular node is better, but does not accurately portray surfaces with microscopic bump like skin. But at least it gets the position of the hot spot closer to the right place. It does not produce a proper rim-light effect, because it has no concept of the Fresnel effect.

The Blinn node is the best, as it does a good job approximating the position of the hot spot and the full relationship between surface normal, light vector, and camera vector that leads to variation in hotspot shape and luminance.

Remember, specular type nodes are a cheat altogether. Blinn is the least cheat.

Note: I sometimes use the Phong node, but not to render it. I use it to find out if the surface is pointing straight at a bright light.

thanks BB for the explanation.

what do you mean you use it to find if the surface is pointing to a bright light? 

The Phong node generates its strongest output when you're on a point of the surface that is pointing to a light. So one of the ways to fake SSS is to use a Phong node to control it. Front-side SSS is strongest when the surface is NOT pointing at a light. So I can get this behavior if I make the amount of SSS (redness) inversely proportional to how much output I'm getting from a Phong node.

Phong is wrong - don't use it.

Even if your model is , in  fact, wearing a very skimpy tight phong?
You still should not use it?

Quote - The Phong node generates its strongest output when you're on a point of the surface that is pointing to a light. So one of the ways to fake SSS is to use a Phong node to control it. Front-side SSS is strongest when the surface is NOT pointing at a light. So I can get this behavior if I make the amount of SSS (redness) inversely proportional to how much output I'm getting from a Phong node.

this is different then VSS skin shader right?

the old cheat witt specular connected to a blender node?

Actually if you follow all the math in the VSS shader, this is how it works. It's just not so explicit.

In VSS PR3, the specular layer steals some light. Only what is left gets to the diffuse calculation. The diffuse layer steals some more light. Only what is left gets to the SSS calculation. So in effect, the SSS is weak when the specular is strong.

what happens if we use only diffuse? only SSS?

In the PR3 shader if you set the PM:Diffuse Reflectivity to 1, you get no SSS, because then the diffuse layer uses all the light. If you set it to 0, then you get only SSS, because then the diffuse layer uses none of the light.

I demonstrated this in the VSS thread. This render has the diffuse layer turned off.

i noticed i didnt ask right. what if we use only diffuse in the light. does this mean that it will use everywhere SSS?

Yes but the amount will vary.

aha thanks.

something else.
this is from the SSS paper.
notice how the bump with SSS looks more soft? less bump? 

i think we could use something like this in the skin shader. i am now playing with nodes.

VSS does that already. The more SSS you use, the less bump there is. The reason is because the SSS is less dependent on viewing angle.

@ bagginsbill: You really ought to put your VSS shaders and such in your signature as a download, so they can be found more easily. I find these discussions educational, but always forget to find the latest shaders you're working on.:laugh:  Damn my lousy short-term memory!

Done.

Yes, I second that idea of putting those links in your sig. I've searched more than once for a link to your site.

Quote - Done.

Thank you!  You are a HUGE help around here, and your work on Poser is appreciated by me. I'm sure I'm not alone in that, but can only speak for myself.

Quote - VSS does that already. The more SSS you use, the less bump there is. The reason is because the SSS is less dependent on viewing angle.

i think it does not. i tryed now some renders and the bump is the same. 

Quote - I think it does not. i tryed now some renders and the bump is the same. 

Aaahh. Just tested with PR3 and you're right, it doesn't smooth it. Months ago I had a shader that did, but I changed how I fake the SSS and now it doesn't. Sigh.

It's very difficult to exactly fake the SSS. My shader cannot produce that look of translucence on a small scale. All it does is get the general large-scale color closer to that which would be produced by SSS. But to get the real effect, we need the real physics to be modeled.

It's like I'm trying to simulate the physics of a bouncing rubber ball, only my ball model doesn't flex and compress. So such a simulation would behave directionally correct in that the final trajectory of the ball would be about the same, but during the actual bounce event it behaves like a billiard ball instead of a basketball.

Similarly, the overall color of my shader is directionally correct in that the large-scale illumination looks similar to SSS, but the details are different.

yeah i understand that we are only faking the color. but with this bump effect i think we could make it look better in close ups.

this is what i was trying. with specular or with the toon shader. the specular is better but if you  use a lower specular on the light it changes .

if  we could make this work then it would look more ''softer''.

Iin that setup, the bump is strongest where the specular is strong, which will maximize the bump appearance, because bump is revealed by specular more than diffuse. Don't you want to minimize it there?

Also, this situation and similar ones have always mystified me. Why is Poser not in an infinite loop?

As you've set it up, consider this:

The specular consults the normals and the camera position and the light position.
The normals consult the geometry and the bump.
The bump consults the specular and the Spots.
The specular consults the normals and the camera position and the light position.
The normals consult the geometry and the bump.
...

Why does it work, or does it?

There are cases where THAT might be useful.  Not for most skins, but for reptile scales and such it would kick butt.

i actually dont know exactl what i  have. i wanted to do something similar like in two pics that i posted.
in theory where the SSS is strong there should be less bump. right? 

bagginsbill how would you do it or how did you do the trick with the bump? 

I have no idea what Poser really use, but the Phong and Blinn model are very similar, both use the incident light angle, camera direction and the normal of the point where's the illumination is calculated. The only difference is the mathematics on how these angles are used and in both cases the mathematics are very simple and give in most of the cases the same result. In many cases in 3d engines what is called Phong is really Blinn and what is Blinn is really Phong and beside academical purism it makes no difference the confussion.
The Blinn or Phong models are very simple, give acceptable result, but are NOT physically correct.
There are many models that are physically correct and are mathematically complicated with the consequent big computation time.
The model to be used depend on the object, there do not exist an unvirsall model, the model tio be used depend on the BRDF of the object, research this term (BRDF) for more information.
For example, for metallic surface there is the Torrance model that is physically correct and produce reallistic rendwerings, but the Torrance model only worls for metallic objects. For rough surfaces you have to use other model, for dusty surfaces such as the Moon you need another model and so on.
Human skin requires another different model and is difficult and complicated for producing reallistic results (dielectric, sub surface scattering) and what is worst, human skin has hair!!! and this nobody takes into account....

Kawecki,

We're not talking about the Blinn or Phong models. We're talking about the Poser Phong node, Specular node, and Blinn node.

This thread started asking about the Phong node.

As I already said (perhaps you did not read my post) the Poser Phong node does not use camera direction, only incident light angle and normal. So I said don't use it at all.

For human skin, the Poser Blinn node is closest. And I do take into account hair in my skin shaders, which generally run between 40 and 120 nodes. Or when you said "nobody" did you mean me?

That seems to be a pattern lately. Someone says "that's impossible in Poser" and it actually means "only Bagginsbill knows how to do it in Poser".

"Nobody can do it" means "Bagginsbill can do it"

"Nobody pays attention to body hair" means "Bagginsbill pays attention to body hair"

Yeppers, BB!  Your the most famous nobody around here, when it comes to node-mastery!:laugh:

Nobody is as respected as you!:lol:  Sometimes, you just have to laugh at it all.  You're ALWAYS educational, IMO.  I like learning new things.

i think using hair on the skin should be the last stepp. those are extreeeeeeeeeeeme mega big details for skin.
yes i know that they are there. but the basics should first be used. lighting,SSS,shadows and a good texture image.

i saw 100 renders on the internet with good skin. and they didnt use those small details like hair.

Quote - As I already said (perhaps you did not read my post) the Poser Phong node does not use camera direction, only incident light angle and normal.

As I said before, I have no idea what the Hell Poser does inside.

Phong model
Takes the incident light ray and creates a reflected ray using the normal at the point (incidence angle = relexion angle), next is calculated the angle between the reflected ray and the camera direction.
The illumination is the cosinus of this angles raised to an exponent ( the Se value in the mtl file of the obj file, or 100 - Poser's 4 dial).

Blinn model
Is calculated a ray that is half-way between the incident angle light and the camera direction, the is calculated the angle between that direction and the normal at the point.
These angle is used in the exact same way as the Phong model does.

If Pose does not use the camera direction in its "Phong" node what Poser has subverted the name Phong and have not used instead, for example, the "E-frontier" node???

Quote - think using hair on the skin should be the last stepp. those are extreeeeeeeeeeeme mega big details for skin.
yes i know that they are there. but the basics should first be used. lighting,SSS,shadows and a good texture image.

i saw 100 renders on the internet with good skin. and they didnt use those small details like hair.

As I said before. people forget and ignore that skin has hair and is not difficult to include the "hair effect".
You need not to create millions polygons of millions hair filaments, it's a waste of resources and computer power that leaves nowhere in the result.
Skin hair is not visible in normal conditions and is the person is hairy is just enough to use a good hairy texture, and a rendering that shows the hair detail is useless, for what need you to render  an image that is nothing more that some few incjes of a skin?
Skin hair is only visible at the borders of the figure and only if is illuminated in certain way, so it will not be difficult for a rendering engine to create some blur outside the contour surface to simulate the effect of the difraction and scateering of the light due the hair filaments, and this effect is clearly visible in every day's life!
There's no way to create this effect using nodes, it must be done inside the rendering software.

The hair effect II
And is not only the hair, it applies to many other things too.
Create a scene with only one light, put the light behind some object and render the scene. You will have a black screen.
This doesn't happen in real life. In real life you see the contour of the object and the illumination extending to the front decaying quickly as you move to the front. At the border of the silhuette you can see, depending on the object, hair, air dust, vapours,k air turbulence, translucencies, etc.
For creating this effect you need:

1- The light illumination must go above the 90 degree angle with the normal, decaying quickly above 90, but at 90 degrees is not zero.

2- To exist a zone between the very well defined ploygon surface and some distance from the polygons, only is needed at the silhuette.
This zone cannot be well defined, so it cannot be made of polygons, unless you use a transparency plane, This zone can be made with prodedural nodes,
A transparency plane can work fine, but if you change the camera angle or the light direction, you need to create another contour plane and another transparency map.

3- The plygons at the silhuette cannot be well defined, it must be somehow blury. Even if you managed to create a good transparency plane the overall result will be unreal because you will see a very sharp transition between the transparency and the very well defined plygon surface.

Solving 1, 2 and 3 you can have skin hair, clouds, glows, smoke, ghosts, fxs and many other things.

yes i agree that if you have a light behind he object it should not be black.

Kawecki,

You do like to go on and on, eh?

It is not particularly helpful that you come into a thread about how to use the Poser specular nodes, shouting that you don't know anything about Poser specular implementation.

I wish you would stop. Since you said "I have no idea what the Hell Poser does inside", and since I'm trying to help people understand what the Hell Poser does inside, and since I know exactly what the Hell Poser does inside, and you seem in some cases to be "educating" or correcting me, all you're doing is confusing people and making my attempt to help people understand what to do with Poser more difficult.

Your explanation of the Blinn MODEL, for example is just not helpful. Your observation that the Poser nodes are misnamed is irrelevent.

It might have been interesting if you'd discussed the Torrance-Sparrow model, because it does attempt to do the silhouette effect, also known as rim lighting, and the Poser Blinn NODE implements the the Torrance-Sparrow model, not the Blinn model.

But throwing all these model and node names around doesn't help people - it confuses. I don't like it when I'm trying to help people and others come in to confuse them. I'm going to have to explain everything 3 times over now. The Poser Blinn node is not the Blinn model. Shut up about the Blinn model.

And next time you want to give a lecture that only 1/100th of the people reading this can derive any benefit from, perhaps it would be good to just show them a page where it is completely explained and let them read all about it somewhere else.

Like this page: http://www.siggraph.org/education/materials/HyperGraph/illumin/specular_highlights/blinn_model_for_specular_reflect_1.htm

Quote -
I wish you would stop. Since you said "I have no idea what the Hell Poser does inside", and since I'm trying to help people understand what the Hell Poser does inside, and since I know exactly what the Hell Poser does inside

No, you don't know. If so, tell me why what you see in preview mode is not the same of what you see in the rendering. It's obvious that the preview and render illumination models are different, why???, it's anoying!!

Quote - It might have been interesting if you'd discussed the Torrance-Sparrow model, because it does attempt to do the silhouette effect, also known as rim lighting, and the Poser Blinn NODE implements the the Torrance-Sparrow model, not the Blinn model.

For what, the Torrance model is too complicated and is only valid for metallic surfaces.
Maybe the Poser's Torrance node or Blinn as you call it has nothing to with the real Torrance BRDF model.
One more confussion and missuse of names???

Quote - And next time you want to give a lecture that only 1/100th of the people

Wel, for 1/100th of the people is useful, I never pretended to be populist, I let this task to the

I have an useful link too:

http://www.realtimerendering.com/

NOTE:
In the real Torrance model does not exist diffuse, ambient and specular components, it only exist the Totrrance BRDF and nothing more.

Quote - It's obvious that the preview and render illumination models are different, why???, it's anoying!!

Because the preview (whether it's being done by OpenGL or SreeD) can't be the same a raytraced render.
How close it can get depends on what effects can only be done at render time, e.g. displacement and full shader evaluation.

@ kawecki - bagginsbill has an abrasive way of making a point -- I hope he won't mind me saying so, knowing that I would not change him -- but I'm afraid he is right: this is not the place for in-depth explanations of lighting models that are not implemented correctly, or at all, within Poser. They are a very unwelcome distraction.

Those who are interested can read up about them elsewhere.

We know that Poser is an inexpensive and far from perfect 3D modelling tool, but in knowledgeable hands it can do a reasonable job, and that is what we are trying to learn here. BB's claim that he has an in-depth knowledge of the program is not exaggerated or boastful -- it's a simple fact.

So, with respect for your knowledge in other fields of expertise, please let's keep the discussion to what we can do with Poser, and how to do it.

Thank you
Izi

Quote - > Quote - It's obvious that the preview and render illumination models are different, why???, it's anoying!!

Because the preview (whether it's being done by OpenGL or SreeD) can't be the same a raytraced render.
How close it can get depends on what effects can only be done at render time, e.g. displacement and full shader evaluation.

Is not so simple, raytracing use an illumination model, OpenGL use an illumination model, any software renderer as Poser4 also does. If all use the same illumination model the scene will look the same, the only difference is the quality, detail and size of the rendering.
You needen't displacement, antiallialing, perfect shadows in preview mode, you only need the preview to look similar to the final hi-quality render, so you can place and pose the objects for making your scene and not to use trial and error method trying to guess how your image will look.
There are some things that only can be done with raytracing, but if you look in the gallery images is very rare to find miirors and refractions and so what can be only done with ray tracing is seldom used.
I am speaking of a simple figure with a floor and background illuminated by one directional and two spot lights, no displacement, no bumps, no mirrors, no refractions, no special fxs even no shadows, nothing that requires raytracing, all can be done in real time, the image should look the same in OpenGL, Poser4 preview, Poser4 render and firefly render, but it is not.
But the result using raytracing or the old Poser4 render is almost the same. The only conclussion that I can reach is that Poer's raytracing use the same illumination model of the not-raytracing Poser4 and inherited all the problems of Poser4.

Quote - So, with respect for your knowledge in other fields of expertise, please let's keep the discussion to what we can do with Poser, and how to do it.

Many things can be done with Poser. I almost do all my rendering in POser and still in Poser4!!! without any post-work, you have nearly 500 images in my gallery and all were done with Poser and many things were done, some are very good.
I love Poser, is a good software and easy to use, but for making something in Poser you must to know the limitations of Poser, what Poser does in the wrong way, how things work and find a way to cheat Poser for making it do what you wants.....