Thanks hborre,

I have no hesitation in purchasing the product. I meant his latest and greatest. I checked his store, which has some dreamland models (including one car), but I was unsure if that one car has it or just which products have the latest shaders.

It isn't really clear to me what I should purchase if I want particular shaders. Like which, if any, product has his leather shaders?

Do extra lights increase render times more so than objects? I am sort of assuming that they do, since Poser would need to make ray trace and IDL calculations for every light wouldn't it?

Quote - Do extra lights increase render times more so than objects? I am sort of assuming that they do, since Poser would need to make ray trace and IDL calculations for every light wouldn't it?

Lighting is a major contributor if the scene is saturated with them.  Other culprits are hires textures, high polycount models, displacement maps, transparency maps, extremely high render values, etc.

Quote - I have no hesitation in purchasing the product. I meant his latest and greatest. I checked his store, which has some dreamland models (including one car), but I was unsure if that one car has it or just which products have the latest shaders.

Any product with BB's name associated will contain his unique shader setups.  Purchasing them does not restrict you from using the shaders in other products.  Use them as you see fit and necessary.  But be warned, some of those shader arrangements will make your eyes cross.  They can be very...elaborate.

Quote - Any product with BB's name associated will contain his unique shader setups.  Purchasing them does not restrict you from using the shaders in other products.  Use them as you see fit and necessary.  But be warned, some of those shader arrangements will make your eyes cross.  They can be very...elaborate.

I already have an appointment to see if they can uncross my eyes...

Wow, that's an amazing render of the motorcycle, thank you for the info....agh! I've so much to learn!

<wearily pulls his head up out of the Poser Manual, blinks a few times, and then raises his hand>

So I have some questions already. I am reading about the root nodes at the moment, and more specifically the PoserSurface Root Node.

Diffuse Color states that it is the surface color multiplied through any light striking the object. I am not sure I fully understand that statement. My limited understanding of color and light is that it is always reflected light hitting our eye. So something appears Red because it bounces the red parts of the spectrum and absorbs the others.

So what exactly does it mean when it says, "surface color multiplied through any light"? Why multiplied and not added, or some other math function?

Fresnel Blend:

Outer Color is defined as the color of the surfaces facing away from the camera. When I think of outer color and inner color, I think of a sphere with the light (or color) outside of the sphere and the light (or color) that is inside the sphere. This seems to imply the opposite: that outer color is the color of the parts of the sphere that are on the inside or facing away from the camera.

Similarly for Inner Color, it is defined as the color of the surfaces facing towards the camera, which is what I would consider the outside of the sphere.

Can someone explain this a little better?

Quote - Fresnel Blend:

Outer Color is defined as the color of the surfaces facing away from the camera. When I think of outer color and inner color, I think of a sphere with the light (or color) outside of the sphere and the light (or color) that is inside the sphere. This seems to imply the opposite: that outer color is the color of the parts of the sphere that are on the inside or facing away from the camera.

Similarly for Inner Color, it is defined as the color of the surfaces facing towards the camera, which is what I would consider the outside of the sphere.

Can someone explain this a little better?

I believe you are confusing outer and inner with exterior and interior.  Outer refers to the edges of a sphere, for example, which are moving away from the camera. Or facing away from the camera.  Inner is the surface closest to the camera, or facing the camera.  

I'll be back to help soon, but I'm super busy with work at the moment.

Our renderer models light as having only three spectral elements - red, green, and blue.

The multiply is correct for diffuse reflection because the incoming light has some percentage absorbed, and the rest reflected. The diffuse color is 1 - absorption values.

Suppose half red is absorbed.

Incoming light is, say [.8, .8, .8]. The diffuse color (absorbing half red) is [.5, 1, 1].

Multiply them together and you get [.4, .8, .8]. See ? Half the red got absorbed.

Try it with other values. It always works.

Another way to look at diffuse color is this: it specifies what is reflected, given a reference light source [1, 1, 1]. Therefore, if the light is half that bright, [.5, .5, .5] then the diffuse reflection would be half the original diffuse color, or color * [.5, .5, .5].

If the light is pure blue [0, 0, 1] and the surface is pure red reflector [1, 0, 0], the resulting reflection is black i.e. nothing [0, 0, 0].

Quote - I believe you are confusing outer and inner with exterior and interior.  Outer refers to the edges of a sphere, for example, which are moving away from the camera. Or facing away from the camera.  Inner is the surface closest to the camera, or facing the camera.

Yes, I think so too. So let's take a balloon as an example. The outer color would be the inside surface of the balloon that faces away from the light, and the inner color would be the outer surface facing the light?

Or the outer color would be the back face of the ballon that's on the far side away from the light source, and the inner color would be the forward face of the balloon that is facing the light source?

Or both? :)

I did send you the stuff to understand it better, it's all in there (at least, I tried). Comments welcome.

Anyway. If the light has color RGB = (80%, 60%, 40%) and the surface has color RGB = ( 70%, 50%, 30%) then the result is RGB = ( 80%x70%, 60%x50%, 40%x30% ) = (56%, 30%, 12% ). It's actually called filtering, like you're looking through a colored semi transparent piece of plastic.

In real life, metals do look red (eg copper) because there is more red light reflected than green and blue light. Flowers do look red because all light is absorbed and then rediffused, and in that process the red light is absorbed least. Objects do "emit" from diffusion, reflection, translution, fluorescense and phosphorescense behaviour (and because or transparancy which lets light shine through from the backside). 

Poser only handles surfaces, it hardly deals with volumes. So there is no such thing as an "inside color". But when the camera looks at an object, the edges it sees are outside, and everything between the edges is inside.

have fun.

That all makes sense to me Bagginsbill. One clarification though: you are talking about what I said with the color of an object being what light we see bounced off of that object when you say, "diffuse reflection" correct? 

Or are you more specifically discussing what is referred to as Diffuse Reflection in the article that you posted in this thread?

http://forum.runtimedna.com/showthread.php?44077-What-exactly-do-Diffuse-Specular-nodes-do&p=500402

I haven't delved into the stuff you sent me yet aRtBee, but I will! Oh I will! :D

Quote -  Poser only handles surfaces, it hardly deals with volumes. So there is no such thing as an "inside color". But when the camera looks at an object, the edges it sees are outside, and everything between the edges is inside.

Oh! Is that what it means?

Lighting nodes: Anisotropic, Phong, Glossy, Blinn, and Specular.

These all appear to do the same thing. So why would you use one over the other?

I unsubscribe. It's in the text I send you. This is very disappointing.

As I said yesterday aRtBee, I will not have a chance to read those until this weekend.

The terms refer to surfaces facing the camera (inner from camera's point of view) versus facing away from the camera (outer edge of object from camera's point of view).

The Fresnel effect is a function of the angle of incidence between the surface normal and the observer (or camera).

When you look at a surface from a shallow angle (when it's not pointing at you) then it reflects more. Way more.

Typical smooth glass, with IOR = 1.5, has an inner (facing you) reflection coefficient of just 4% whereas for surfaces near 90 degrees to the side it is 100% reflection - a perfect mirror. Exactly how the transition goes from inner to outer is a complicated equation called the Fresnel equation. I have been using this equation in my shaders for years, built from 21 math nodes. Now Poser has it in one node - Fresnel_Blend.

Study the annotated render attached.

Quote - That all makes sense to me Bagginsbill. One clarification though: you are talking about what I said with the color of an object being what light we see bounced off of that object when you say, "diffuse reflection" correct? 

Or are you more specifically discussing what is referred to as Diffuse Reflection in the article that you posted in this thread?

Hmm. Diffuse reflection is an effect. I use the word reflection or reflect in regard to the phenomenon of bounced light. Diffuse reflection is a particular and specific bouncing behavior that differs from specular reflection and also differs from subsurface scattering.

Diffuse color is a parameter used in the simulation of that affect in just about every renderer ever written. Color (the word unadorned, no adjective) is a subjective experience and may not match the diffuse color, as it combines ambient light, direct light, viewing angle, specular reflection, contrast with surroundings, diffuse value, and so on. This is not a good definition for color so we'll dismiss it.

Many parts to the rendering equation, of which diffuse color is only one, lead to specific and unambiguous color - a pixel with a specific RGB value in your render, which came out of the shader that decided it. So let's go with that one.

If you're going to want the exact definition of terms, we have to be much more careful than we've been, as we in the community tend to get pretty loose with words.

When I am doing shader-talk, diffuse color in a shader is something very specific:

It is the ratio of reflected light color versus incoming light color, assuming the incoming light angle is uniformly 90 degrees. In a Poser shader root node, the diffuse color (ratio of bounced light color versus incoming light color) is actually the product of two values:

Diffuse_Color * Diffuse_Value

You can say that for light arriving at 90 degree angle of incidence, in a shader that is only doing pure diffuse reflection calculations, and has no specular effect in it, and has no transparency or refraction either, and given incoming light color L, the output color (C) is given by

C = L * Diffuse_Color * Diffuse_Value

Rearrange that to make the ratio C/L and

C/L = Diffuse_Color * Diffuse_Value

C/L is what I call the diffuse color (plain English). When I write, instead, Diffuse_Color, I'm referring to the Poser node parameter of that name, which is NOT in fact the diffuse color, although it affects it.

However, if you agree to force Diffuse_Value = 1, then it drops out of the equation and then, indeed, diffuse color is exactly the same as Diffuse_Color.

C/L = Diffuse_Color * 1 = Diffuse_Color

Many other shader systems (particularly Renderman) often refer to diffuse color as Kd.

Excellent! Thank you.

Mostly I did not want to make the mistake of assuming you meant something else that made more sense to my currently simplistic understanding. I really appreciate you taking the time to clarify that. :)

Quote - Lighting nodes: Anisotropic, Phong, Glossy, Blinn, and Specular.

These all appear to do the same thing. So why would you use one over the other?

All appear to do the same thing? Literally they appear the same to you? If so, you're observation skills need sharpening. Let's get on that, right now.

I'm going to set up some pawns with each of these effects and we'll see if they appear to do the same thing.

However the differences in performance have long ago dropped out of the matter. Modern computers implement sines and cosines just about as fast as add and subtract.

Left to right, anisotropic, phong, glossy, blinn, specular.

Of the five, only blinn is moderately accurate in the backlit case.

Again, the blinn is most accurate. However, the anisotropic is more correct in a certain special case - a surface with repeating or semi-regular parallel groves. Anisotropic is better for nylon, brushed metal, and a few other special cases.

I wish SM would create an anisotropic blinn, and an anisotropic Reflect node. Then we'd have an easier time with brushed metal.

Phong (#2) is mathematically the simplest and the most wrong. It's reason for existence is nothing more than to let you keep using 20 year old shaders that used to matter for performance on 386 and 486 CPUs. Professionals haven't used this model since the 80s. Just forget it.

Glossy (#3) is also a cheat for special cases from the 90s. When all your lights are point sources (having no width or height) then the speculars are never looking like you get from large, close light fixtures. The glossy node fakes it - it can pretend that your infinite or spot or point lights (all of which have no width or height) are actually circles. With the advent of area lights in the 90s, this model became pointless. With the advent of real ray tracing and real-dimensioned lit objects or environment sphere (i.e. now), it is even more pointless.

Specular (#5) is OK, but really why bother. Blinn is the right one.

The outer ring of the BBLightMeter is black. That's your clue that the specular nodes don't see anything in this scene.

I always use reflect and fresnel blend for realistic specular reflections of the actual scene.

In this case, my shader is doing both reflect and blinn. Getting the two effects to be consistent and harmonious is not obvious, and I believe that in the Poser world, I'm the only one that has worked out the math so that it comes out right in every possible amount of blur.

This is something I'm now building into a whole bunch of new shaders - BBGlossy2, BBMetal, BBCandyPaint, etc. None of these are released yet - I'm still not satisfied with them until they're absolutely perfect and absolutely easy to use. Hopefully soon, though, they'll be available, because EZMat is giving me a whole new way to distribute, configure, and apply these shaders that is much more satisfactory than me giving you a runtime with 3000 materials in it.

It looks like rubber because it is doing a soft (blurred) specular reflection of the white sky and the white floor. Without that reflection, it would just be mostly black and would not look real. None of the specular nodes do that - they don't look at props, only lights.

Quote - All appear to do the same thing? Literally they appear the same to you? If so, you're observation skills need sharpening. Let's get on that, right now. I'm going to set up some pawns with each of these effects and we'll see if they appear to do the same thing.

Ooops! Really poor choice of words there on my part. I was reading about the Material Room in the Poser Manual at work yesterday on my breaks. The definitions for all of those nodes are almost identical, so they sound like they all do exactly the same thing.

My bad! :)

I think I got it now.