What's "PBR"?

WillowRaven

I'm doing my best to find cheap or free iray shaders so I can finish this cursed project since the armor I'm using screws with Daz unless rendered in iray, which I've never really done, and am fumbling my way through to re-dress everything else in my scene to accommodate one tiny element (Orlean's Armor). So, while sorting through the various set I either already had or just acquired, I'm labeling them in categories I can more easily find what I want for my scene and came across one folder simply named 'DAZ Uber' and within it one named ' Iray Uber Base' and one named "4-layer Uber PBR MDL' ... Can anyone explain these to me (someone who knows little about how iray shaders and shader presets work)?

Richard Haseltine

PBR = physically base rendering, essentially trying to mimic the way the physical world behaves. Iray Uber Base is the default Iray shader, used by most products (there is, with Genesis 8.1, a new PBR Skin shader specifically for skin); the 4-layer Uber shader is like the Uber base but set up to allow layering; it's an add-on and not used often, if at all, in pre-made materials from other sets. (MDL is the shader language used for Iray, as RSL was for 3Delight.)

Diomede

The Chicago World's Fair of 1893 (World Columbian Exposition) was a watershed event.  It was a coming out party for Chicago and the American midwest and its spirit of growth, progress, new technologies, etc, etc, etc.

Like most fairs, there were prizes for flowers, livestock, cooking, etc, etc, etc.

One of those prizes was for the world's BEST beer.  The very best.  No etc, etc, etc.

The winner of the best beer at the 1893 World's fair was Pabst beer, a Milwaukee beer credited back to 1844, which is old in American Midwest time.  The prize was a blue ribbon.

Pabst Blue Ribbon (PBR), the world's best beer since 1844, recognized as such since 1893.

More details are provided by the knowledgeable folks at The Smithsonian Institution.  See

https://www.smithsonianmag.com/arts-culture/where-did-pabst-win-that-blue-ribbon-138975181/

.

WillowRaven

Richard Haseltine said:

PBR = physically base rendering, essentially trying to mimic the way the physical world behaves. Iray Uber Base is the default Iray shader, used by most products (there is, with Genesis 8.1, a new PBR Skin shader specifically for skin); the 4-layer Uber shader is like the Uber base but set up to allow layering; it's an add-on and not used often, if at all, in pre-made materials from other sets. (MDL is the shader language used for Iray, as RSL was for 3Delight.)

Ummm ... Still Greek ... So what do they do ... will I ever use them or do they just sit in the background to make all my other shaders or shader presets work right? 

 

McGyver

Physically based rendering seeks to super accurately simulate the way photons (the bitty-bitty bits o' light particles) behave in the real (physical) world, within the virtual 3D world... the way they bounce and reflect, refract and complain about not being paid enough to do all that neat stuff... the algorithms that drive the technical interpretations of how that should all work out are based on aspects of all sorts of real world details that are mathematically simulated within the 3D environment.

"Physically Based" is sorta like "as close to simulating real life as currently possible in a virtual environment"...

PBR shaders generally have loads more channels, nodes, input boxes and other doohickeys for relevant data to be input so the material the shader is trying to simulate can be accurately rendered... like for example a good PBR shader can simulate an automotive paint by simulating the depth of the paint, the metallic flakes within the matrix of the paint and the gloss clear coat (as well as a buttload more data*)... whereas a non PBR shader is severely limited and has to fake the look.

Good PBR shaders rely more on scientific data... non PBR rely more on making it look as close as possible.

That's probably not at all helpful, but anything else would just be to point you to a link that's basically a scientific dissertation on light transmission with the 3D Blah, Blah, Blah, blah, blah... and next thing you know you are waking up on the floor three hours later with a severe cramp in you side because when you passed out from boredom, you dragged your keyboard down with you and now you have QWERTY dents in your ribs.

 

*Thats an actual scientific quantification.

margrave

WillowRaven said:

I'm doing my best to find cheap or free iray shaders so I can finish this cursed project since the armor I'm using screws with Daz unless rendered in iray, which I've never really done, and am fumbling my way through to re-dress everything else in my scene to accommodate one tiny element (Orlean's Armor). So, while sorting through the various set I either already had or just acquired, I'm labeling them in categories I can more easily find what I want for my scene and came across one folder simply named 'DAZ Uber' and within it one named ' Iray Uber Base' and one named "4-layer Uber PBR MDL' ... Can anyone explain these to me (someone who knows little about how iray shaders and shader presets work)?

In the real world, when light hits a surface, its rays bounce off and hit other surfaces. The type of material determines which wavelengths of light are absorbed and which are reflected. That is why color exists, including indirect illumination and reflections (the different between the two comes down to how smooth the surface is). All of them are due to light bouncing off surfaces.

Physically-Based Rendering emulates that by emitting light rays from lights/emissives and modelling how they bounce onto all the surfaces in your scene. The roughness, normal, and bump maps that come with Iray shaders determine how the rays will bounce off the simulated surface. That's the secret to getting photorealistic renders.

The Iray Uber shader is already a PBR shader, since it has a metallicity/roughness model. Based on this thread (https://www.daz3d.com/forums/discussion/381156/how-do-you-use-the-4-layer-uber-pbr-mdr-shader), it seems like that shader is specifically used for layers in environments.

Artini

More practical way:

- You install Unreal Engine 4

- You download for free Quixel Megascans PBR materials from Epic store - there are a lot of them (159 packages at the moment)

 https://www.unrealengine.com/marketplace/en-US/profile/Quixel+Megascans

- Using https://www.daz3d.com/daz-to-unreal-bridge you transfer any Genesis 3 or 8 based characters you like

 and play with them in UE4

Artini

If it is not enough, you download for free https://quixel.com/mixer using your login for Unreal Engine 4.

Then you can retexture any 3D asset with smart materials.

After that, you should have pretty good idea, what PBR is all about.

 

WillowRaven

Wow ... Thanks, everyone :)

TheMysteryIsThePoint

Even though it's for Blender, the Cycles Encyclopedia provides the best explanation of how ray tracing works in genreal that I've ever read.

WillowRaven

I'm used to ray-traced with 3DL shaders.

nemesis10

If you are used to ray-traced 3dl shaders, one thing you may have noticed is that they were strange in terms of reflections.  The early Poser and Daz figures had little textures that simulated reflections in eyes; in current PBR based Iray characters, corneas glint because they are wet and wet things reflect well.

fred9803

The first time I heard the term "PBR shader" used in Daz store was with The Velo bicycle. Applying the DS Iray Uber Base shader to a surface will convert it ready for Iray rendering... hold Ctrl to not change the existing texture maps. Glossiness and specular will need adjusting. I'm sure that many people like me who still use older pre-Iray props have saved their own tweaked Iray/Uber shader set-up for conversion. Older stuff will be labelled as "plastic" as their lighting model until converted for rendering in Iray. If you continue to use 3DL you can forget everything I just said.

nonesuch00

Diomede said:

The Chicago World's Fair of 1893 (World Columbian Exposition) was a watershed event.  It was a coming out party for Chicago and the American midwest and its spirit of growth, progress, new technologies, etc, etc, etc.

Like most fairs, there were prizes for flowers, livestock, cooking, etc, etc, etc.

One of those prizes was for the world's BEST beer.  The very best.  No etc, etc, etc.

The winner of the best beer at the 1893 World's fair was Pabst beer, a Milwaukee beer credited back to 1844, which is old in American Midwest time.  The prize was a blue ribbon.

Pabst Blue Ribbon (PBR), the world's best beer since 1844, recognized as such since 1893.

More details are provided by the knowledgeable folks at The Smithsonian Institution.  See

https://www.smithsonianmag.com/arts-culture/where-did-pabst-win-that-blue-ribbon-138975181/

.

First beer I ever drank, well popped open and took a hot drink of and spit out, found in the woods in 5th grade beside the school on the way to morning classes.