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BRDF please help!?!

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Hi there, I’m super sorry to bother but I was wondering if someone could maybe help me out with an answer?

As part of a project I’m to look into briefly what BRDF is and the difference/comparison it has with PBR texturing workflow. But after doing a bunch of research, all I seem to find is mathematical equations and that it’s actually part of PBR as well (along with the cook-Torrance workflow?). not exactly the answer I was expecting/looking for and was hoping if somebody could maybe shed some light for me and explain it in simpler terms - sorry if it seems like a dumb question. 

But basically what I want to know for now is can BRDF be considered a traditional texturing workflow? If so, how and why? How does it differ from PBR, or is it something (a function) like the first stage of texturing that was evolved into PBR? 

Are there other names for traditional and/or non-PBR texturing workflows? 

If anyone has any information it would be greatly appreciated and I’m so sorry if this whole paragraph came off seeming very uneducated, my mind is just fried at this point! 

I’m heading to bed so I probably won’t reply to anything until tomorrow :)

Replies

  • Alex_J
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    Alex_J veteran polycounter
    Physically-Based Rendering, And You Can Too! | Marmoset

    this is great article for PBR and explains what the problem is that PBR addresses. It's a good nutes and bolts guide for artist, covering just what you need to know to make 3d art.

    Right in the top it has link to more thorough, academic work and at the bottom some more references.
  • Abs2002
    Thank you for the reply, I've actually checked out this article before and the first one it links when I was looking for info on PBR - they're super helpful and infomative.

    But my main point to look ino right now is more specifically BRDF, I just don't know if there is a difference between that an PBR, I got the impression BRDF was a workflow that artists used before PBR became a thing, or more likely it evolved into PBR in a way I guess? But I could and probably am completely wrong so that's why I'm confused haha!!

    Sorry for the bother, thanks agian though :)
  • Noors
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    Noors greentooth
    Nope, BRDF is the complicated name for the equation(s) used for shading. Basically, given a surface and lights, it defines what color should be returned to the camera.
    Gouraud shading is the oldest and simpliest BRDF (edit:sorry i meant Lambert there. Gouraud shading is the vertex normal interpolation algo, not the actual lighting equation). Then we had Blinn/Phong. Then we had more physically realistic shading models with the concepts of energy conservation, metalness, anisotropy, image based/raytraced reflections... which are basically what makes "PBR" shaders now.
  • Dihemi
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    Dihemi polygon
    Abs2002 said:
    But my main point to look ino right now is more specifically BRDF, I just don't know if there is a difference between that an PBR, I got the impression BRDF was a workflow that artists used before PBR became a thing, or more likely it evolved into PBR in a way I guess? But I could and probably am completely wrong so that's why I'm confused haha!!
    PBR are render guidelines to assure that rendering looks the same across platforms that incorporate PBR workflows. BRDF on the other hand is an algorithm that calculates light. PBR render engines use the BRDF algorithm to calculate light.

    From PBR's wikipedia:
    "PBR topics that deal with surfaces often rely on a simplified model of the bidirectional reflectance distribution function (BRDF) that is quick to compute, and well approximates optical properties of the material using only handful of intuitive parameters."

    Source:
  • poopipe
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    poopipe high dynamic range
    As stated above brdf is an approximation of how light interacts with a surface and has cock all to do with pbr as a system beyond the fact you need one to shade a surface

    I feel that the question is set from a position of ignorance and you should ask for some clarity on what they are expecting you to answer
  • Abs2002
    Oh wow, thank you everyone for the replies, I wasn't expecting them to be as fast as they were, I really appreciate it! This 100% helps me out so I can't thank you enough for all of the information, definitely have a clearer understanding of what BRDF is now!!!

    I'm sorry if anyone felt that the question seemed a bit stupid, I just wasn't really understanding anything fully I was finding online since the equations really threw me off. I guess I had the impression previously that it was something it's not so it was hard to get that out of my head when researching, I apologize, I thought it would be simpler to ask artists on this forum before researching more.

    Also I don't really understand if I'm replying correctly or anything on here since I'm new sorry :/
    But thanks again for all the help!!!
  • Eric Chadwick
    To be fair, most questions are coming from a position of ignorance.  That's why they're being asked! So don't mind the jaded poopipe.

    I find pictures are a big help for artists to start to understand what a brdf is, and why it matters. Do an image search for "brdf lobes", look at images and start reading the associated papers. Then ask more questions, we're (actually!) happy to help.
  • poopipe
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    poopipe high dynamic range
    I didn't mean the OP, I meant whoever set the assignment 

    I am admittedly a miserable old bastard though 😁
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