Mtg 2/26: Thu-09-Jan-2025

Outline for Today

Getting Started

Administration

Today

  • Any questions or concerns from last day?
  • Question about software
  • Wiki scheduler
  • Chapter 1
  • Bunny

Summary

Summary

For Next Meeting

Wiki

Link to the UR Courses wiki page for this meeting

Media

Transcript

Audio Transcript

  • Go ahead. Welcome to meeting Two of 405-820-5805, The
  • Okay, I
  • me, that's the wrong course. Yes.
  • Anyone notice that before
  • ours is fine, yours is fine, four or five plus 805.
  • Yeah. I
  • Let's try refreshing it. 202510,
  • alright, so the attendance, like someone that's just, I just go
  • from the ER courses. I just
  • went through your courses. Yeah, yeah,
  • mental
  • illness just like personified.
  • I hope he loves his
  • craft. I
  • so I asked a question about the software I'm going to
  • so seven people have answered. I
  • so five people have said, Yes, one of them is our TA. Three
  • people said, not sure.
  • Do you have so, yeah, but
  • today, I so, yeah, I think
  • you have a Mac. So,
  • so I've had good, a positive Experience installing the
  • software on a mat I
  • so if You have c plus plus 17 available,
  • and They use C make For the configuration and
  • okay so I didn't say Happy Thursday. I
  • i went to ask this question about pbrt Because i
  • i One I'm talking with Science and Information Services about
  • options for making pprt Available on a lab computer and
  • so the idea is, is that You're not going to have,
  • have to have
  • a computer that can run this and
  • but it's
  • it's good to try. It's good. I
  • CS, so I don't know what options there are, so I just want to
  • encourage you to explore building the software on your
  • own computer
  • and if it doesn't work, we'll figure it out. Does that seem
  • okay?
  • Okay? Wiki scheduler. I
  • Good question.
  • Yes, can you put a link to your site on the your versus page for
  • those people that don't have it, guessing that you're putting a
  • lot of stuff on there, or some stuff on there, like the
  • pictures and
  • stuff? Yes, I
  • Yes, I will
  • add some more links. Thank you. So Laura is the only one who
  • signed up.
  • Thank you, Laura. You
  • so I'm just going to Talk about the quiz questions. Any other
  • questions that came up From our first Meeting?
  • Okay, I
  • one word, two processor or two steps
  • needed for literate programming. So literate programming is
  • maybe save file, Create a single file on that I'm
  • any suggestions about
  • what to call those two processes? I
  • Yeah, what is called Weaver. Yeah, so this is Weaver,
  • and this is the tangler i
  • Has anyone used latex for document processing?
  • It's quite, quite nice, I think. But it's, it's using, it's its
  • own example of literate programming. And
  • what do we need to simulate to create images that appear
  • real, real.
  • Thanks.
  • Yeah, light,
  • yeah, I
  • perspective
  • tell me more about perspective.
  • So having things get smaller, off into the distance, and to
  • make sure that everything appears to be like, you know,
  • things are in front of other things you don't see the thing
  • behind it, necessarily. To make sure everything is lined up in a
  • way that makes sense, doesn't cut through each other. Now,
  • still clipping.
  • Yeah. Okay. I
  • Who has The Minion?
  • Sorry notifications, I
  • you so it's important To have the physical models correct and
  • so a lot of the stuff we're going to deal with is about
  • Light and how to cap, how to model it,
  • and this is done within The context and
  • so we might have
  • different lenses on a camera, different effects.
  • So what is the last or second? Last Word say
  • correct Ways. Thank You. Do?
  • And then the third question was about how the color, the final
  • Color of a pixel, is determined in an image. I
  • A Z, buffer.
  • Said, buffer, yeah,
  • I used first pick.
  • So these Are screen based algorithms and
  • so they're focused on visibility.
  • And How do we decide the value we associate with
  • the different lighting, like specular lighting and stuff like
  • That or those are helpful.
  • Diffusion, yeah, the back trace of all rays of the light that
  • would enter that particular pixel and the color for each ray
  • i
  • Okay, So let's say I
  • so We follow a ray From the eye point and
  • through A pixel into The scene.
  • And So if We you
  • so
  • we send the ray out into the scene through the pixel and
  • and follow its interaction. We don't necessarily have a
  • complete model of all the interactions and
  • so some of the examples we looked at the other day had 1200
  • samples per pixel. I
  • can you squish this computer down?
  • Please? Thank you. You're
  • welcome.
  • I'm going to show a video that's mentioned in chapter one. This
  • is a Physically Based Rendering production system that
  • was done,
  • done by blue sky. Anyone familiar with the Ice Age
  • movies, this is the same people i
  • The projector is not on or not
  • this was nominated for an Oscar in 1998 The
  • CS, Thank You.
  • The skies as deep as you can Your
  • eyes, Won't You? Ground.
  • Five words you pronounce wrong two years before your
  • brain starts shutting down, dementia
  • is now known as type three
  • diabetes. I'm surprised you didn't get interrupted with the
  • math.
  • No, I decided to wait till the end.
  • So what did you think?
  • What kind of like claymation to a certain degree, kind of
  • reminded me of like puppets, almost like they're Aristotle.
  • So it's not i
  • It's not like we have to choose
  • between one or the other, so we can create different models and
  • Put them in environments
  • and
  • then just simulate The graphics, simulate the lighting.
  • Yeah, so I
  • it so the idea is, as we get
  • better information about different different aspects of
  • the physical world take better measurements, then we can
  • generate more accurate images. And so there are, there are
  • integrals that
  • can't be solved analytically, except for very simple cases,
  • but we're going to use numerical methods and the random sampling
  • algorithms to to realize images Based on those properties. And
  • All right, yeah, I was just reading the caption on the
  • picture
  • so I Does
  • that look like a Good photograph? Yeah?
  • Yeah. I
  • so we have some basic elements of ray tracing Here I
  • I align too many things there. Let's Try again. I
  • Let's Do
  • so we can change this around. So instead of the film in the
  • camera to the pinhole, you can put the eye at the pinhole
  • position and set up The image plane here and
  • so what is returned As the contribution or the Energy
  • collected along that Ray and
  • I shouldn't write so low on The board. Sorry,
  • there's only a problem in the core,
  • yeah, but it's the pen isn't working so well either. I
  • so when we send the ray out into the environment, we need to be
  • able to do the ray object intersections,
  • and so it's better, more quickly we can do that, the better it is
  • for the processing speed when we have 10s of billions of
  • triangles in a scene, we would like to deal only with the ones
  • that we really need to so there are acceleration structures that
  • are important to employ. So the light sources. So in 315 we
  • talked about point light sources, but they don't really
  • exist in the real world. So we have an area,
  • so it's
  • so there are different ways to model light sources and the
  • properties they have. So we're talking about the location of
  • lights and how they distribute their energy throughout space.
  • Visibility. I
  • so is the object visible from the light source so we can
  • spawn? Rays to check that visibility, light scattering at
  • surfaces.
  • So what kind of material is being so, how do we describe the
  • material
  • in the scene? I
  • it indirect light transport,
  • because light can arrive at a surface after bouncing off or
  • passing through other surfaces. So if we have glass,
  • if we bottled glass or the atmosphere and
  • here and how rays continue In space, Ray propagation i
  • I'll just say fig 1.2 so they've advertised the figures being
  • accessible and
  • add URLs, they don't work,
  • at least not The ones I've tried I
  • this is An example of one that doesn't work. I
  • work. So here's an example of visibility. So we have two light
  • sources, and it's surface is illuminated by or the point P is
  • illuminated by the one on The left, but not the one on The
  • right. So
  • so here we're looking, I
  • Looking at a bi directional I
  • so this
  • head is Using a sub surface scattering
  • so that means
  • light is scattered after It hits the surface and
  • so stop with this one. I think so here's a one we're seeing
  • here is based on the original algorithm by Turner with it in
  • 1980
  • so it has lots of mirrored surfaces, which which is the
  • forte of the ray tracing approach. And
  • those shadows are awfully deep considering how reflective those
  • spheres are.
  • So it's only looking at a few directions and
  • let's see what happens if we do stochastic, progressive photon
  • mapping. There we go.
  • So we can see that these are made of glass, and we can see
  • The light that's transmitted. And
  • here, here and here I'm
  • so in this case, the shadows are
  • solid.
  • Yeah, they're solid. So we're just testing whether, whether we
  • cast a shadow from the spheres above the plane and but here
  • we're using
  • The material properties. So let's Look where else changes
  • the
  • anyway,
  • we're out of time. Yeah,
  • so can you please look at getting the software installed
  • on your computer? And I put
  • on the wiki I have a
  • to link properly,
  • so I started a page for pbrt. So if you want, want to have a
  • discussion there or post your experience and you
  • and I will also add a class discussion
  • forum
  • so we can have
  • that discussion as well, and then, and then we'll take it
  • from there. So thank you very much for today. Have a great
  • weekend. We'll see you on Tuesday.

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