# Shading, lighting, & BRDF Theory. Cliff Lindsay, PHD

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Shading, lighting, & BRDF Theory Cliff Lindsay, PHD

2 Overview of today s lecture BRDF Characteristics Lights in terms of BRDFs Classes of BRDFs Ambient light & Shadows in terms of BRDFs

3 Decomposing Reflection Phong = Amb + Diff + Spec Don t Confuse Phong Shading

4 Refresher on lighting Diffuse component : idiff i=iamb+idiff+ispec Diffuse is Lambert s law: i diff nl Photons are scattered equally in all directions i diff ( nl) m diff s diff cos

5 Lighting Specular component : ispec Diffuse is dull (left) Specular: simulates a highlight

6 Specular component: Phong Phong specular highlight model Reflect l around n: r l 2(n l)n m shi m i ( r v) (cos ) shi spec ( n l) n r -l n l nl i spec mshi max(0,( r v) ) m spec s spec Read about Blinns highlight formula: (n. h) m

7 Ambient component: iamb Ad-hoc tries to account for light coming from other surfaces Just add a constant color: i amb m amb s amb

8 Lighting i=iamb+idiff+ispec + + = This is just a hack! Has little to do with how reality works!

9 What s lighting and what s shading? Lighting: the interaction between light and matter Shading: do lighting (at vertices) and determine pixel s colors from these Three types of shading: Flat, Goraud, and Phong

10 Now Some Info About Lights

11 Additions to the lighting equation Depends on distance: 1/(a+bt+ct ) Can have more lights: just sum their respective contributions Different light types: 2

12 Omni r l E L Lights pl pl I r r L 2 ps ps Directional Omni with falloff Spotlight

13 Falloff OpenGL way f dist s c s l 1 r s q r 2 Typical for Games f dist r r end end 1, r r 0 start,

14 Spotlights I L ( l) I L *( s 0 l) s exp S- angle P-penumbra U - cutoff

15 BRDF Theory Ratio between incoming and outgoing light Outgoing Incoming f ( l, v) Lo ( v) E( l)cos( ) i Think of f(l,v) as a function l v

16 BRDFs Better Modeling Better Modeling: Diffuse define better diffuse Specular different types of specular Ambient beyond just simple Phong ambient

17 What We ve Done Already For Phong Reflectance We calculate L o = f(l,v)*e(l)*cos( i ) Phong = i*mat+i*nl*mat+i*(nr) m *mat E(l) E(l) f(l,v) E(l) f(l,v) f ( l, v) Lo ( v) E( l)cos( ) i

18 BRDF Theory Generally Parameterized by: i - incoming o outgoing n Normal V View Vector L Light Vector Easy to param based on two quantities

19 BRDF Characteristics Helmholtz Reciprocity f ( l, v) f ( v, l) Conservation of Energy What comes in, must go? - Out - Absorbed - Scattered

20 Light Material Interaction When Light Hits Material: Interacts with surface Goes through surface an interacts below surface Independent of color (most of time for us) Sub-Surface Interaction Surface Interaction

21 Fresnel Reflectance Governs interface between two surfaces r i is the ideal reflection (look familiar?) t is the ideal refraction Snell s Law (n 1 sin( i ) = n 2 sin( t ) ) i = 90, glancing angle produces white color

22 Fresnel Example

23 Which Would You Drink?

24 Subsurface Scattering Very Important for flesh Most organic materials exhibit Lots of other materials too Without With

25 Micro-Geometry

26 Micro-geometry A. Self Shadowing B. Masking C. Interreflection (self) A B C

27 Example: Micro-Geometry Retro-Reflection

28 Micro-facet Special Case Micro-geometry Facets Assumed to be ideal mirrors Uses Half-vector h (half-way vector) NDF: Normal Distribution Function p(h) Introduces Geometry Factor G(l,v)

29 Micro-facet Incorporates: NDF distribution of facets on surface Geometry surface geometry Fresnel f ( l, v) p( h) G( l, v) Rf ( h) 4k cos( )cos( ) p i o

30 Example BRDFs Modified Phong Old Phong Physically Accurate Phong mat f ( l, v) mat f ( l, v) mat *cos( r ) cos( i ) 0 mat *cos( r ) m m,,

31 Simple Visibility Many BRDFs (especially game ones) have no visibility term at all This means the visibility term = 1 Implies geometry factor = nl * nv.

32 Torrance Sparrow Geometry invented by Blinn in 1975 as a reformulation of the Torrance- Sparrow based on an micro-geometry model not affected by roughness

33 More Geometry Factors Kelemen-Szirmay-Kalos Geometry Factor Has cheap and effective approximation

34 Rougher = Blurrier

35 Smith Geometry Factor Gsmith cos i cos (1 k) i k cos o cos (1 k) o k Incorporates roughness into Geometry Term k=(2m 2 /) Roughness

36 Many Different Things To Consider

37 Samples from real-world materials

38 Demo

39 More Geometry Factor Phong Ambient Ambient Occlusion AO + GI Light Instead of general inclusion within the BRDF We can account for geometry for each geometry specifically

40 Ambient Occlusion At surface points P shoot out rays If we hit something shelf-shadow If not, calculate lighting (NL) or something Incorporate into reflectance function

41 AO Light = local hemisphere Centered at current surface point Radius = user parameter Can be rendered with ray tracing Gives perceptual clues of depth, curvature and spatial proximity Lots of techniques (For Games: Screen Space, Horizon-Based, Image-Space)

42 Example

43 Other Illumination Models Cliff Lindsay

44 Overview of today s lecture Refresher on simple lighting models Plus some new stuff More Advanced Illumination Models

45 Additions to the lighting equation Depends on distance: 1/(a+bt+ct ) Can have more lights: just sum their respective contributions Different light types: 2

46 What s lighting and what s shading? Lighting: the interaction between light and matter Shading: do lighting (at vertices) and determine pixel s colors from these Three types of shading: Flat, Goraud, and Phong

47 Global Models You have seen: Local illumination model: Phong Ambient Diffuse Specular Point light sources No: shadows, inter-object light reflection. More global illumination model: Ray Tracing Shadows Area light sources (via distributed ray tracing) inter-object light reflection Tradeoffs: Improvements in fidelity come at the expense of computational complexity.

48 Realistic rendering For each visible point p in the scene How much light is reflected towards the camera

49 Direct + Indirect p

50 Local vs. Global

51 Indirect Light Direct-only 1-bounce indirect 2-bounce indirect

52 Ray Tracing

53 Different Ways to Achieve GI Ray Tracing Path Tracing Photon Mapping Radiosity Metropolis Light Transport

54 Put it all together

### CSE 681 Illumination and Phong Shading

CSE 681 Illumination and Phong Shading Physics tells us What is Light? We don t see objects, we see light reflected off of objects Light is a particle and a wave The frequency of light What is Color? Our

### A Brief Overview of. Global Illumination. Thomas Larsson, Afshin Ameri Mälardalen University

A Brief Overview of Global Illumination Thomas Larsson, Afshin Ameri Mälardalen University 1 What is Global illumination? Global illumination is a general name for realistic rendering algorithms Global

### Illumination. Illumination CMSC 435/634

Illumination CMSC 435/634 Illumination Interpolation Illumination Illumination Interpolation Illumination Illumination Effect of light on objects Mostly look just at intensity Apply to each color channel

### Global Illumination. COMP 575/770 Spring 2013

Global Illumination COMP 575/770 Spring 2013 Final Exam and Projects COMP 575 Final Exam Friday, May 3 4:00 pm COMP 770 (and 575 extra credit) Projects Final report due by end of day, May 1 Presentations:

### Topic 9: Lighting & Reflection models 9/10/2016. Spot the differences. Terminology. Two Components of Illumination. Ambient Light Source

Topic 9: Lighting & Reflection models Lighting & reflection The Phong reflection model diffuse component ambient component specular component Spot the differences Terminology Illumination The transport

### Background: Physics and Math of Shading

Background: Physics and Math of Shading Naty Hoffman 2K Hi. Over the next 25 minutes or so I ll be going from the physics underlying shading, to the math used to describe it in the kind of shading models

### Ray Tracing. CSCI 420 Computer Graphics Lecture 15. Ray Casting Shadow Rays Reflection and Transmission [Ch ]

CSCI 420 Computer Graphics Lecture 15 Ray Tracing Ray Casting Shadow Rays Reflection and Transmission [Ch. 13.2-13.3] Jernej Barbic University of Southern California 1 Local Illumination Object illuminations

Illumination and Shading Computer Graphics COMP 770 (236) Spring 2007 Instructor: Brandon Lloyd 2/14/07 1 From last time Texture mapping overview notation wrapping Perspective-correct interpolation Texture

### CPSC 314 LIGHTING AND SHADING

CPSC 314 LIGHTING AND SHADING UGRAD.CS.UBC.CA/~CS314 slide credits: Mikhail Bessmeltsev et al 1 THE RENDERING PIPELINE Vertices and attributes Vertex Shader Modelview transform Per-vertex attributes Vertex

### CS 5625 Lec 2: Shading Models

CS 5625 Lec 2: Shading Models Kavita Bala Spring 2013 Shading Models Chapter 7 Next few weeks Textures Graphics Pipeline Light Emission To compute images What are the light sources? Light Propagation Fog/Clear?

### 03 RENDERING PART TWO

03 RENDERING PART TWO WHAT WE HAVE SO FAR: GEOMETRY AFTER TRANSFORMATION AND SOME BASIC CLIPPING / CULLING TEXTURES AND MAPPING MATERIAL VISUALLY DISTINGUISHES 2 OBJECTS WITH IDENTICAL GEOMETRY FOR NOW,

### Lighting and Shading. Slides: Tamar Shinar, Victor Zordon

Lighting and Shading Slides: Tamar Shinar, Victor Zordon Why we need shading Suppose we build a model of a sphere using many polygons and color each the same color. We get something like But we want 2

### ECS 175 COMPUTER GRAPHICS. Ken Joy.! Winter 2014

ECS 175 COMPUTER GRAPHICS Ken Joy Winter 2014 Shading To be able to model shading, we simplify Uniform Media no scattering of light Opaque Objects No Interreflection Point Light Sources RGB Color (eliminating

Computer Graphics (Fall 2008) COMS 4160, Lecture 19: Illumination and Shading 2 http://www.cs.columbia.edu/~cs4160 Radiance Power per unit projected area perpendicular to the ray per unit solid angle in

### Comp 410/510 Computer Graphics. Spring Shading

Comp 410/510 Computer Graphics Spring 2017 Shading Why we need shading Suppose we build a model of a sphere using many polygons and then color it using a fixed color. We get something like But we rather

### Lighting affects appearance

Lighting affects appearance 1 Source emits photons Light And then some reach the eye/camera. Photons travel in a straight line When they hit an object they: bounce off in a new direction or are absorbed

### Lecture 4: Reflection Models

Lecture 4: Reflection Models CS 660, Spring 009 Kavita Bala Computer Science Cornell University Outline Light sources Light source characteristics Types of sources Light reflection Physics-based models

### Computer Graphics. Illumination and Shading

() Illumination and Shading Dr. Ayman Eldeib Lighting So given a 3-D triangle and a 3-D viewpoint, we can set the right pixels But what color should those pixels be? If we re attempting to create a realistic

### Lighting and Shading Computer Graphics I Lecture 7. Light Sources Phong Illumination Model Normal Vectors [Angel, Ch

15-462 Computer Graphics I Lecture 7 Lighting and Shading February 12, 2002 Frank Pfenning Carnegie Mellon University http://www.cs.cmu.edu/~fp/courses/graphics/ Light Sources Phong Illumination Model

### CSE 167: Lecture #7: Color and Shading. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011

CSE 167: Introduction to Computer Graphics Lecture #7: Color and Shading Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011 Announcements Homework project #3 due this Friday,

### Computer Graphics. Lecture 13. Global Illumination 1: Ray Tracing and Radiosity. Taku Komura

Computer Graphics Lecture 13 Global Illumination 1: Ray Tracing and Radiosity Taku Komura 1 Rendering techniques Can be classified as Local Illumination techniques Global Illumination techniques Local

### CS5620 Intro to Computer Graphics

So Far wireframe hidden surfaces Next step 1 2 Light! Need to understand: How lighting works Types of lights Types of surfaces How shading works Shading algorithms What s Missing? Lighting vs. Shading

### Global Illumination. Global Illumination. Direct Illumination vs. Global Illumination. Indirect Illumination. Soft Shadows.

CSCI 480 Computer Graphics Lecture 18 Global Illumination BRDFs Raytracing and Radiosity Subsurface Scattering Photon Mapping [Ch. 13.4-13.5] March 28, 2012 Jernej Barbic University of Southern California

### Rendering Algorithms: Real-time indirect illumination. Spring 2010 Matthias Zwicker

Rendering Algorithms: Real-time indirect illumination Spring 2010 Matthias Zwicker Today Real-time indirect illumination Ray tracing vs. Rasterization Screen space techniques Visibility & shadows Instant

### CENG 477 Introduction to Computer Graphics. Ray Tracing: Shading

CENG 477 Introduction to Computer Graphics Ray Tracing: Shading Last Week Until now we learned: How to create the primary rays from the given camera and image plane parameters How to intersect these rays

### Rendering Light Reflection Models

Rendering Light Reflection Models Visual Imaging in the Electronic Age Donald P. Greenberg October 3, 2017 Lecture #13 Program of Computer Graphics, Cornell University General Electric - 167 Cornell in

### Computer Graphics. Lecture 10. Global Illumination 1: Ray Tracing and Radiosity. Taku Komura 12/03/15

Computer Graphics Lecture 10 Global Illumination 1: Ray Tracing and Radiosity Taku Komura 1 Rendering techniques Can be classified as Local Illumination techniques Global Illumination techniques Local

### Photorealism: Ray Tracing

Photorealism: Ray Tracing Reading Assignment: Chapter 13 Local vs. Global Illumination Local Illumination depends on local object and light sources only Global Illumination at a point can depend on any

### Raytracing CS148 AS3. Due :59pm PDT

Raytracing CS148 AS3 Due 2010-07-25 11:59pm PDT We start our exploration of Rendering - the process of converting a high-level object-based description of scene into an image. We will do this by building

### Lecture 22: Basic Image Formation CAP 5415

Lecture 22: Basic Image Formation CAP 5415 Today We've talked about the geometry of scenes and how that affects the image We haven't talked about light yet Today, we will talk about image formation and

### Lecture 7 - Path Tracing

INFOMAGR Advanced Graphics Jacco Bikker - November 2016 - February 2017 Lecture 7 - I x, x = g(x, x ) ε x, x + S ρ x, x, x I x, x dx Welcome! Today s Agenda: Introduction Advanced Graphics 3 Introduction

### rendering equation computer graphics rendering equation 2009 fabio pellacini 1

rendering equation computer graphics rendering equation 2009 fabio pellacini 1 physically-based rendering synthesis algorithms that compute images by simulation the physical behavior of light computer

### Lecture 18: Primer on Ray Tracing Techniques

Lecture 18: Primer on Ray Tracing Techniques 6.172: Performance Engineering of Software Systems Joshua Slocum November 16, 2010 A Little Background Image rendering technique Simulate rays of light - ray

### Lighting affects appearance

Lighting affects appearance 1 Source emits photons Light And then some reach the eye/camera. Photons travel in a straight line When they hit an object they: bounce off in a new direction or are absorbed

Shading and Illumination OpenGL Shading Without Shading With Shading Physics Bidirectional Reflectance Distribution Function (BRDF) f r (ω i,ω ) = dl(ω ) L(ω i )cosθ i dω i = dl(ω ) L(ω i )( ω i n)dω

### EDAN30 Photorealistic Computer Graphics. Seminar 1, Whitted Ray Tracing (And then some!) Magnus Andersson, PhD student

EDAN30 Photorealistic Computer Graphics Seminar, 203 Whitted Ray Tracing (And then some!) Magnus Andersson, PhD student (magnusa@cs.lth.se) Today s Agenda Structure of Assignments Quick prtracer walkthrough

### Radiometry & BRDFs CS295, Spring 2017 Shuang Zhao

Radiometry & BRDFs CS295, Spring 2017 Shuang Zhao Computer Science Department University of California, Irvine CS295, Spring 2017 Shuang Zhao 1 Today s Lecture Radiometry Physics of light BRDFs How materials

### Lets assume each object has a defined colour. Hence our illumination model is looks unrealistic.

Shading Models There are two main types of rendering that we cover, polygon rendering ray tracing Polygon rendering is used to apply illumination models to polygons, whereas ray tracing applies to arbitrary

Illumination & Shading Goals Introduce the types of light-material interactions Build a simple reflection model---the Phong model--- that can be used with real time graphics hardware Why we need Illumination

CS 543: Computer Graphics Illumination & Shading I Robert W. Lindeman Associate Professor Interactive Media & Game Development Department of Computer Science Worcester Polytechnic Institute gogo@wpi.edu

### Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering. Brent Burley Walt Disney Animation Studios

The 42nd International Conference and Exhibition on Computer Graphics and Interactive Techniques Extending the Disney BRDF to a BSDF with Integrated Subsurface Scattering Brent Burley Walt Disney Animation

### Surface Reflection Models

Surface Reflection Models Frank Losasso (flosasso@nvidia.com) Introduction One of the fundamental topics in lighting is how the light interacts with the environment. The academic community has researched

### Interpolation using scanline algorithm

Interpolation using scanline algorithm Idea: Exploit knowledge about already computed color values. Traverse projected triangle top-down using scanline. Compute start and end color value of each pixel

### Ø Sampling Theory" Ø Fourier Analysis Ø Anti-aliasing Ø Supersampling Strategies" Ø The Hall illumination model. Ø Original ray tracing paper

CS 431/636 Advanced Rendering Techniques Ø Dr. David Breen Ø Korman 105D Ø Wednesday 6PM 8:50PM Presentation 6 5/16/12 Questions from ast Time? Ø Sampling Theory" Ø Fourier Analysis Ø Anti-aliasing Ø Supersampling

### Turn on the Lights: Reflectance

Turn on the Lights: Reflectance Part 2: Shading Tuesday, October 15 2012 Lecture #14 Goal of Shading Model simple light sources Point light sources Extended light sources Ambient lighting Model lighting

### Review for Ray-tracing Algorithm and Hardware

Review for Ray-tracing Algorithm and Hardware Reporter: 邱敬捷博士候選人 Lan-Da Van ( 范倫達 ), Ph. D. Department of Computer Science National Chiao Tung University Taiwan, R.O.C. Summer, 2017 1 2017/7/26 Outline

### Background: Physics and Math of Shading

Background: Physics and Math of Shading by Naty Hoffman In this section of the course notes, we will go over the fundamentals behind physically based shading models, starting with a qualitative description

### Announcements. Written Assignment 2 out (due March 8) Computer Graphics

Announcements Written Assignment 2 out (due March 8) 1 Advanced Ray Tracing (Recursive) Ray Tracing Antialiasing Motion Blur Distribution Ray Tracing Ray Tracing and Radiosity Assumptions Simple shading

### MR Shaders Dielectric Materials Rendering Glass and Simple Caustics

Dielectric Material This shader is a physically based material shader that can be used to simulate dielectric media such as glass, water, and other liquids. The shader uses Fresnel's formulas for dielectric

### The Rasterization Pipeline

Lecture 5: The Rasterization Pipeline Computer Graphics and Imaging UC Berkeley CS184/284A, Spring 2016 What We ve Covered So Far z x y z x y (0, 0) (w, h) Position objects and the camera in the world

### Orthogonal Projection Matrices. Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

Orthogonal Projection Matrices 1 Objectives Derive the projection matrices used for standard orthogonal projections Introduce oblique projections Introduce projection normalization 2 Normalization Rather

### So far, we have considered only local models of illumination; they only account for incident light coming directly from the light sources.

11 11.1 Basics So far, we have considered only local models of illumination; they only account for incident light coming directly from the light sources. Global models include incident light that arrives

### Precomputed Radiance Transfer: Theory and Practice

1 Precomputed Radiance Transfer: Peter-Pike Sloan Microsoft Jaakko Lehtinen Helsinki Univ. of Techn. & Remedy Entertainment Jan Kautz MIT 2 Introduction Jan Kautz MIT 3 Introduction We see here an example

### Computergrafik. Matthias Zwicker Universität Bern Herbst 2016

Computergrafik Matthias Zwicker Universität Bern Herbst 2016 Today More shading Environment maps Reflection mapping Irradiance environment maps Ambient occlusion Reflection and refraction Toon shading

DH2323 DGI15 INTRODUCTION TO COMPUTER GRAPHICS AND INTERACTION LIGHTING AND SHADING Christopher Peters HPCViz, KTH Royal Institute of Technology, Sweden chpeters@kth.se http://kth.academia.edu/christopheredwardpeters

### The Rasterization Pipeline

Lecture 5: The Rasterization Pipeline Computer Graphics and Imaging UC Berkeley What We ve Covered So Far z x y z x y (0, 0) (w, h) Position objects and the camera in the world Compute position of objects

### Background: Physics and Math of Shading

Background: Physics and Math of Shading by Naty Hoffman In this section of the course notes, we will go over the fundamentals behind physically based shading models, starting with a qualitative description

### Chapter 23- UV Texture Mapping

Chapter 23- UV Texture Mapping Since games need to be able to process operations as fast as possible, traditional rendering techniques (specular, ray tracing reflections and refractions) cannot typically

### Fundamentals of Rendering - Reflectance Functions

Fundamentals of Rendering - Reflectance Functions Image Synthesis Torsten Möller Mike Phillips Reading Chapter 8 of Physically Based Rendering by Pharr&Humphreys Chapter 16 in Foley, van Dam et al. Chapter

### CMSC427 Advanced shading getting global illumination by local methods. Credit: slides Prof. Zwicker

CMSC427 Advanced shading getting global illumination by local methods Credit: slides Prof. Zwicker Topics Shadows Environment maps Reflection mapping Irradiance environment maps Ambient occlusion Reflection

### CSE 167: Lecture #8: GLSL. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2012

CSE 167: Introduction to Computer Graphics Lecture #8: GLSL Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2012 Announcements Homework project #4 due Friday, November 2 nd Introduction:

### Photon Mapping. Michael Doggett Department of Computer Science Lund university

Photon Mapping Michael Doggett Department of Computer Science Lund university Outline Photon Mapping (ch. 14 in textbook) Progressive Stochastic 2011 Michael Doggett How to make light sampling faster?

### Light: Geometric Optics (Chapter 23)

Light: Geometric Optics (Chapter 23) Units of Chapter 23 The Ray Model of Light Reflection; Image Formed by a Plane Mirror Formation of Images by Spherical Index of Refraction Refraction: Snell s Law 1

### Here I ll present a brief summary of the important aspects and then dive into improvements we made on Black Ops II.

We started pursuing Physically Based Shading during Black Ops, details of which I presented at SIGGRAPH 2011, as part of the Advances in Real-Time Rendering course. Here I ll present a brief summary of

### Color and Light. CSCI 4229/5229 Computer Graphics Summer 2008

Color and Light CSCI 4229/5229 Computer Graphics Summer 2008 Solar Spectrum Human Trichromatic Color Perception Are A and B the same? Color perception is relative Transmission,Absorption&Reflection Light

### Light: Geometric Optics

Light: Geometric Optics 23.1 The Ray Model of Light Light very often travels in straight lines. We represent light using rays, which are straight lines emanating from an object. This is an idealization,

### Classic Rendering Pipeline

CS580: Classic Rendering Pipeline Sung-Eui Yoon ( 윤성의 ) Course URL: http://sglab.kaist.ac.kr/~sungeui/gcg/ Course Objectives Understand classic rendering pipeline Just high-level concepts, not all the

Global Illumination and Radiosity CS434 Daniel G. Aliaga Department of Computer Science Purdue University Recall: Lighting and Shading Light sources Point light Models an omnidirectional light source (e.g.,

### CSE 167: Lecture #8: Lighting. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011

CSE 167: Introduction to Computer Graphics Lecture #8: Lighting Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011 Announcements Homework project #4 due Friday, October 28 Introduction:

### CEng 477 Introduction to Computer Graphics Fall

Illumination Models and Surface-Rendering Methods CEng 477 Introduction to Computer Graphics Fall 2007 2008 Illumination Models and Surface Rendering Methods In order to achieve realism in computer generated

Illumination and Shading Illumination (Lighting)! Model the interaction of light with surface points to determine their final color and brightness! The illumination can be computed either at vertices or

### Light Sources. Spotlight model

lecture 12 Light Sources sunlight (parallel) Sunny day model : "point source at infinity" - lighting - materials: diffuse, specular, ambient spotlight - shading: Flat vs. Gouraud vs Phong light bulb ambient

### IBL/GI & GLASS. Getting Realistic Results By Yon Resch. The Three Types of GI lighting and Glass

IBL/GI & GLASS Getting Realistic Results By Yon Resch Glass and other transparent materials are some of the hardest materials to render realistically. This has mainly to do with the number of additional

### Fundamentals of Rendering - Reflectance Functions

Fundamentals of Rendering - Reflectance Functions CMPT 461/761 Image Synthesis Torsten Möller Reading Chapter 8 of Physically Based Rendering by Pharr&Humphreys Chapter 16 in Foley, van Dam et al. Chapter

### SAMPLING AND NOISE. Increasing the number of samples per pixel gives an anti-aliased image which better represents the actual scene.

SAMPLING AND NOISE When generating an image, Mantra must determine a color value for each pixel by examining the scene behind the image plane. Mantra achieves this by sending out a number of rays from

### Computer Graphics. Shading. Based on slides by Dianna Xu, Bryn Mawr College

Computer Graphics Shading Based on slides by Dianna Xu, Bryn Mawr College Image Synthesis and Shading Perception of 3D Objects Displays almost always 2 dimensional. Depth cues needed to restore the third

### Lights and Lighting. Lecture overview. Light 2/3/2013. Digital Lighting and Rendering CGT 340

Lights and Lighting Digital Lighting and Rendering CGT 340 Lighting is 5% of light setup and 95% of revisions and adjustments. Jeremy Birn Lecture overview What is light? Spectrum Typical cases Metamers

### Recent Advances in Monte Carlo Offline Rendering

CS294-13: Special Topics Lecture #6 Advanced Computer Graphics University of California, Berkeley Monday, 21 September 2009 Recent Advances in Monte Carlo Offline Rendering Lecture #6: Monday, 21 September

### Geometrical Optics. Name ID TA. Partners. Date Section. Please do not scratch, polish or touch the surface of the mirror.

Geometrical Optics Name ID TA Partners Date Section Please do not scratch, polish or touch the surface of the mirror. 1. Application of geometrical optics: 2. Real and virtual images: One easy method to

Lessons Learned from HW Shading CS Interactive Computer Graphics Prof. David E. Breen Department of Computer Science Only have an idle() function if something is animated Set idle function to NULL, when

### surface: reflectance transparency, opacity, translucency orientation illumination: location intensity wavelength point-source, diffuse source

walters@buffalo.edu CSE 480/580 Lecture 18 Slide 1 Illumination and Shading Light reflected from nonluminous objects depends on: surface: reflectance transparency, opacity, translucency orientation illumination:

### Light. Form of Electromagnetic Energy Only part of Electromagnetic Spectrum that we can really see

Light Form of Electromagnetic Energy Only part of Electromagnetic Spectrum that we can really see Facts About Light The speed of light, c, is constant in a vacuum. Light can be: REFLECTED ABSORBED REFRACTED

### Property of: Entrada Interactive. PBR Workflow. Working within a PBR-based environment

Property of: Entrada Interactive PBR Workflow Working within a PBR-based environment Ryan Manning 8/24/2014 MISCREATED PBR WORKFLOW CryDocs on Physically Based Shading/Rendering: http://docs.cryengine.com/display/sdkdoc4/physically+based+rendering

### 2/1/10. Outline. The Radiance Equation. Light: Flux Equilibrium. Light: Radiant Power. Light: Equation. Radiance. Jan Kautz

Outline Jan Kautz Basic terms in radiometry Radiance Reflectance The operator form of the radiance equation Meaning of the operator form Approximations to the radiance equation 2005 Mel Slater, 2006 Céline

Last Time? The Traditional Graphics Pipeline Reading for Today A Practical Model for Subsurface Light Transport, Jensen, Marschner, Levoy, & Hanrahan, SIGGRAPH 2001 Participating Media Measuring BRDFs

### CS4670/5760: Computer Vision Kavita Bala Scott Wehrwein. Lecture 23: Photometric Stereo

CS4670/5760: Computer Vision Kavita Bala Scott Wehrwein Lecture 23: Photometric Stereo Announcements PA3 Artifact due tonight PA3 Demos Thursday Signups close at 4:30 today No lecture on Friday Last Time:

### Chapter 9- Ray-Tracing

Ray-tracing is used to produce mirrored and reflective surfaces. It is also being used to create transparency and refraction (bending of images through transparent surfaceslike a magnifying glass or a

### Chapter 11 Global Illumination. Part 1 Ray Tracing. Reading: Angel s Interactive Computer Graphics (6 th ed.) Sections 11.1, 11.2, 11.

Chapter 11 Global Illumination Part 1 Ray Tracing Reading: Angel s Interactive Computer Graphics (6 th ed.) Sections 11.1, 11.2, 11.3 CG(U), Chap.11 Part 1:Ray Tracing 1 Can pipeline graphics renders images

### Wednesday, 26 January 2005, 14:OO - 17:OO h.

Delft University of Technology Faculty Electrical Engineering, Mathematics, and Computer Science Mekelweg 4, Delft TU Delft Examination for Course IN41 5 1-3D Computer Graphics and Virtual Reality Please

### Shading , Fall 2004 Nancy Pollard Mark Tomczak

15-462, Fall 2004 Nancy Pollard Mark Tomczak Shading Shading Concepts Shading Equations Lambertian, Gouraud shading Phong Illumination Model Non-photorealistic rendering [Shirly, Ch. 8] Announcements Written

### Single Scattering in Refractive Media with Triangle Mesh Boundaries

Single Scattering in Refractive Media with Triangle Mesh Boundaries Bruce Walter Shuang Zhao Nicolas Holzschuch Kavita Bala Cornell Univ. Cornell Univ. Grenoble Univ. Cornell Univ. Presented at SIGGRAPH

### Three-Dimensional Graphics V. Guoying Zhao 1 / 55

Computer Graphics Three-Dimensional Graphics V Guoying Zhao 1 / 55 Shading Guoying Zhao 2 / 55 Objectives Learn to shade objects so their images appear three-dimensional Introduce the types of light-material

### Illumination Models and Surface-Rendering Methods. Chapter 10

Illumination Models and Surface-Rendering Methods Chapter 10 Illumination and Surface- Rendering Given scene specifications object positions, optical properties of the surface, viewer position, viewing

### Interactive Light Mapping with PowerVR Ray Tracing

Interactive Light Mapping with PowerVR Ray Tracing Jens Fursund Justin DeCell Light Map Basics A light map is a texture that stores lighting for objects in the scene 3 Generation of light maps for GI Charting

### Materials & Shadows. Steve Rotenberg CSE168: Rendering Algorithms UCSD, Winter 2017

Materials & Shadows Steve Rotenberg CSE168: Rendering Algorithms UCSD, Winter 2017 Diffuse Surfaces In an earlier lecture, we discussed diffuse surfaces We looked at the idealized Lambertian diffuse case

### PHY 112: Light, Color and Vision. Lecture 11. Prof. Clark McGrew Physics D 134. Review for Exam. Lecture 11 PHY 112 Lecture 1

PHY 112: Light, Color and Vision Lecture 11 Prof. Clark McGrew Physics D 134 Review for Exam Lecture 11 PHY 112 Lecture 1 From Last Time Lenses Ray tracing a Convex Lens Announcements The midterm is Thursday

### Computer Graphics 1. Chapter 7 (June 17th, 2010, 2-4pm): Shading and rendering. LMU München Medieninformatik Andreas Butz Computergraphik 1 SS2010

Computer Graphics 1 Chapter 7 (June 17th, 2010, 2-4pm): Shading and rendering 1 The 3D rendering pipeline (our version for this class) 3D models in model coordinates 3D models in world coordinates 2D Polygons