Advanced Graphics

Universiteit Utrecht - Information and Computing Sciences

academic year 2022/23 – 2nd block

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News (Archive)	Schedule	Downloads	Grading
Format & Organization	Lecture Slides	Practicals	Literature & Links

News

Format and Organization

Overview

The master course Advanced Graphics addresses advanced topics in 3D computer graphics. The focus of the course is Physically-based rendering of 3D scenes. The course has two main focus areas: Rendering Algorithms and Making Rendering More Efficient. Efficiency will be sought through Acceleration Structure Construction and Traversal and Variance Reduction (rather than low level optimization).

The course starts with a recap of Whitted-style ray tracing. We then explore various acceleration structures that help to run the ray tracing algorithm in real-time on commodity hardware. We will see that a well-built Bounding Volume Hierarchy provides both flexibility and speed, for static and dynamic scenes.

The second part of the course introduces the path tracing algorithm, and related light transport theory. We investigate various methods to improve the efficiency of the algorithm using probability theory. We will see that efficient path tracing can yield interactive frame rates.

In the third part of the course we use GPGPU to run ray tracing and path tracing on the GPU. We will explore recent research in high performance stochastic rendering.

Course objectives

At the end of this course you will have detailed knowledge about the following topics:

physical light transport, and how to simulate this behavior in a computer program;
modern ray tracing based rendering algorithms;
high level optimizations of the ray tracing algorithm;
Monte Carlo integration and variance reduction;
GPU-specific optimizations of ray tracing algorithms.

You will have practical experience in the following topics:

implementation of Whitted-style ray tracing and path tracing;
implementation of acceleration structure construction and traversal.

You will have a reasonable grasp of several related topics:

distributed ray tracing;
bidirectional methods, including photon mapping;
filtering of the noisy output of a path tracer;
RTX, OptiX, Embree and RadeonRays;
SIMD and ray packet traversal.

LINKS

Teams: this is where you will find 'non-static' content.
Osiris: the official (centrally managed) schedule.
www.cs.uu.nl: uniform course information.
Join us on Teams for support and collaboration.

PEOPLE

Lecturer: Jacco Bikker (j.bikker@uu.nl)

LectureS

Lectures and labs conveniently are spread all over the campus.
Two lectures per week: Tuesday 10:00 - 11:45, Thursday 13:15 - 15:00.
Two lecturer-supervised labs per week: Tuesday 9:00 - 10:00, Thursday 15:15 - 17:00.

Lectures will be recorded for those that cannot be physically on campus, and for later reference.

Practicals

This course has a practical project track. During this course, you will develop an interactive renderer. You may work on the project alone, or with one other student. The practical project has three milestones. The second and third milestones build on the previous one: the outcome is a full ray tracer, which makes a great addition to your portfolio.

Final Exam

There will be one exam at the end of the block (i.e., no mid-term exam). A retake exam or retake assignment can be used to compensate some deficits (see grading section for details).

Prerequisites

Basic knowledge in linear algebra, calculus and probability theory, as required for the masters program. See "Elementary maths for GMT".
Fundamentals in algorithms and data structures.
Bachelor level knowledge in computer graphics is strongly recommended. Without prior graphics knowledge, you will need substantial additional time (and probably some talent).
Good programming skills; C# and C++ will both work, but for optimal performance and certain low level aspects, C++ is recommended. Plan for additional time if you plan to familiarize yourself with C++ during the course.
Good to have, but not absolutely required: basic experience with graphics programming (e.g. OpenGL / DirectX / Vulkan). Note that we will not use an API for the assignments; we'll build our own.

Topics

Ray Tracing

Whitted-style Ray Tracing

Recap
Beer's Law, Fresnel

Acceleration Structures

Octree, kD-tree, BSP
Bounding Volume Hierarchy
Efficient Construction & Traversal

Dynamic Scenes

The Top-Level BVH

Real-time

Ray Packet Traversal

Path Tracing

Light Transport

The Rendering Equation

Monte-Carlo Algorithms

Distributed Ray Tracing
Path Tracing

Variance Reduction

Stratification
Importance Sampling
Next Event Estimation

Interactive

Multi-branching BVHs

Efficiency

GPU implementations

Streaming Algorithms
Wavefront Path Tracing

Variance reduction

Multiple Importance Sampling
Resampled Importance Sampling
Bi-directional Path Tracing
Photon Mapping

Image Postprocessing

Bias
Filtering Techniques

Schedule

BLOCK 2 Schedule

Week	Date	Lecture / Exams	Working College	Practical #1	Practical #2	Practical #3
46	Tue Nov 15 10:00-11:45	NO LECTURE
46	Thu Nov 17 13:15-15:00	Lecture 1 Introduction
47	Tue Nov 22 in PORTA 0.16 10:00-11:45	Lecture 2 Whitted Ray Tracing	Working College Tue 9:00-10:00	Assignment 1 Basic framework
47	Thu Nov 24 in DDW-1.22 13:15-17:00	Lecture 3 Light Transport / intro	Working College Thu 15:15-17:00
48	Tue Dec 29 in BOL 1.022 10:00-11:45	Lecture 4 Path Tracing	Working College Tue 9:00-10:00
48	Thu Dec 1 in DDW-1.30 13:15-17:00	Lecture 5 Acceleration Structures/ intro	Working College Thu 15:15-17:00
49	Tue Dec 6 in BBG-201 09:15-10:45 (!!)	Lecture 6 Perfect BVHs / future work		Deadline: Wednesday Dec 7, 17:00	Assignment 2: Acceleration structures or: Path Tracing
49	Thu Dec 8 in DDW-1.30 13:15-17:00	Lecture 7 GPU Ray Tracing (1)
50	Tue Dec 13 in BBG-201 09:15-10:45 (!!)	Lecture 8 Variance Reduction (1)	Working College Tue 9:00-10:00
50	Thu Dec 15 in BBG-1.61 13:15-17:00	Lecture 9 Variance Reduction (2)	Working College Thu 15:15-17:00
51	Tue Dec 20 in BBG-0.83 10:00-11:45	~~Lecture 10~~ ~~GPU Ray Tracing (2)~~	Working College ~~Tue 9:00-10:00~~			Assignment 3: Specialize
51	Thu Dec 22 13:15-17:00	NO LECTURE			Deadline: Fri Dec 23, 17:00h
52,1	Christmas, New Year, Holidays
2	Tue Jan 10 in PORTA 0.16 10:00-11:45	Lecture 10 GPGPU (2), P3 topics	Working College Tue 9:00-10:00
2	Thu Jan 12 in PORTA 0.16 13:15-17:00	Lecture 11 Various	Working College Thu 15:15-17:00
3	Tue Jan 17 in BBG-083 10:00-11:45	Lecture 12 Probability	Working College Tue 9:00-10:00
3	Thu Jan 19 in PORTA 0.16 13:15-17:00	Lecture 13 Bidirectional	Working College Thu 15:15-17:00
4	Tue Jan 24 in PORTA 0.19 10:00-11:45	Lecture 14 TAA & ReSTIR	Working College Tue 9:00-10:00
4	Thu Jan 26 in BBG-061 13:15-17:00	Lecture 15 Learning GI / exam
	Block 2 Exam Thu Feb 2, 17:00 - 19:00 in EDUC-MEGARON					Deadline: Wed Feb 1, 17:00h

Downloads

LECTURE SLIDES and RECORDINGS

Lecture 1: Introduction
Lecture 2: Whitted
Lecture 3: Light Transport
Lecture 4: Path Tracing
Lecture 5: Acceleration Structures
Lecture 6: The Perfect BVH
Lecture 7: GPGPU Ray Tracing (1)
Lecture 8: Variance Reduction (1)
Lecture 9: Variance Reduction (2)
Lecture 10: GPGPU Ray Tracing (2) (updated TL;DR version)
Lecture 11: "Various"
Lecture 12: Probability Theory
Lecture 13: Bidirectional
Lecture 14: TAA, ReSTIR et al.
Lecture 15: Learning GI, Exam Prep

Please find ecordings for the course in Teams.

SUPPLEMENTAL MATERIAL

Will be made available in Teams.

FILES

C/C++ coding template: on Github.

More content may be made available during the course.

RENDERERS

Lighthouse 2 can be found on GitHub.
VoxelWorld template is also available on GitHub.

Practical Assignments

The course includes a software project that should be worked on in pairs. It is allowed to work on this alone, but be aware that the scope of the project is tuned for duos.

There are three milestones for this project:

Basics: during the first phase of the project, you will design and implement a Whitted-style ray tracer, either built on your own framework, or as a render core for the Lighthouse 2 renderer.
Interactivity: based on the theory, you will transform the Whitted-style ray tracer into an interactive renderer. The renderer is extended with basic animation support.
For the final version of your project, you will be adding global illumination to the renderer. The default approach for this is a path tracer; however other options exist as well. You are free to chose your specific focus in this phase of the project, e.g. GPU rendering or advanced variance reduction.

The final grade for the software project is calculated as follows:

practical grade = (P1 + P2 + 2 * P3) / 4

(1) Ray Tracer

Tasks:

Setup a basic ray tracing framework for rendering a depth map for a hard-coded scene consisting of spheres and planes
Implement a complete Whitted-style ray tracer with reflection and optionally refraction (Fresnel) and absorption (Beer)

Click here to download the formal assignment description.

(2) Interactive Ray Tracer

Tasks:

Add a bounding volume hierarchy
Optional: add a top-level BVH
Optional: add ray packet traversal
Other optional challenges available.

Click here to obtain the formal assignment description, IN CONCEPT - may change slightly.

(3) FreeStyle

Tasks (tentative):

Implement recent research in the field of graphics
Build a GPU ray tracer or path tracer.
Other challenges are available.

Click here to obtain the formal assignment description (v2).

Grading

GRADING

In order to pass the course, you must meet these requirements:

Practical grade P = (P1 + P2 + 2 * P3) / 4
Exam grade E
Final grade F = (2 * P + E) / 3

Where

P >= 4.5
E >= 4.5
F >= 5.5.

RETAKES AND REQUIREMENTS

There will be an opportunity for a retake exam or a retake assignment. In order to qualify, a grade of at least 4.0 is required in both areas (final exam, practicals). The retake exam or assignment replaces the matching exam or assignment.

IMPORTANT: you can only take the retake exam if you have both a high-enough but non-passing grade (i.e., at least 4.0 and less than 5.5).

Transfers from the previous lecture

If you are retaking this course it may be possible to transfer partial grades to this academic year. This is only possible for practical assignment grades; if you are retaking Advanced Graphics, you must retake the exam. Contact me for details.

Literature & Links

LITERATURE

T. Whitted. An Improved Illumination Model for Shaded Display. Commun. ACM, 23(6):343–349, 1980.
Interactive Rendering with Coherent Ray Tracing, Wald et al., 2001.
Large Ray Packets for Real-time Whitted Ray Tracing, Overbeck et al., 2008.
Fast Agglomerative Clustering for Rendering, Walter et al., 2008.
Heuristics for Ray Tracing using Space Subdivision, MacDonald & Booth, 1990.
Distributed Ray Tracing, Cook et al., 1984.
The Rendering Equation, Kajiya, 1986.
Importance Sampling for Production Rendering, pages 5-38.
Ray tracing on programmable graphics hardware. Purcell et al., 2002.
Interactive k-d tree GPU raytracing. Horn et al., 2007.
Understanding the Efficiency of Ray Tracing on GPUs. Aila & Laine, 2009.
Getting Rid of Packets - Efficient SIMD Single-Ray Traversal using Multi-branching BVHs. Wald et al., 2008.
Megakernels Considered Harmfull: Wavefront Path Tracing on GPUs. Laine et al., 2013.
Theory for Off-Specular Reflection from Roughened Surfaces. Torrance & Sparrow, 1967.

Recommended literature

Physically Based Rendering - From Theory to Implementation, Third Edition, Pharr & Humphreys. Morgan Kaufmann, 2016. ISBN-10: 9780128006450. Also available for free online: www.pbrt-book.org.

PAPERS & ONLINE MATERIALS

Additional materials will be posted here in due time.

News Archive

Old posts

Jan 10:

Assignment 3 has been updated: deadline (Feb 3) and some details have changed.
New slides for lecture 10 are now available.

Jan 9:

Schedule has been adjusted because of the events before Christmas.

Dec 19:

Click here to download the slides for lecture 10.

Dec 12:

Slides for lecture 8 are now available.

Dec 7:

Slides for lecture 7 have been added.

Dec 5:

Important: Tomorrow's lecture starts at 9.15!
Slides for lecture 6 have been added.
Assignment 2, in concept, has been added. This may change slightly if needed.

Nov 29:

Slides for lecture 5 have been added.

Nov 28:

Slides for lecture 4 have been added.

Nov 23:

Changed order of lectures to better match assignment deadline, see schedule.
Slides for lecture 3 have been added.

Nov 21:

Rooms for almost all lectures have changed, see schedule.
Slides for lecture 2 (in concept) are now available for download.

Nov 17:

Block schedule updated: Tuesday lectures start at 10am!
Assignment 1 is available for download.
Slides for lecture 1 now available.

Nov 15:

C/C++ coding template for 2022/2023 now available.

Nov 7:

Please join us on Teams!
Initial version of the website.