2 Lecture 31of 41 Lecture Outline Ray Tracing, Part 1 of 2: Reading for Last Class: §5.3, Eberly 2e; CGA Handout Intersections, Ray Trees & Recursion Reading for Today: Chapter 14, Eberly 2e Reading for Next Class: Ray Tracing Handout Last Time: Animation Part 3 of 3 – Inverse Kinematics William H. Hsu FK vs. IK Department of Computing and Information Sciences, KSU IK Autonomous agents vs. hand-animated movement KSOL course pages: http://bit.ly/hGvXlH / http://bit.ly/eVizrE Public mirror web site: http://www.kddresearch.org/Courses/CIS636 Analytical vs. iterative solutions Instructor home page: http://www.cis.ksu.edu/~bhsu Rag doll physics, rigid-body dynamics, physically-based models End of Material on: Particle Systems, Collisions, CGA, PBM Readings: Today: Ray Tracing, Part 1 of 2 Last class: §5.3, Eberly 2e – see http://bit.ly/ieUq45; CGA Handout Vectors: Light/shadow (L), Reflected (R), Transmitted/refracted (T) Today: Chapter 14, Eberly 2e Next class: Ray Tracing Handout Basic recursive ray tracing: ray trees Reference – Wikipedia, Ray Tracing: http://bit.ly/dV7lNm Next Class: Ray Tracing Lab Reference – ACM Ray Tracing News: http://bit.ly/fqyZNQ CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 3 4 Acknowledgements: Where We Are Inverse Kinematics, Ray Tracing David C. Brogan Visiting Assistant Professor, Computer Science Department, University of Virginia http://www.cs.virginia.edu/~dbrogan/ Susquehanna International Group (SIG) http://www.sig.com Renata Melamud Ph.D. Candidate Mechanical Engineering Department Stanford University http://micromachine.stanford.edu/~rmelamud/ Dave Shreiner & Brad Grantham Adjunct Professor & Adjunct Lecturer, Santa Clara University ARM Holdings, plc http://www.plunk.org/~shreiner/ http://www.plunk.org/~grantham/ CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 5 Review [1]: 6 Review [2]: Kinematics & Degrees of Freedom Joint Types Adapted from slides 2000 – 2005 D. Brogan, University of Virginia Adapted from slides 2002 R. Melamud, Stanford University CS 551, Advanced CG & Animation – http://bit.ly/hUXrqd Mirrored at CMU 16-311 Introduction to Robotics, http://generalrobotics.org CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 7 Forward Kinematics: 8 Review [3]: Joint Angles to Bone Coordinates Forward Kinematics ? 3 2 End Effector 1 Base θx )f( f Φe Choi Rotenberg Adapted from slides 2004 – 2005 S. Rotenberg, UCSD Adapted from slides 2002 K. J. Choi, Seoul National University CSE169: Computer Animation, Winter 2005 – http://bit.ly/f0ViAN Graphics and Media Lab ( http://graphics.snu.ac.kr ) – mirrored at: http://bit.ly/hnzSAN CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 9 Review [4]: 10 Inverse Kinematics: Inverse Kinematics Issues For more on characters & IK, see: Advanced Topics in CG Lecture 05 ? 3 2 ? End Effector 1 Base 1 xθ )(f f 1eΦ Choi Rotenberg Adapted from slides 2002 K. J. Choi, Seoul National University Adapted from slides 2004 – 2005 S. Rotenberg, UCSD Graphics and Media Lab ( http://graphics.snu.ac.kr) – mirrored at: http://bit.ly/hnzSAN CSE169: Computer Animation, Winter 2005 – http://bit.ly/f0ViAN CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 11 Review [5]: 12 Review [6]: Inverse Kinematics Demos Ragdoll Physics Type of Procedural Animation Automatically generates CGA directives (rotations) Based on simulation Rigid-body dynamics Articulated Figure Gravity © 2008 M. Kinzelman © 2007 A. Brown No autonomous movement http://youtu.be/l52yZ491kPo http://youtu.be/6JdLOLazJJ0 Falling Bodies © 1997 – 2001 Animats Used for inert body http://www.animats.com Usually: character death (car impact, falling body, etc.) Less often: unconscious, paralyzed character Collisions with Multiple Bodies Inter-character Character-object © 2008 T. Komura, H. S. Lim, & R. W. H. Lau © 2011 K. Iyer http://youtu.be/FJTBMnP6oCM http://youtu.be/YvRBWIRAPsE CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 13 Review [7]: 14 Review [8}: Ragdoll Physics Demos Physically-Based Modeling (PBM) Particle Dynamics Emitters 0-D (points), 1-D (lines), 2-D (planes, discs, cross-sections) e.g., fireworks (0-D); fountains (0/1/2-D); smokestacks, jets (2-D) Simulation: birth-death process, functions of particle age/trajectory Rigid-Body Dynamics © 2006 P. Pelt © 2007 N. Picouet http://youtu.be/6JdLOLazJJ0 Constrained systems of connected parts http://youtu.be/ohNqCb--aSs See also: http://youtu.be/5_QIsI0fyaU Examples: falling rocks, colliding vehicles, rag dolls Articulated Figures: Primarily IK Rocks fall More References Everyone dies ACM, Intro to Physically-Based Modeling : http://bit.ly/hhQvXd Wikipedia, Physics Engine: http://bit.ly/h4PIRt Wikipedia, N-Body Problem: http://bit.ly/1ayWwe PBM System: nVidia (Ageia) PhysX: http://bit.ly/cp7bnA © 2009 M. E. Cerquoni © 2010 M. Heinzen (Arkaein) http://youtu.be/uW_DK2qvKv8 http://bit.ly/gUj9Su / http://youtu.be/FJTBMnP6oCM CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 15 Ray Tracing [1]: 16 Ray Tracing [2]: Overview Why Use It? What is it? Simulate rays of light Why use it? Produces natural lighting effects Basics Advanced topics Reflection Depth of Field References Refraction Motion Blur © 2006 – 2007 H. Kuijpers, Soft Shadows Caustics Capgemini Netherlands http://bit.ly/erkKrC Hard to simulate effects with rasterization techniques (OpenGL) Rasterizers require many passes Ray-tracing easier to implement Adapted from slides 2001 D. Shreiner & B. Grantham, SCU Adapted from slides 2001 D. Shreiner & B. Grantham, SCU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 17 Ray Tracing [3]: 18 Ray Tracing [4]: Who Uses It? Brief History Entertainment (Movies, Commercials) Decartes, 1637 A.D. - analysis of rainbow Games pre-production Arthur Appel, 1968 - used for lighting 3D models Simulation Turner Whitted, 1980 - “An Improved Illumination Model for Shaded Display” really kicked everyone off. 1980-now - Lots of research Adapted from slides 2001 D. Shreiner & B. Grantham, SCU Adapted from slides 2001 D. Shreiner & B. Grantham, SCU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 19 Ray Tracing [5]: 20 Ray Tracing [6]: Basic Operations Basic Idea Simulate light rays from light source to eye Generating Rays Intersecting Rays with Scene Lighting Eye Light Shadowing Reflections ay Inc ed r iden lect t ray Ref Surface Adapted from slides 2001 D. Shreiner & B. Grantham, SCU Adapted from slides 2001 D. Shreiner & B. Grantham, SCU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas State University 21 22 “Forward” Ray Tracing “Backward” Ray Tracing Trace rays from light Trace rays from eye instead Lots of work for little return Do work where it matters Light Light Image Image Light Rays Plane Plane Eye Eye Object Object This is what most people mean by “ray tracing”. Adapted from slides 2001 D. Shreiner & B. Grantham, SCU Adapted from slides 2001 D. Shreiner & B. Grantham, SCU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU COEN 290: Computer Graphics I, Winter 2001 – http://bit.ly/hz1kfU CIS 536/636 Computing & Information Sciences CIS 536/636 Computing & Information Sciences Lecture 31 of 41 Lecture 31 of 41 Introduction to Computer Graphics Kansas State University Introduction to Computer Graphics Kansas