Virtual Reality and Physically-Based Simulation WS 16/17


Virtual Reality (VR) is a research area at the intersection of computer graphics, physically-based simulation, and 3D human-computer interaction (HCI). VR and 3D realtime computer games share a lot of algorithmic challenges: novel interaction technologies and interaction metaphors in virtual environments (in particular intuitive and direct metaphors), immersion and presence, and real-time rendering. Another important topic is physically-based simulation in real-time, which tries to simulate real-world phenomena such as fire, cloth, the behavior of rigid objects when colliding with each other, fluids, or objects made of deformable material.

Over the past one or two decades, VR has established itself as an important tool in several industries, such as manufacturing (e.g., automotive, airspace, ship building), architecture, and pharmaceutical industries. In the past few years, we are witnessing the second "wave" of VR, this time in the consumer, i.e., entertainment markets. (Some people might argue that it is actually the third wave.)

In this course, we will first look at the fundamental methods, and then go on to more advanced algorithms that are needed to build complex and full-fledged VR systems or real-time computer games. Example topics are object behavior, acoustic rendering, haptics, and collision detection.

The assignments will be mostly practical ones, based on the cross-platform VR system InstantReality. Participants can choose the programming language from Java, Javascript, and C++.
You are encouraged to work on assignments in small teams.

Some of the topics to be covered (tentatively):

  1. Introduction, basic notions of VR, a few applications
  2. VR technologies: displays, tracking, input devices, software design
  3. Stereo rendering
  4. Error correction: tracking correction, filtering
  5. Techniques for real-time rendering
  6. Fundamental immersive interaction techniques: gesture recognition, navigation, selection, grasping, menues in 3D
  7. Complex immersive interaction techniques: world-in-miniature, action-at-a-distance, magic lens, etc.
  8. Particle systems
  9. Spring-mass systems
  10. Force feedback: rendering forces
  11. Collision detection
  12. Acoustic rendering

Note: this list is just tentative and subject to change during the semester.

News


Slides

The following table will, eventually, contain all the topics that were covered in this class, the accompanying slides, exercise sheets, and frameworks for solving the programming exeercises. (This table will be filled week by week.)

Week Topics Slides Exercise
sheets 		Frameworks
1. Orga stuff
Introduction: definitions, immersion, fidelity, presence, history, Milgram's continuum
PDF0 PDF1
2. Scenegraphs: immediate / retained mode, semantics of nodes and edges, special issues with light sources, shared geometry (instancing), thread-safe scenegraphs, distributed rendering, fields & routes concept, types of nodes, specification of the material using the Phong model, indexed face set, hierarchical transformations, routes & events, behavior graph, KV pool. PDF Assignment 1
3. Displays and Stereo rendering 1: depth cues, human visual system and stereopsis, horopter and fusion area, multiplexing stereo images, multiplexing techniques for stereo images (polarization, shuttering, color filtering), immersive projection technologies PDF Assignment 2
4. Dies Academicus
5. Stereo rendering 2: correct stereo projection, issues with stereo rendering (depth aliasing, convergence-focus incongruity, in-correct viewpoint, stereo violation), hypo- and hyper-stereo, model of user's head, projetion issues for multiple co-located users, multiplexing for multiple users, automultiscopic display, pre-distortion for HMDs, low and full persistence, space-time diagrams, smearing and judder and color fringes. PDF
6. Real-time rendering 1: simulator sickness, latency and its sources, view-independent rendering, prioritized rendering, level-of-detail techniques, static/dynamic/psychophysiological LOD selection, predictive LOD selection PDF Assignment 3
Evaluation presence 		Jump & lag
VR Horopter
7. Real-time rendering 2: dynamic LODs, progressive meshes, view-dependent LODs, portal culling, state sorting using online sorting buffer algorithms, stereoscopic image warping,
PDF
8. Input Devices: degrees of freedom, multimodality, virtual trackball, directness continuum, isotonic vs isometric, tracking, data gloves, locomotion devices
 PDF Assignment 4
9. Interaction techniques 1: Universal Interaction Tasks, design of user interfaces, gesture recognition, the navigation task (wayfinding & locomotion), taxonomies as a design tool, abstract representation of the user for navigation, navigation metaphors (point-and-fly, scene-in-hand, two-handed, walking in place, et al.), user models (power law of practice, Hick's law, Fitts's law), PDF
10. Interaction techniques 2: iso-/non-isomorphic techniques, control-display ratio, go-go technique, task decomposition of selection task, selection techniques: ray-based & cone-based techniques, friction surface (bent ray), eye-hand mismatch, cone-based technique with ranking, balloon selection, object manipulation (grasping and moving), DOF separation/reduction by widgets, principles for interaction design: action-at-a-distance, image plane interaction, proprioceptive interaction, world-in-miniature, voodoo dolls, magic lenses, redirected walking and related techniques, PDF Assignment 5
Evaluation lag
Lag 2015
11. Particle systems: dynamics/kinematics, Euler integration, phase space, definition of particle systems, physical effects, non-physical effects, collision handling, rendering, rendering transparent objects, flames & fire, procedural modeling of plants, PDF
12. Mass-spring systems: Newton's Laws, single spring-damper element, explicit Euler integration, instability and error accumulation with explicit Euler integration, Runge-Kutta, implicit integration, tangent stiffness matrix, comparison to explicit integration, mesh creation for volumetric objects, PDF Assignment 6 Mass-spring framework
13. Haptics: applications, devices, the haptic loop, human haptic sense and factors, simulation factors, haptic textures, buzzing, intermediate representations, impedance and admittance, surface contact point approach, voxmap-pointshell method, friction in one contact point, PDF
14. Collision detection: motivation, definitions, collision detection pipeline, broad/narrow phase, plane-sweep technique, Mikowski sums, intersection test for convex objects based on Minkowski sums, hierarchical coll.det., bounding volume hierarchies, types of BV's, separating axis lemma for convex polyhedra, overlap test for k-DOP's, construction of BVH's, inner sphere trees, sphere packings, proximity computation using ISTs, penalty forces using ISTs.
 PDF

Literature

Warning: these text books can only give you a general introduction to the field of VR! Most of the topics taught in class will not be covered by any of these text books directly -- in fact, AFAIK there are no text books that cover these topics. Therefore, I recommend to attend class.

If you are thinking of buying some of these books, then I suggest to consider buying a used copy of them -- very often, you can find them at a fraction of the price of a new copy. The following are two very good internet sites for finding inexpensive used copies of books: Abebooks and BookButler.

Assignments

In order to acquire the "Schein", you will have to do a number of assignments. These will be mostly small practical programming assignments (based on a freely available VR system).

Online Literature and Resources on the Internet

Literature and Resources on X3D/VRML
Since X3D/VRML is no longer the platform for the practical exercises in this course, I have demoted the links to X3D/VRML to this place.

Readings That Have Nothing to do With VR, but are Still Highly Recomended

Gabriel Zachmann
Last modified: Wed Feb 01 23:01:41 CET 2017