Camera Control in Computer Graphics

1. Camera Control in Computer Graphics • Marc Christie (Université de Nantes, France) • Patrick Olivier (Newcastle University, UK)

2. Introduction • hard to over emphasize the importance of effective camera control (positioning & movement) • central issue in a number of applications both current (e.g. visualization & games) and future (visual analytics & interactive story telling) • relatively under-researched: • open issues in formulating requirements & evaluation criteria • intrinsic complexity of basic geometric characterization • clearly it is possible to create customized procedural controllers for cameras... SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

3. Tutorial goals • review existing camera control schemes • motivate through empirical evidence: • application requirements • current practice (film and new media) • general camera control formulations • representation & reasoning requirements • characterize camera control research agenda SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

4. Tutorial: structure • applications & motivations for camera control • camera control and cinematography • interactive control • automated approached • dealing with occlusion • closing remarks and open issues SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

5. Smart graphics agenda “synthesis of graphics utilizing an explicit model of the user, application & computational context” • user: cognitive (perception, motor, memory & reasoning)... • application: physical, functional, teleological, ... • computational: processing, display, interaction devices, ... • typically utilizes explicit models of one or more • plenty of examples beyond camera control: • perceptual graphics, intelligent user interfaces • requires representation & reasoning about graphics SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

6. Motivations: applications • exploring motivations and characteristics • review application practice • review cinematographic practice • relevant application domains: • modelers • games • visualization • multimodal systems • camera control problem depends upon: • application domain • nature of the user • balance of interactive and automated control SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

7. Application: 3D modelers SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

8. Application: 3D modelers SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

9. Application: 3D modelers • 3D artists specify: • camera position • look-at / up vectors • control provided: • classical interpolation methods (splines with key frames/control points) • fine control of the velocity curves supported • target constraints supported • other basic notions from cinematic practice are not supported (e.g. framing) • designer is the cameraman (not the director) SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

10. Multimodal systems • generation of coordinated natural language and graphics • typically the problem is generating a camera set-up (for an existing model) to support the linguistic references • existing (but unsatisfactory) solutions: • predefined views (using “canned” references) • cutaways and transparency (overcome occlusion) • multiple viewports (overcome occlusion) • full requirements (“co-generation” of language & graphics): • linguistically felicitous graphical synthesis • sensitivity to viewer’s scene cognition • sensitivity to semantics of spatial language SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

11. Multimodal systems • default views • transparency • Seligmann & Feiner [SF91,SF93] • multiple views • Bares & Lester [BL99] SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

12. Visualization • conceptually more straight forward • configurations: • essentially spatial data (sci viz) • spatial metaphors for multidimensional data (data viz) • spectrum of camera control support: • full interactive control • constrained interaction • fully autonomous • nature of constraints arises from: • the application (and task being supported) • underlying knowledge base SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

13. Visualization SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

14. require camera control during game play (real-time) between game play (cut scenes) available resources tightly constrained classes of viewpoint first person third person bird’s eye cinematic key problems: occlusion vs geometric complexity gameplay vs cinematic qualities visual consistency Application: Games SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

15. “Problems such as clunky controls and a frustrating camera, which were excusable in the early games, have steadily degraded the quality of the series releases over time.... Once you get the hang of it you can effortlessly overcome even the most imposing obstacles without difficulty. It's also always abundantly clear which ledges you can hang on or jump between, so the only challenge is positioning the camera so you can see where you're trying to go, which can be frustrating. In tight spots it can be difficult to get a good view of the ledge you need to jump to, and sometimes it's easy to misjudge a jump if you don't have the camera aligned just right. The camera problems are intermittent though, and most of the time you have a fairly good view of the surroundings.” http://shopper.cnet.com/Tomb_Raider_Legend_PC/4512-9696_9-31568589.html Application: Games SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics

16. Games and the movies... SIGRAPH ASIA 2009 Tutorial: Camera Control in Computer Graphics