Non-Photorealistic Rendering Mario Costa Sousa Department of Computer Science University of Calgary Mario Costa Sousa Department of Computer Science University of Calgary

Computers: Process, Transform, Communicate Origin (where does information come from?) Throughput (how frequent?) Latency (how long do I have to wait)? Presentation (what does it look like?) Information Computers Graphics: technology for presenting information

What impresses most people is the photorealistic quality of the images Computer Graphics:

Information transported by an image can take many different forms

Photograph of a sailboat Vast amount of information: Time of day The weather Wind direction Speed Relationships between boat and environment etc…

HOWEVER… Little use to someone attempting to build a sailboat! A sailboat builder would certainly prefer: Technical drawings, blueprints Line drawing representations of boat parts Sketches of design ideas

Imagery generated by illustrators (artistic, technical, scientific) has been used to provide information that may not be readily apparent in photographs or real life. Traditionally…

Imagery generated by illustrators (artistic, technical, scientific) has been used to provide information that may not be readily apparent in photographs or real life. Non-Photorealistic Rendering (NPR): Apply a similar goal to computer generated-images Apply a similar goal to computer generated-images New field of research in computer graphics New field of research in computer graphics Traditionally…

Photorealism Driving force behind computer graphics for the past 35 years Driving force behind computer graphics for the past 35 years Quality of image judged by how closely they resemble a photograph Quality of image judged by how closely they resemble a photograph Images are rendered by running a physics-simulation which emulates the behavior of light inside the modeled scene Images are rendered by running a physics-simulation which emulates the behavior of light inside the modeled scene Driving force behind computer graphics for the past 35 years Driving force behind computer graphics for the past 35 years Quality of image judged by how closely they resemble a photograph Quality of image judged by how closely they resemble a photograph Images are rendered by running a physics-simulation which emulates the behavior of light inside the modeled scene Images are rendered by running a physics-simulation which emulates the behavior of light inside the modeled scene

Effects needed for realism Shadows Shadows Reflections (Mirrors) Reflections (Mirrors) Transparency Transparency Interreflections Detail (Textures etc.) Detail (Textures etc.) Complex Illumination Complex Illumination Realistic Materials Realistic Materials And many more And many more

Non-Photorealistic Rendering (NPR) Images are judged by how effectively they communicate. Images are judged by how effectively they communicate. Involves stylization and communication, usually driven by human perception Involves stylization and communication, usually driven by human perception Knowledge and techniques long used by artists and illustrators Knowledge and techniques long used by artists and illustrators Emphasis on specific features of a scene, expose subtle attributes, omit extraneous information Emphasis on specific features of a scene, expose subtle attributes, omit extraneous information Brings together art and science Brings together art and science Images are judged by how effectively they communicate. Images are judged by how effectively they communicate. Involves stylization and communication, usually driven by human perception Involves stylization and communication, usually driven by human perception Knowledge and techniques long used by artists and illustrators Knowledge and techniques long used by artists and illustrators Emphasis on specific features of a scene, expose subtle attributes, omit extraneous information Emphasis on specific features of a scene, expose subtle attributes, omit extraneous information Brings together art and science Brings together art and science

Non-Photorealistic Rendering (NPR) Alternate display modelsAlternate display models Increase expressive power of CGIncrease expressive power of CG Many fieldsMany fields CG revisitedCG revisited Alternate display modelsAlternate display models Increase expressive power of CGIncrease expressive power of CG Many fieldsMany fields CG revisitedCG revisited

Recipe for Image Generation Computer Science Math Linear Algebra (Matrices, Vectors) Discrete representations (Images) Physics Lighting/Energy transfer Color reflections/refraction Mechanical Engineering CAD/CAM Solid Models

Recipe for Image Generation Computer Science Math Linear Algebra (Matrices, Vectors) Discrete representations (Images) Physics Lighting/Energy transfer Color reflections/refraction Mechanical Engineering CAD/CAM Solid Models Art and Illustration Non-Photorealistic Rendering

Applications  NPR == CG&Viz! Art, Entertainment, PublishingArt, Entertainment, Publishing –Movie Production, Animation, Special Effects –Computer Games –World Wide Web –Slide, Book, Magazine, Multimedia Design Science and EngineeringScience and Engineering –Computer-Aided Design (CAD) –Simulations –Scientific Analysis and Visualization –Process Control and Monitoring Art, Entertainment, PublishingArt, Entertainment, Publishing –Movie Production, Animation, Special Effects –Computer Games –World Wide Web –Slide, Book, Magazine, Multimedia Design Science and EngineeringScience and Engineering –Computer-Aided Design (CAD) –Simulations –Scientific Analysis and Visualization –Process Control and Monitoring

Traditional Art & Illustration Art, Entertainment, PublishingArt, Entertainment, Publishing –Artists, Designers, illustrators Science and EngineeringScience and Engineering –Technical Illustrators –Scientific Illustrators or Natural Science Illustrators (medicine, botany, archeology, etc) Art, Entertainment, PublishingArt, Entertainment, Publishing –Artists, Designers, illustrators Science and EngineeringScience and Engineering –Technical Illustrators –Scientific Illustrators or Natural Science Illustrators (medicine, botany, archeology, etc)

Art, Entertainment, Publishing : Movie Production, Animation, Special Effects “What Dreams May Come” First motion picture with full NPR effects “Tarzan” “Star Wars II” “Matrix II” … Tools for artists, painting systems, pre-production

Art, Entertainment, Publishing : Computer Games, Interactive Theatre Tools for artists Painting systems Pre-production Stylized output Real-time NPR …

Art, Entertainment, Publishing : WWW, Slide, Book, Magazine, Interactive Multimedia Design Science and Engineering: Computer-Aided Design (CAD) Mechanical Engineers Land Developers Civil Engineers Landscape Architects Architects Civil Planners Scientific Analysis and Visualization Simulations MedicineBotanyArcheologyPaintings