Non-Photorealistic Renderingor

More-Interesting Rendering(in a more positive sense)

Presented by Adam Smith

for CMPS160

What is NPR?

• NPR is showing an image that purposely differs from photographic representation.

• May or may not be true to nature on any number of levels– Simulations of artists real tools– Made-up systems simulate non-

natural processes

Why is NPR used?

• Convey more information• Eliminate distracting

information• Create art

– “artificial creativity” (human or not, does it matter?)

– Meta-creativity of algorithm designer

Categorization of Methods

• User control– Very interactive

• User pokes / paints / scrapes to build image

– Fully automatic• User feeds in input, views output

• Input Types– 3d scenes (geometry)– 2d images (raster or vector)– Direct input (brushstrokes)

Automatic Brush Stroke Rendering

• Are strokes stuck to canvas or object?– Canvas:

• Shower-door effect• More natural look• (cablecar.avi)

– Object:• A painted 3d world• More abstract• (hay.avi)

QuickTime™ and aCinepak decompressor

are needed to see this picture.

QuickTime™ and aCinepak decompressor

are needed to see this picture.

Pen and Ink SketchHigh Contrast Methods

• Print nicely (on b&w only printers)

• Harmonize with text

• Can eliminate unnecesary details

• Can still represent small important details

Stylized Halftoning

Represents different materialswhen color is not available.

Encodes importance data.

Example: Real-Time Hatching

• Hatching conveys:– Material– Tone– Form

Oh no!

• Excel doesn’t support .wmv’s!

• {hatching.wmv goes here}

Toon/Cel Shading

• Silhouete outlines

• Shadows

• Highlights

• Simple lines

Simulation of Traditional Media

• Draw with accurately simulated brushes, crayon scrapes, chalk buildups

Non-traditional Perspective

Khronos Projector

• We saw creative mapping from 3D of space to 2D of space.

• How about a creative mapping from 3D of spacetime to some other 3D of spacetime?

QuickTime™ and aMPEG-4 Video decompressor

are needed to see this picture.

Stylized Motion

• Convey motion (change over time) in a 2D image.

• Examples:– Speed lines– Motion blur– Squash and stretch

“Video Tooning”

• Generating a cartoon-looking image from a single frame of animation is easy (relatively)

• It’s hard to make a full animation look hand drawn.

• Video…

VideoTooning.WMV

• Ugh… gotta switch back to VLC again

Technical Illustration

Scientific Visualization