WYSIWYG NPR: Drawing Strokes Directly on 3D Models

Paper by: Robert D. Kalnins, Lee Markosian, Barbara J. Meier,

Michael A. Kowalski, Joseph C. Lee, Philip L. Davidson,Matthew Webb, John F. Hughes and Adam Finkelstein.

Presentation by:Nathan F. Cantelmo

Table of Contents

● WYSIWYG NPR Overview● Interface Descriptions● Rendering System & Shaders● Stroke Styles & Features● Hatching & LOD Methods● Summary & Conclusions● Points for Discussion

WYSIWYG NPR Overview

● What is WYSIWYG NPR?● How does it work?● Who should use it?● What purpose does it serve?

Interface Descriptions

● Tablet, mouse, or keyboard used for input● Three editing modes:

● Line editing mode

● Hatching editing mode

● Basecoat editing mode

Line Editing Mode

Hatching Editing Mode

Basecoat Editing Mode

Rendering System & Shaders

● Triangle mesh used for models● Mesh divided into patches● Each patch rendered by four shaders:

● Background and base coat shader

● Stroke formation shader

● Stroke visibility shader

● Media simulation shader

Rendering System & Shaders

Stroke Styles & Features

● Four types of strokes:● Decal strokes

● Crease strokes

● Silhouette strokes

● Hatching strokes

Stroke Styles & Features

Hatching & LOD Methods

● Two types of hatching: ● Fixed hatching

● Mobile hatching

● Two types of LOD control: ● Structured hatching

● Free hatching

Hatching & LOD Methods

Summary & Conclusions

● Strengths of WYSIWYG NPR● Weaknesses of the system● Continuing work:

● Jot

● Coherent Stylized Silhouettes

Points for Discussion

● How might the stroke visibility algorithm be improved?● Could individual silhouettes be annotated uniquely?● What other, unmentioned shortcomings exist?● Other questions, comments, etc.