Sketching garments for virtual characters Sketch-Based Interfaces and Modeling 2004 Sketching garments for virtual characters Emmanuel Turquin GRAVIR Marie-Paule Cani GRAVIR John F. Hughes Brown University Grenoble, France Grenoble, France Providence, USA

Outline Introduction Contributions Results Conclusion

Motivations Omnipresence of virtual characters © 2003 EIDOS © 2004 PDI/Dreamworks Video games Feature films Cloth modeling still a difficult and tedious task

Related work and inspiration Cloth modeling

Cloth modeling Existing systems: Takes hours… 2D 3D [Hinds and McCartney 90, Werner et al. 93] (+ plugins for 3D suites) 3D 2D 3D [Cugini et al. 99, Bonte et al. 02]

Related work and inspiration Cloth modeling Fashion Design

Fashion design The designer’s way: Our work

Related work and inspiration Cloth modeling Fashion Design Sketch-based interfaces

Sketch-based interfaces for 3D modeling Drawing: an intuitive way of expression Existing systems Restricted to volumetric objects: Teddy [Igarashi et al. 99] Multi-views sketches: [Bourguignon et al. 01] Sketching + cloth modeling ? Positioning flat patterns: [Igarashi & Hughes 03] No 3D sketch-based technique creating open surfaces

Related work and inspiration Cloth modeling Our Work Fashion Design Sketch-based interfaces

Sketching interface for garment design Takes few minutes… Sketching interface for garment design

Problems to address Intuitive creation process Identifying elements of the drawing Inferring the third dimension

Outline Introduction Contributions Results Conclusion

Contributions Intuitive creation process Identifying elements of the drawing Inferring the third dimension

Intuitive creation process: what kind of drawing ? Shaded drawing: + A lot of information - For a computer, difficult to interpret -- For a human, difficult to draw Line drawing: - Less information + Easier to interpret ++ Easier to draw

Intuitive creation process: what kind of drawing ? Views: front (and back), like fashion design Posture: Try to avoid overlapping Rather use a « T » stance

Intuitive creation process No cloth templates: be generic Avoid distracting movements No change of tools: only paper and a pen Iterative creation process: constant visual feedback

Presentation of our method 2D Treatment Pretreatment 3D Treatment

Presentation of our method Pretreatment Body mask Load 3D model

Presentation of our method 2D Treatment Pretreatment Load 3D model

Presentation of our method 2D Treatment Body mask

Contributions Intuitive creation process Identifying elements of the drawing Inferring the third dimension

Identifying elements of the drawing Kinds of lines: Contours / Silhouettes / Borders / Folds / Seaming lines / Others… For now on: only silhouettes and borders

Presentation of our method 2D Treatment Body mask Closed curve, with the types of strokes

Contributions Intuitive creation process Identifying elements of the drawing Inferring the third dimension

Inferring the third dimension Under-constrained problem We have to choose a (default) solution Examples: or

Inferring the third dimension Under-constrained problem We have to choose a (default) solution Examples: or

Inferring the third dimension Under-constrained problem Choose a (default) solution Propagate the distance information from the contour to the body, all over the garment Speed-up distance queries by using a distance field

Presentation of our method Pretreatment Body mask Load 3D model Distance field

Presentation of our method 2D Treatment Pretreatment Load 3D model 3D Treatment

Presentation of our method 3D Treatment 1/ Strokes: For all P: distance to the body: P.dist depth value: P.z Closed curve, with the types of strokes Distance field

Presentation of our method 3D Treatment 1/ Strokes: OK 2/ Surface: Create buffer Determine the inside/outside Propagate the distance values inside the buffer For each (x,y) of the inside region, find depth Mimick cloth tension Closed curve, with the types of strokes Distance field

Mimicking cloth tension Before : After :

Presentation of our method 3D Treatment 1/ Strokes: OK 2/ Surface: Create buffer Determine the inside/outside Propagate the distance values inside the buffer For each (x,y) of the inside region, find depth Mimick cloth tension Smooth the garment Tesselate the garment Closed curve, with the types of strokes Distance field

Presentation of our method 3D Treatment 1/ Strokes: OK 2/ Surface: OK Closed curve, with the types of strokes Resulting surface Distance field

Presentation of our method 2D Treatment Pretreatment Load 3D model 3D Treatment Result

Outline Introduction Contributions Results Conclusion

Results

Results

Results

Results

Results

Results

Outline Introduction Contributions Results Conclusion

Discussion First method for dressing virtual characters from 2D sketches of their garments Fast and easy But: Only the front part Garments do not look extremely realistic

Future Work Generate a full garment, from front and back views Add expressivity: let user alter default behavior of the system Manage folds and seaming lines Take physics into account (gravity, materials, …) Flatten the 3D surface into patterns User study

Thanks for your attention. Any questions?