Animated Embroidery:
A Teapot in Modern Blackwork

An exploration of new domains of computer graphics through uncommon media, pushing the bounds of non-photorealistic rendering (NPR). This work uses NPR methods to move beyond the common pen-and-ink or impressionist oil painting styles.

It implements computer-generated blackwork, a decorative art of embroidery that originated in Elizabethan times, to add detail to clothing. The basic techniques of blackwork were later used as an illustrative form, and the technique was revived in the mid-20th century. This work adapts the approach to computer graphics and shows how iconic objects such as the Utah teapot (and the less-well-known teacup) can be rendered anew using vintage media. It adds a very uncommon twist: animating embroidery, a medium that does not lend itself to moving images.

This modern interpretation renders polygonal objects using computer graphics techniques and uses computer-controlled embroidery machines to translate them to embroidered panels. Using the venerable Utah teapot as the subject for a still life connects a tradition in the field of computer graphics to a centuries-old art form.

Technical Overview
Blackwork is characterized by the use of straight stitches on a contrasting color fabric, most commonly black thread on white linen. Traditional blackwork can be seen in Elizabethan period paintings in the form of edgings along cuffs and collars, as well as broader areas embellished with figures filled with intricate patterns. More modern interpretations of blackwork, beginning around 1950, use repeating fill patterns to create representational images from the contrasting lights and darks. The effect of this more modern blackwork resembles that of a pen-and-ink drawing using very elaborate hatching patterns, where the sum of strokes in a region produces a target tone.

Translated into modern computer graphics, 3D polygonal shapes are rendered, not as pixels to be transferred to colored stitches, but as individual strokes of dark thread on a light cloth field. The process is not image-based. It generates the directives from a graphics pipeline employing common tools for shading and illumination and hidden surface removal. Ultimately, however, scan conversion is transformed into stitch placement, and the result is a control file for an automated embroidery machine.

The Utah teapot is used here as a subject for a "not-so-still life," connecting a traditional icon of computer graphics to an ages-old decorative craft formerly used to embellish the garments of royalty. In a new spin on this medium, the representation is animated using a rudimentary scene graph that creates a short loop sequence of 12 panels mounted on a zoetrope, a primitive viewer for moving images, which animates blackwork for perhaps the first time.

Penny Rheingans
David T. Chen
Marc Olano
Bradley Lowekamp
Terry S. Yoo

Contact
Terry S. Yoo
OHPCC/NLM/NIH
Yoo (at) nlm.nih.gov