Teddy is a 3d sketching tool developed by Takeo Igarashi in 1999.
It was designed as an interface for 3d graphics, allowing the creation of objects with the same ease as drawing with pen and paper.
Teddy has been supplemented by Chameleon, a tool for painting the surfaces created with Teddy.
SmoothTeddy is the official successor to Teddy, including painting function of Chameleon
Plushie was developed by Yuki Igarashi (formerly known as Yuki Mori) to automatically create sewing patterns of 3d sketches.
Knitty, also developed by Yuki Igarashi automatically creates circular knitting charts. The software determines where increases and decreases are needed to match the spacial curvature of the object.
Wrappy by Yuki Igarashi lets you create hulls around scanned 3D objects, allowing you to interactively create sewing patterns for bags etc.
The tools provided by Yuki Igarashi rely on algorithms that transform 3d-shapes into sewing or knitting patterns. While Teddy and its successors are tools for shape creation each tool has a sister project dedicated to shape conversion.
Pillow can convert arbitrary 3d-shapes into sewing patterns. It requires some human interaction to place the seams.
In the paper “Knitting a 3D Model” the Igarashis describe a technique to convert 3d shapes to knitting patterns, which is quite similar to the one used by Hinke Osinga when turning the surface of the Lorenz Manifold into crochet instructions back in 2002.
Note that the circular knitting diagrams created by these algorithms are quite common in japanese Amigurumi and can be used for knitting and crochet alike.
The algorithm used by Wrappy for creating covers of 3D objects, is described in the Paper titled “Cover Geometry Design using Multiple Convex Hulls”.