We present the first sketch-based modeling method for developable
surfaces with pre-designed folds, such as garments or leather
products. The main challenge we address for building folded surfaces
from sketches is that silhouette strokes on the sketch correspond to
discontinuous sets of non-planar curves on the 3D model. We introduce a
new zippering algorithm for progressively identifying silhouette edges
on the model and tying them to silhouette strokes. Our solution ensures
that the strokes are fully covered and optimally sampled by the
model. This new method, interleaved with devel-opability optimization
steps, is implemented in a multi-view sketching system where the user
can sketch the contours of internal folds in addition to the usual
silhouettes, borders and seam-lines. All strokes are interpreted as
hard constraints, while developability is only optimized. The
developability error map we provide then enables users to add local
seams or darts where needed and progressively improve their
design. This makes our method robust even to coarse input, for which no
fully developable solution exists.
Keywords : developable surfaces, sketch-based modeling, folds generation,
non-planar silhouettes, shape modeling