  We present a sketch-based modeling system suitable for detail editing, based
on a multilevel representation for surfaces. The main advantage of this
representation allowing for the control of local (details) and global changes
of the model. We used an adaptive mesh (4-8 mesh) and developed a label theory
to construct a manifold structure, which is responsible for controlling local
editing of the model. The overall shape and global modifications are defined by
a variational implicit surface (Hermite RBF). Our system assembles the manifold
structures to allow the user to add details without changing the overall shape,
as well as edit the overall shape while repositioning details coherently.
