The joints that belong to the same region of the closest joint
are the joints that need to be updated. The new position of eachj
i
of the closest joint’s region will update the meshAmwith the
same coordinate of the correspondingepi of the curveN(j
i¼epi
).
Thus, drawing strokes on the 3D mesh always implies a tangent
deformation on the surface, i.e. the deformation is automatically
constrained by the surface. The main advantage of sketching
directly on the 3D mesh is that it is view-independent, because
it allows the user to draw strokes from any viewpoint direction.