Spline Network Extraction Tool
by Victor Gerth 2002/2004 for Peter Vize
University of Calgary, Canada
Spline Network Extraction Tool
A tool to automate the process of converting a mesh to a spline network.
The earliest functioning version of the S.N.E.T. (shown here) is a custom 3DStudio Max plugin. It operates by traversing a user designed spline based path profile. Surface positions are compared by proximity to the profile spline and radial cross sections are produced, defining the inner & outer perimeters. Finalized models must still be refined by a 3D modelor.
Dialogue Box
The interface for the Spline Network Extraction Tool. New types of crossections have been added.
The Gene Expression Viewer supports spline based model surface definitions through Spline Network Object files (files with the .SNO extension)

The SNO file format supports sequentially ordered spline segments with defined spline segmentation. Closed shapes and wrapping surfaces are handled as a special case.
Splines are defined as a sequence of knots xyz positions with in and out xyz vectors. In a closed spline the last knot is a duplicate of the first knot.
Surfaces are defined by a patch created from two spline segments of adjacent splines and ruled by the spline segments which connect the different sections.
The use of unordered spline networks and triangular patch definition solves the problem of defining branching models, however tools (such as the S.N.E.T.) still need to be developed to generate valid spline networks.