Example direction fields. Renderings courtesy of Mehta et al.

Wavefront OBJ, 7.5MB

C++—  optimized commandline version. 
MATLAB—  pedagogical implementation in MATLAB/GNU Octave. For simplicity, this version of the code works only on topological spheres. 
Comb—  requires Mac OS X v10.6 or greater. Comb is a generalpurpose direction field design application for Mac OS X, based on the algorithm for computing trivial connections described in our paper. Its main function is to rapidly generate smooth direction fields that satisfy some set of userspecified constraints—in particular, the user can place a set of singularities that influence field behavior. Direction fields of this type can be used for a wide variety of applications, including hair modeling, anisotropic shading, texture synthesis, and remeshing. The program takes a mesh file as input, allows a user to interactively design a direction field, and exports this field to a floatingpoint texture map or one of several common mesh formats. (Comb also includes rudimentary visualization tools which may be suitable for simple visualization applications.) Direction fields exported from Comb can easily be used in popular 3D modeling/rendering packages—for instance, images below show how direction fields can be used to control fur direction in Luxology's modo. 