CCCP (Coiled-coil Crick Parameterization)
A suite of tools for fitting Crick parameters1,2 for coiled-coil structures and generating structures based on parameters. Contact gevorg.grigoryan at gmail dot com with bug reports and requests.

1 F. H. Crick, "The Fourier Transform of a Coiled Coil", Acta Cryst., 6: 685 (1953)
2 G. Grigoryan, W. F. DeGrado, "Probing Designability via a Generalized Model of Helical Bundle Geometry", J. Mol. Biol., 405(4): 1079-1100 (2011)