To be able to work with non-canonical origami designs, we implemented software that would allow free-form manipulation of helices directly in 3D space. The software was implemented as a plug-in for Autodesk Maya (several versions) and is available at http://www.vhelix.net. The associated source code can be found at https://github.com/gardell/vHelix. a, The interface in vHelix when viewing the design of the ball structure. b The ‘Helix’ menu provides most of the functionality, such as the ability to create new helices, disconnect and connect bases. c, Close-up of a connected vertex. Selecting a base shows its associated connectivity by highlighting all connected bases and displaying the associated sequence if a sequence has been applied. d, Using the “apply sequence” command to one of the strands (the scaffold), the plug-in calculates the sequence of all paired bases (on the staple strands) and subsequently the command “export strands” generates a spreadsheet file containing the staple-strand sequences. The physical dimensions of the DNA model follows what is usually used in DNA nanotechnology design processes (that is, a 2-nm helical radius, a 0.334-nm rise, a 34.286° pitch and a 155° minor groove). e, Overlaying the model with crystallography data from the literature39 shows that the model fits natural DNA well.