A Processing-based application which generates parametric seashells, some found in nature, most not. The interface allows you to adjust 14 parameters which determine the spirality, orientation, and surface features of a classical mollusk shell. There are about 15 presets which model various gastropods, bivalves, and cephalopods.
To run this, you need Processing installed. Confirmed working on 1.5.1, untested but probably fine on 2.0.
Load the program and behold the beautiful Precious Wentletrap. Click-dragging the mouse rotates the shell and two finger-scroll zooms. Sliders controlling the parameters are on the left. For a full explanation of what they do, read the paper. The easiest to use one is "Turns" which controls how many revolutions the spiral makes.
View and export
"Live" mode continuously generates the mesh in real time as you change parameters, albeit at a lower resolution. "Nomral" mode is higher-resolution, but updates only when you click "update" or spacebar. "Hi-res" is the same but an even higher resolution and slower render.
You can control the color and transparency of the mesh with the color sliders, and view the shell as a wireframe.
The mesh can be exported to an 3d-printer ready STL file, with the export feature on top right. The STL file goes to the export folder. If you want to print it, you first need to run through this process in MeshLab (free) to thicken the walls of the mesh, and scale it to the right size.