"The ShapeJS language provides a powerful system for generating 3D printable objects via a simple Javascript program. ShapeJSs work on a voxel representation. A voxel is similar to a 2D pixel but it represents a volume element in 3 dimensional space. A script provides mechanisms to easily set the desired voxels using a series of data sources and transformations."

Read more at http://shapejs.shapeways.com/