http://3d-kstudio.com/product/spline-flow/

Spline Flow is a powerful plugin for 3ds Max that allows users to create intricate, parametric objects with streamlined ease and efficiency. Its primary feature is the generation of splines that smoothly flow from one to the other and follow a specific path. That in turn allows the formation of complex objects.

Spline Flow – Parametric Spline Modeling
Spline Flow, a plugin for 3ds Max, simplifies the creation of complex parametric objects based on the splines that smoothly flow from one to the other.
Users can effortlessly generate interconnected splines following a defined path, controlling their distribution and curvature.
Beyond static design, the plugin allows animate parameters, adding dynamic elements to your creations.
Its modular approach offers flexibility, enabling visualization of final 3D models and their modifications with ease.
Spline Flow simplifies the design process, making it a valuable asset for architects, product designers, and 3D modelers.