(MIT News: Cambridge, MA) -- MIT researchers have devised a technique that reverse engineers complex 3D computer-aided design (CAD) models, making them far easier for users to customize for manufacturing and 3D printing applications.

Nearly all commercial products start as a CAD file, a 2D or 3D model with the product’s design specifications. One method that’s widely used to represent today’s 3D models is constructive solid geometry (CSG), a technique where numerous basic shapes, or “primitives,” with a few adjustable parameters can be assembled in various ways to form a single object. When finalized, the compiled digital object is converted to a mesh of 3D triangles that defines the object’s shape. These meshes are used as input for many applications, including 3D printing and virtual simulation.

Customizing that mesh, however, is no easy task. For example, adjusting the radius in one portion of the object requires individually tweaking the vertices and edges of each affected triangle. With complex models comprising thousands of triangles, customization becomes daunting and time consuming. Traditional techniques to convert triangle meshes back into shapes don’t scale well to complex models or work accurately on low-resolution, noisy files.

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