Creating animations or game environments requires the construction of meticulously detailed 3D geometric models, an often tedious and expensive process. The aim of the work described in this paper is to partially automate this process.

The user provides an example polyhedral model E: a building, an oil rig, a spaceship, and a rollercoaster are examples from the paper. The user then specifies a collection of geometric constraints to control the shape of the synthesized model M: dimensional constraints (fixed rollercoaster track width), algebraic constraints (building aspect ratio), connectivity constraints (road networks), or large-scale constraints (the layout of town buildings).

The constraints are represented by a collection of linear equations and halfspace Boolean expressions. The algorithm then generates an evenly spaced grid of planes, assigns Boolean expressions to each lattice point, and propagates the constraints throughout the lattice. The result is a model M whose every vertex neighborhood structurally mirrors those in E, but with M satisfying the specified geometric constraints.

Although the system is limited to polyhedral models E (or to bounding boxes of curved models), and is cubic in the number of distinct face normals in E, the reported results are impressive in the complexity of the constraints handled, the quality of the synthesized models, and the speed with which they were generated. The only aspect left unclear is the difficulty for the user to detail the shape-control constraints.