Gaps

We present a new approach for simplifying polygonal objects. Our method is general in that it works on models that contain both non-manifold geometry and surface attributes. It is automatic since it requires no user input to execute and returns approximate error bounds used to calculate switching distances between levels of detail, or LODs. Our algorithm, called General and Automatic Polygonal Simplification, or GAPS for short, uses an adaptive distance threshold and surface area preservation along with a quadric error metric to join unconnected regions of an object. Its name comes from this ability to "fill in the gaps" of an object. Our algorithm uses a new object space error metric that combines approximations of geometric and surface attribute error. GAPS efficiently produces high quality and drastic simplifications of a wide variety of objects, including complicated pipe structures. This ability to perform drastic simplification allows us to create levels of detail to accelerate the rendering of large polygonal environments, consisting of hundreds of objects. When viewing these models with LODs created by GAPS, we achieve a 3.5 to 5 times average speedup with little loss in image quality.