Retopology

3D mesh visible on a model of a BMW 2002

Retopology (or retopo) is a step in the 3D modeling process where an object's polygonal mesh is modified or recreated to obtain a cleaner layout while maintaining nearly the same physical shape of the model. Owing to its complexity, retopology is currently a mostly manual process but tools exist to assist 3D artists with the workflow. Automated and semi-automated retopology algorithms are an active field of research; state-of-the-art techniques provide good results in some, but not all, cases. Most organically-shaped models, especially those that are animated or used in real-time applications, must be created with clean topology to deform properly (if skeletal animation is employed), render with smooth and accurate shading, and avoid excessive polygon counts that can reduce performance.

Retopology plays an important role in numerous industries such as animation, gaming, visual effects, virtual reality, and 3D printing. In animation and gaming, retopology ensures that characters and assets deform smoothly during movement, allowing for realistic and believable animations. In visual effects, it enables the creation of high-quality models with optimal geometry for seamless integration into live-action footage, while in 3D printing it is used to optimize models for efficient printing processes.