This paper introduces a framework for real-time selective refinement of arbitrary progressive meshes based on view-dependent criteria. The framework allows for efficient refinement and coarsening of meshes according to changing view parameters, using criteria such as the view frustum, surface orientation, and screen-space geometric error. The algorithm exploits view coherence, supports frame rate regulation, and is found to require less than 15% of total frame time on a graphics workstation. It also supports smooth visual transitions (geomorphs) between any two selectively refined meshes. The framework is applicable to a wide range of scenarios, including height fields, parametric surfaces, and general meshes. It is particularly effective for these cases due to the absence of a rigid subdivision structure, allowing more accurate approximations than existing schemes. The paper also presents an efficient algorithm for incremental refinement and coarsening of meshes, which is based on the PM representation and allows for real-time adaptive tessellation of surfaces. The algorithm is implemented using a set of data structures that support efficient traversal and modification of the mesh. The refinement criteria are based on three main factors: the view frustum, surface orientation, and screen-space geometric error. The algorithm is designed to be fast, with a small overhead, and is demonstrated to work well in practice. The paper also discusses the rendering of selectively refined meshes, including the generation of triangle strips for efficient rendering. It also presents results for various applications, including terrains, parametric surfaces, and general meshes. The framework is shown to be effective in reducing the computational load and improving the performance of real-time rendering of complex geometric models.This paper introduces a framework for real-time selective refinement of arbitrary progressive meshes based on view-dependent criteria. The framework allows for efficient refinement and coarsening of meshes according to changing view parameters, using criteria such as the view frustum, surface orientation, and screen-space geometric error. The algorithm exploits view coherence, supports frame rate regulation, and is found to require less than 15% of total frame time on a graphics workstation. It also supports smooth visual transitions (geomorphs) between any two selectively refined meshes. The framework is applicable to a wide range of scenarios, including height fields, parametric surfaces, and general meshes. It is particularly effective for these cases due to the absence of a rigid subdivision structure, allowing more accurate approximations than existing schemes. The paper also presents an efficient algorithm for incremental refinement and coarsening of meshes, which is based on the PM representation and allows for real-time adaptive tessellation of surfaces. The algorithm is implemented using a set of data structures that support efficient traversal and modification of the mesh. The refinement criteria are based on three main factors: the view frustum, surface orientation, and screen-space geometric error. The algorithm is designed to be fast, with a small overhead, and is demonstrated to work well in practice. The paper also discusses the rendering of selectively refined meshes, including the generation of triangle strips for efficient rendering. It also presents results for various applications, including terrains, parametric surfaces, and general meshes. The framework is shown to be effective in reducing the computational load and improving the performance of real-time rendering of complex geometric models.