Multi-level of detail models for reverse engineering in remote CAD systems

This paper proposes a multi-level CAD system based on remote Reverse Engineering (RE). At the core of the system is an advanced multi-Level Of Detail (LOD) representation for remote CAD systems. The LOD is represented through hierarchical nested bi-variant surfaces. With the proposed multi-level approach, the entire RE takes tens of seconds for tens of thousands of sampled points. Results for the LOD extraction stage (RE and modeling) were faster, with an order of seconds rather than the tens of seconds achieved by other systems. The advantages of the proposed LOD method include the following: (1) due to multiresolution capabilities, an object can be directly and robustly modeled from sampled data, in real-time at different levels of details; (2) local or global error control can be applied according to an error estimator at each node. Therefore, the geometric details can be preserved even at a low level of resolution; (3) selective refinement can be applied by modifying selected areas at different levels of detail. Therefore, an object can be modeled with rough, fine or mixed detail resolution; (4) multi-level meshing can be performed according to color or texture criteria that are independent of the geometry criteria.