The deliverable for Reverse engineering can take many forms. Primarily driven by how the end user intends to apply the data, we use 4 categories to classify the end deliverable:
The mesh is closest to the original scan data and represents the object which has been measured most accurately. This is useful if the data needs to be used as is. With the advent of 3D printing a pathway straight from scanner to manufacturing exist. Although meshes are typically not well suited to be manipulated in traditional 3D CAD systems, dedicated software for mesh manipulation has made is possible to forgo CAD and make changes were needed.
Nurb surfaces a mathematical approximation of a scanned data set. As the surface is approximated by a set of splines, the representation is more efficient and the file-sizes are typically much smaller. Nurbs surfaces can be readily imported in 3D CAD programs like Unigraphics and Solidworks, as well used as input for CNC programming packages. A growing use is the use of scan derived nurbs surfaces for CFD analysis and FEA, allowing to analyze models of components “as manufactured” instead of “as designed”.
When creating a model from a mesh or surfaces, the model does not contain any information what different sections represent. This means a cylinder will not be recognized as such, neither other entities like planes and cones. The model will have also all the flaws of the manufacturing process in it, which means a plane and cylinders are not perfectly straight, might have dents and bumps, etc. If the goal is to correct for imperfections, then features need to be created which replace the original mesh.
In instances where one is interested in a limited amount of features of a scan, but does not want to recreate the complete model as such, it is possible to follow a hybrid approach, and only create features where needed and represent everything else as surfaces. Examples are castings, where only the machined surfaces will be re-created as features.
