A Geometric Processing Workflow for Transforming Reality-Based 3d Models in Volumetric Meshes Suitable for Fea

Abstract

ABSTRACT:Conservation of Cultural Heritage is a key issue and structural changes and damages can influence the mechanical behaviour of artefacts and buildings. The use of Finite Elements Methods (FEM) for mechanical analysis is largely used in modelling stress behaviour. The typical workflow involves the use of CAD 3D models made by Non-Uniform Rational B-splines (NURBS) surfaces, representing the ideal shape of the object to be simulated. Nowadays, 3D documentation of CH has been widely developed through reality-based approaches, but the models are not suitable for a direct use in FEA: the mesh has in fact to be converted to volumetric, and the density has to be reduced since the computational complexity of a FEA grows exponentially with the number of nodes. The focus of this paper is to present a new method aiming at generate the most accurate 3D representation of a real artefact from highly accurate 3D digital models derived from reality-based techniques, maintaining the accuracy of the high-resolution polygonal models in the solid ones. The approach proposed is based on a wise use of retopology procedures and a transformation of this model to a mathematical one made by NURBS surfaces suitable for being processed by volumetric meshers typically embedded in standard FEM packages. The strong simplification with little loss of consistency possible with the retopology step is used for maintaining as much coherence as possible between the original acquired mesh and the simplified model, creating in the meantime a topology that is more favourable for the automatic NURBS conversion.

Stability analysis of leaning historic masonry structures

“…In the latter case, the watertight mesh is processed by means of a retopology algorithm (see for example [51]) to generate a coarser representation of the surface [52]. This kind of algorithms are able to re-mesh a surface into a triangular mesh, with a certain resolution chosen by the user, using unified local smoothing operators that optimize both the edge orientations and vertex positions in the output mesh [51].…”

Integration of a Wearable Mobile Mapping Solution and Advance Numerical Simulations for the Structural Analysis of Historical Constructions: A Case of Study in San Pedro Church (Palencia, Spain)

“…This method transforms the point cloud into a solid model by means of voxel elements. Another recent method is the approach proposed by Gonizzi et al [13]. This approach is based on the use of a retopologization of the mesh, allowing to create as-built CAE models.…”

Method for 3D City Building Continuous Transformation Based on an Improved LOD Topological Data Structure

“…In research on 3DCM, great progress has been made on the technology of large-scale terrain continuous LODs based on real data. Many continuous LOD algorithms based on regular grids have realized the real-time display of large-scale terrain [17][18][19][20][21]. However, the research of continuous LOD technology for buildings is still in its infancy.…”