Christine Chevrier

Parametric Documenting of Built Heritage: 3D Virtual Reconstruction of Architectural Details

This paper examines 3D modelling of architectural elements with the help of parametric components. Such components may be useful within the framework of projects dealing with virtual 3D reconstruction of heritage monuments. Architectural components of the built heritage often have complex geometry. We studied the various geometrical shapes of a given architectural element, representative of a specific period and place. This study allowed us to identify the parameters and to implement parametric objects (in Maya Environment [1]). We also developed a Graphical User Interface (GUI) to answer the users needs while generating the 3D model representing the architectural element. Within this GUI, the user is able to make adjustments with the help of laser point clouds from laserscanning, 2D plans or photographs. We exemplify our method with a case study dealing with openings and lintels. The corpus under study consists of elements of the built heritage of Montreal (Canada) and Nancy (France).

Reverse engineering of scale models using dataflow programming: Application to the fortification of plans-reliefs

Despite the progress in three-dimensional scanning, some architectural artifacts remain a digitizing challenge. Scale models and more especially the plans-reliefs of Louis XIV of France have specific characteristics such as size, scale, number, etc. A knowledge-based modeling approach is developed to address the limitations of digitizing tools. Our study deals with the fortified areas of the scale models. Bastioned fortification works extend over wide areas but they are built according to design rules. Once studied and organized, fortification knowledge has been used to create a library of parametric components. Implemented in Grasshopper, the components were manually adjusted to different practical cases. The library was then validated and we are now focusing on the automation of the adjustments of the components. Thereupon a reverse-engineering approach has been set up. Semantic segmentation algorithms have been defined and implemented in Grasshopper to automatically extract fortification features from 3D surveys based on the knowledge of fortification design rules. Along with the three-dimensional modeling of fortification, an automatic reconstruction of the city parts of the scale models is underway. Both these studies are part of a project aimed at valorizing and diffusing a very unique cultural heritage collection. As such, knowledge models are precious assets both the digitizing and the semantic enhancements of the final application.

3D semantic modelling of scale models from 2D historical plans

The French collection of Plans-Reliefs, scale models of fortified towns, are an exceptional architectural heritage. Many cities, represented on these plans-reliefs, would like to expose, develop and exploit this historical knowledge. However, the fragility, the dimension of the supports and the exposure conditions make this acquisition difficult. Thus, the creation and the exploitation of a virtual model is an interesting alternative. This paper presents a new method exploiting historical documentary for the 3D semantic modelling of Plans-Reliefs as more than the half physical Plans-Reliefs are currently enclosed in containers in Paris. From 2D plans, ground outlines and facades of buildings are partially-automatically extracted to create automatically the 3D textured model of each building and ground elements (streets, rivers and courtyards). Another specificity of the method is the use of graphical schemes for the description of parametric objects.