Stefano Girardi

Detailed 3D Modelling of Castles

Digitally documenting complex heritage sites such as castles is a desirable yet difficult task with no established framework. Although 3D digitizing and modelling with laser scanners, Photogrammetry, and computer aided architectural design (CAAD) are maturing, each alone is inadequate to model an entire castle in details. We present a sequential approach that combines multiple techniques, each where best suited, to capture and model the fine geometric detail of castles. We provide new contributions in several areas: an effective workflow for castle 3D modelling, increasing the level of automation and the seamless integration of models created independently from different data sets. We tested the approach on various castles in Northern Italy and the results demonstrated that it is effective, accurate, and creates highly detailed models suitable for interactive visualization. It is also equally applicable to other types of large complex architectures.

3D modeling of complex and detailed cultural heritage using multi-resolution data

The article reports the interdisciplinary project of the virtualization of the Great Inscription of Gortyna, Crete, for 3D documentation, structural studies, and physical replica purposes. The digitization of the longest epigraphic text of the Greek civilization (6 m long and 1.75 m high, with approximately 2--3 mm-depth engraved letters) and its surrounding heritage area (around 30 × 30 m), required long planning and the construction of a dedicated acquisition system to speed up the surveying time, limited to few hours per day. Primarily, range sensors were employed in a multi-resolution way, digitizing detailed parts in high resolution and less smoothed areas with lower geometric resolution. Some selected areas were also modeled with our multiphoto geometrically constrained image matching approach to demonstrate that the same accuracy and details can be achieved using either scanners or photogrammetry. The derived 3D model of the heritage is now the basis for further archaeological studies on the incision techniques and a deeper structural analysis on the monument. The challenges of the work stay in the acquisition, processing, and integration of the multi-resolution data as well as their interactive visualization.

Multi-resolution modeling of complex and detailed cultural heritage

The article reports the interdisciplinary project of the virtualization of the Great Inscription of Gortyna (Crete) for 3D documentation, structural studies and physical replica purposes. The digitization of the longest epigraphic text of the Greek civilization (6 m long and 1.75 m high, with ca 2-3 mm depth engraved letters) and its surrounding heritage area (ca 30 x 30 m), required a long planning and the construction of a dedicated acquisition system to speed up the surveying time, limited to few hours per day. Primarily range sensors were employed in a multi-resolution way, digitizing detailed parts in highresolution and less smoothed areas with lower geometric resolution. Some selected areas were also modeled with our multi-photo geometrically constrained image matching approach to demonstrate that the same accuracy and details can be achieved using either scanners or photogrammetry. The derived 3D model of the heritage is now the basis for further archaeological studies on the incision techniques and a deeper structural analysis on the monument. The challenges of the work stay in the acquisition, processing and integration of the multi-resolution data as well as their visualization.

Digital documentation of complex architectures by integration of multiple techniques: the case study of Valer Castle

The digital documentation of monuments and architectures is an important field of application of the 3D modeling where both visual quality and precise 3D measurement are important. This paper proposes an integrated approach based upon the combination of different 3D modeling techniques for the virtual reconstruction of complex architectures like those found in medieval castles. The need of combining multiple techniques, like terrestrial laser scanning, photogrammetry and digital surveying comes from the complexity of some structures and by the lack of a single technique capable of giving satisfactory results in all measuring conditions. This paper will address modeling issues related to the automation of photogrammetric methods and to the fusion of 3D models acquired with different techniques, at different point densities and measurement accuracies. The test bench is a medieval castle placed in Trentino A.A., a tiny region in Northern Italy.

LATE TRIASSIC (EARLY-MIDDLE CARNIAN) CRUROTARSAN TRACKS FROM THE VAL SABBIA SANDSTONE (EASTERN LOMBARDY, BRESCIAN PREALPS, NORTHERN ITALY)

A new Late Triassic tetrapod tracksite was discovered north of the Zone village, on the north-eastern side of the Iseo Lake (Southern Alps, Brescia, Lombardy). The tracks are preserved on two distinct bedding planes, belonging to the lower/middle Carnian Val Sabbia Sandstone. The ichnoassemblage is composed of about seventy footprints, organized in six quadrupedal trackways exhibiting both wide and narrow gauge. All the trackways can be attributed to a crurotarsan archosaur trackmaker and at least three of them could be assigned with confidence to the ichnogenus Brachychirotherium Beurlen 1950. If we exclude a dubious Brachychirotherium specimen track from Mt. Pelmetto (Dolomites), the Zone material represents the first well documented report of this ichnogenus from the Upper Triassic of Northern Italy. The footprints have been analyzed both with traditional methods, and with 3D technologies, such as the terrestrial laser scanner. The ichnoassemblage, although not exceptionally preserved, adds new important data for the stratigraphic distribution of crurotarsan tracks in the Triassic of Southern Alps.