Recording 3D data for monuments or larger volumes: introduction

Authors: Stefan Lindgren and Carolina Larsson - Last update: 2023-09-27

Introduction

Before embarking on a 3d-documentation project it is necessary to plan the acquisition properly and one easy way to start is to ask the question: "What should the final result be used for?" The answer to that question is very useful to decide exactly what needs to be done during the acquisition. For example, if the purpose of the recording is to create a downscaled model for 3d-printing, it is not necessary to use high resolution scanning and color acquisition. But if it is needed for analyses of toolmarks and colors, then high resolution in the recording and good quality color acquisition is necessary. These two different examples would demand different workflows, even though they both technically are recordings of 3d data.

There could of course be a wide range of uses for a 3d-model. For example: general documentation as part of a larger acquisition, reference for reconstructions, analysis, visualizations, which in turn could be divided into: 3d-printing, rendering of high resolution 2d-images, 3d-modells online or maybe for games and gameengines. With this in mind, it is hard to cover 3d recording for all different possible uses of a 3d-model in one document. This documentation will try to cover the more common situations, but it is by no means complete.

The documentation will cover:

1. Basic 3d-scanning with a terrestrial 3d-scanner

2. 3d-recording using photos

3. Combining 3d-scanning and photos

Throughout this documentation a casestudy will be used to exemplify different situations. It is a ruin of a church from south of Sweden in a place called Rya. This was 3d-documented using different technologies and instruments. The 3d-scans were done with a large overlap between them, so they can be aligned without any extra instruments. However, markers were used and measured, but mainly for the photographic postprocessing.

The specific instruments are not important when it comes to describing the methodologies, since different makes of the instruments produce similar results. There will be examples in the tutorial that use specific instruments and software, in those cases, the make, model and version of the instrument or software will be mentioned.