Keywords

1 Introduction

The Czech Republic is a country famous for its majestic castles, well-preserved châteaux and their beautiful interiors and for its crumbling ruins inviting us for strolling through them. The 2D and 3D technologies are used for re-constructing and preserving these monuments. The 2D technologies are most frequently used for digitalization of archival documents, they are also used when preparing documentation for 3D virtual reconstructions of historical sites.

Another convenient use of the created 3D digital models is their inclusion into an interactive application, which then mediates information on historical and architectonic development of objects. In the Rotunda project, which is a part of the second author’s dissertation thesis, we focus on the implementation of these models into a serious game suitable for elementary school pupils. Such a kind of interconnecting of technologies and ways of teaching is very attractive for these i-kids (cf. [1, 2]). A very thorough analysis was essential when the final choice of the 3D program convenient for the 3D models creation was being made.

The aim of the paper is to introduce a possible way for selecting a 3D software appropriate for creation of a digital 3D model of a historical building.

2 Background

2.1 The 3D Technologies

The 3D or three-dimensional technologies belong to quite an extensive sphere of ICT. As the term itself hints, they involve width and height and also depth; they work with these three dimensions’ space. A brief outline of their basic division is given below (see [3]).

  • Digitizing tools

    • 3D scanning

    • Photogrammetry

  • Modelling technologies

    • CAD and CAD/CAM systems

    • Parametric systems (so called parametric modeller)

    • BIM systems

    • software for post-processing

    • Polygonal systems (so called free modellers)

    • Animation software

    • Game engine

  • 3D print

  • Virtual and augmented reality

2.2 3D Modeling

3D modelling is a process during which a virtual spatial model is being created on the basis of certain template. This template can have the form of scheme documentation, photographs, pictures, vedutas, or just a written or oral description. In this way it is possible to reconstruct the earlier form of the chosen template and also its historical development. If this method is applied, also a simplified image of an object (even with important elements highlighted) can be created in a relatively short time. In case of building monuments, modelling on the basis of the scheme documentation and construction-historical research is applied. If such a kind of documentation is not available, then modelling is based on photographs and sketches (if there are some) and on written and oral descriptions. In case of historic buildings which no more exist or which have been damaged too much, the 3D modelling is the only possibility of digitalization or the only possibility of reconstruction (if a paper model variety is ignored). Most frequently, castles’ or forts’ ruins are concerned whose walls’ remains do not exist anymore, or places at which the original historic building has been replaced by other building development. Then a virtual 3D modelling can be carried out merely on the basis of extant historical sources, such as vedutas and descriptions of the buildings presented in documents from the given time period, and also on the basis of analogies with still existing buildings of the same type.

If the 3D modelling is to be carried out, it is essential to select an adequate software. The amount of the 3D modelling tools available on market is enormous. The following chapter outlines the basic criteria for selecting a software suitable for the 3D modelling of historic building monuments.

3 3D Modelling Software and Its Selecting Criteria

Being aware of a big amount of the 3D software available, we could come to the conclusion that the 3D programs designed for architects and builders (e.g. ArchiCAD or Autodes Revit) are suitable for digital reconstruction of historical buildings. However, it is necessary to realize that these modelling tools are designed for the current architecture which is based on simple geometrical shapes. The current architecture is plane, full of pure lines and without “useless” decorative elements. On the contrary, historical buildings have a lot of decorative elements, internal and external vaulted arches, frequent irregularities (especially in case of castles, forts and similar types of buildings). Then it is obvious that the 3D programs designed for builders and architects are not convenient for modelling of historical buildings.

On the contrary, programs designed for polygonal graphics, which are primarily developed for entertainment industry, in which irregularities and decorative elements are “not missing”, offer suitable solutions. We are talking about the 3D modelling programs which do not work with precise parameters (like CAD or parametric systems) but focus on possibilities of comfortable creating of complicated and non-typical shapes. The most important issue about the digital reconstruction of historical buildings which is carried out through the 3D modelling is the resulting form. The virtual model of the given historical building should be as close to the original form as possible, it needn’t be “millimetre-precise”.

3.1 Selecting Criteria

  1. (a)

    Licence

  2. (b)

    Gallery of tools and options of additional modules

  3. (c)

    Import and export options

  4. (d)

    User comfort

Licences

It is essential to obtain the licence of a software which has been chosen as convenient since not only the criteria (b) and (c) are impacted by this issue, but also for example using of the created models (especially in the sense of commercial/non-commercial).

Programs with the OpenSource licence are available free of charge even if used for commercial purposes.

Paid professional licences are related to professional programs. Concerning the financial demands, some companies offer various versions of their paid software – the lite version, in which mostly just basic or the most frequently used tool are available or in which not all the transfer formats are supported; the full version without plug-in modules, which can be, however, additionally purchased; and the complete version. If the institution involved in care of the given building monument is an educational institution or if it closely cooperates with and educational institution, an education (edu/student) licence can be considered.

Galleries of tools and options of additional modules

It can be generally claimed that the range of modelling tools and possibilities of their extension through plug-in modules (plug-ins) depend on the licence of the chosen software. This choice is connected mainly with the user’s “professional level” and the needed detailed preciseness of the processing of the 3D model. It is obvious that the extent of the galleries of the 3D software tools for complete beginners (which are generally free or very lowly charged) will be different from the extent of a fully professional OpenSource licensed software program. And obviously, it is important to know what the modeller will focus on and how much detailed 3D models s/he will want to create. If s/he wants to create simple models, then the basic tools will be sufficient, in case of creation of 3D models processed in detail, the extended gallery of tools will be needed.

Options of import and export

For further work with the 3D model or potential inclusion of another (already created) model into the setting, formats for data transfer are needed – those for both the data imported and the data exported. Therefore, it is important to consider which input data will be processed and which further operations will be carried with the model, that means the purpose of the designed 3D model, its inclusion into the interactive application, additional elements of the 3D model created by other technologies, etc.

If the chosen 3D modelling software does not support the needed import or export format, other software can be used for the format conversion. This “intermediate stage”, however, increases the risk of damaging or unwanted deforming of the converted 3D model, including the texturing or animation.

User comfort

If more software applications are available, then obviously the one which is the closest to and the most convenient and pleasant for the user is chosen.

3.2 Case Study – Project Called Rotunda

Within the framework of the second author’s dissertation thesis, the Rotunda project is carried out. This project focuses on creating of a 3D model of a church historical building and its implementation into a teaching game designed for elementary school pupils. The game is implemented into the process of teaching historically oriented subjects, and its impact on the educative process is being researched. Recent research has shown that serious games included into educational process have positive effects on students learning and their motivation (see [4–8]).

The Rotunda project is being carried out at a university, therefore the choice of a convenient program was limited merely on a 3D software with the education (student) version licence type.

The costs and the licence policies having been compared, four programs were put on the short list: Blender with the OpenSource licence, CINEMA 4D by German MAXON, which offers two types of edu/student version licences (one is completely free of charge, the other one is paid), and the Autodesk company’s programs MAYA and 3DS MAX with the edu/student version licences.

Table 1 illustrates suitability of the given software for the Rotunda project.

Table 1. Comparison of the licence policies of the selected 3D software.
Full size table

The range of tools and options of additional modules depends on the “professional level” of the selected 3D software and on the type of the selected licence. The licence impacts on the range of the gallery of tools are shown in Table 1.

Considering the supposed implementation of the model into the serious game, the import and export option criterion was very important for the Rotunda project. Three out of the above given 3D software were evaluated as convenient. The only unacceptable software was Maya, in case of which Maya plug-in must be installed for supporting the import from and export to other formats, and even then the given 3D model has to be adjusted to a format supporting the Maya.

Taking into account the user comfort which was the most convenient for her, the modeller chose the 3DS MAX (edu/student version) software by Autodesk company, see Table 2.

Table 2. Brief comparison of criteria.
Full size table

4 Conclusion

The main objective of this paper was to present the basic criteria for selecting a convenient 3D modelling software appropriate for creation of a digital 3D model of a historical building. On the basis of our experience with the Rotunda project we can confirm that when selecting a 3D software according to the given selecting criteria, it is necessary to take into consideration the reason and purpose of getting and using of the virtual 3D model. Other factors to be considered are the institution’s technological and financial possibilities.

One of numerous possibilities of using ICT in education was another issue outlined in the paper. Within the framework of a dissertation thesis, using of a serious game in the process of teaching history at elementary school is being observed. Specifically, the most interesting issues for us are the impact on communication between a teacher and his/her pupil (cf. [9, 10]), and the impact on pupils’ activation and motivation (see [11]) which are brought if serious games are applied through interactive boards. The 3D digital models implemented into serious games can be used in the teaching process but they can be also placed into permanent expositions of historic objects and this way they can offer a new kind of insight into history to the visitors.