New System Specification and Architecture
According to the issues described in the previous Section, the system will have to comply with the following general specifications:
- • it has to be low cost, so as to be affordable for a large number of design studios or even for single designers;
- • it has to be in a desktop and portable version. This is because it will ease the introduction of the system in the everyday working life as it happens for a mouse or a keyboard;
- • it has to be compliant with as many commercial software applications for surface modelling as possible;
- • it has to be modular, so as to be customized according to the kind of surfaces with which the designer and/or the design studio usually deals;
- • it has to be performer in terms of the potentiality of representing a surface. Indeed, the system has to be able to render tridimensional surfaces with curvature radii lower than 40 mm. This will be an improvement compared with the devices that are currently available.
In order to satisfy the system requirements, we have decided to develop a system that takes cues from the know-how acquired with the development of the SATIN system with regard to the modalities of interaction with the virtual surface. In fact, the system developed is of type “free hand”. This device is able to modify its shape so as to mimic the shape of the surface to represent. Consequently, it enables the users to choose where to freely explore the virtual surface through the sense of touch, as it commonly happens with a real object. For this reason we decided to use the strip approach which has proven to be effective. Starting from this approach, we have developed a compact and desktop tactile display that can be placed in a traditional office, such as on a desk. It embeds all the hardware necessary for its working, and
Fig. 3.8 System architecture and data flow only needs to be connected to a power source and to a PC or laptop via the dedicated USB connection.
For what concerns the visualisation system we have decided to implement a solution based on the Augmented Reality technology. Thanks to this technology, it is possible to superimpose the 3D virtual model of the surface onto the tactile display. This technology also allows us to limit the cost and the size of the whole system as required by the given specifications.
As shown in Fig.3.8, the designer has the possibility of choosing which part of the surface to represent. The data required to perform tactile and visual rendering are processed by a dedicated software module installed on a common personal computer or laptop. All these pieces of information are used to compute the position of the control points that are sent to the tactile display by means of serial signals. In the meantime it is possible to use these data to generate the 3D model, which is used by the visualisation system.