3d Virtuality Sketching: Interactive 3d Sketching Based on Real Models in a Virtual Scene
Proceedings of the 5th Annual Conference of the Association for Computer Aided Design in Architecture (ACADIA)
Sketches and working models are without doubt one of the most widely used tools in the architect's repertoire. In the early phases of the design process in particular, they represent an essential part of the exploration process. For the most part, however, sketching and model building are separate and sequential steps. This paper examines how both media can be linked to each other more effectively so that the design process is more continuous and the transition between the two media more fluid.
... Using a multitouch table with additional 3D real-time object recognition, a prototypical system was developed and realized as part of a research project in which an interactive 3D sketching tool was linked with a real 3D working model. // Performative Geometries ACADIA 2012 // Synthetic Digital Ecologies 410 411 // Emerging Interfaces ACADIA 2012 // Synthetic Digital Ecologies 410 411 Table 1: Comparison of freehand sketch and model Freehand Sketch Working Model 2D 3D Quick and flexible Better spatial impression Can represent any scale Can be explored and revised with both hands Tactile feedback The differences noted here are actually qualities that speak for one or the other tool, and if one looks closely it is apparent that they hardly relate to one another. Although both tools are used in the design process, they are rarely used in combination. As a result, switching between the different media interrupts the design process and creative workflow. This research project takes this as its starting point and examines the possibilities offered by linking the sketch to the working model with the help of computer technology. The aim of this project is to connect existing and established design tools with a view to optimizing the use and advantages of both. THE SKETCH Freehand sketching is a design method that has been widely used for hundreds of years, and more so than perhaps any other method. Its popularity is, of course, not a coincidence but rather a factor of its special qualities. Fish and Scrivener list four important attributes of sketches (Fish and Scrivener 1990). Of particular interest are the ability to depict abstractions at different levels (Cross 2008), to embody indeterminacy (Buxton 2007), and with it to allow ideas to emerge-these are among the most fundamental attributes of a freehand sketch. But why is this? In the early design phases, the information available is often vague and incomplete. The ideas that float around in the designer's mind are not yet well formed. A design tool needs to be able to accommodate these kinds of imprecise thoughts and vague information. This is essential for a dialogue between the designer and the drawing to arise, which in turn serves as a basis for refining and developing the idea. Closely related to this is the concept of emergence. The term emergence describes the process of making qualities and things visible that cannot be explicitly formulated or depicted (Gero, Damski, and Han 1995) . In the context of designing, this is essential as it helps designers to perceive something in a drawing that may not be what they originally drew. The sketch as a design tool and its capacity to accommodate emergence represents a catalyst for stimulating not yet conceived interpretations of an idea put down on paper (Buxton 2007) . This applies particularly when drawing on top of existing images, renderings, and sketches. In contrast to a sketch drawn on an empty piece of paper without any reference image, drawing over existing sketches stimulates the process of emergence-and therefore visual thinking-much more strongly. The combination of image and sketch, in particular, can bring forth entirely new forms resulting in the emergence of new ideas and inspiration. USER SCENARIO: AN URBAN DESIGN COMPETITION An architect is tasked with developing a design for an urban environment. Rather than working onscreen with a mouse and keyboard, he or she uses a large multitouch table equipped with real-time object recognition that will "see" the objects in the model. To begin with, a site plan of the competition site and surroundings can be seen on the table. The architect begins by cutting blocks to size out of a material of his or her choice for use with the model so that the positioning of approximate building volumes can be tested. After some experimentation, the architect settles on a first potential constellation. The next step is to examine how the vertical articulation of the blocks and facade design will influence the design. The architect places a SpaceMouse with a camera symbol on the multitouch table, and an "ego perspective" of the design idea appears on a touch screen arranged next to the model (3Dconnexion). He or she positions the