/ The Yingzao fashi project / Teaching materials / Coursework / Reaction / Papers / Who's who / Related sites /

                         / Title page / Introduction / Approach / Assignments / Findings and discussion / Conclusion / Notes & References /

Representation of the virtual model

In the building assignment (1994-95), students found it difficult to manipulate the elements of the model; they found it especially difficult to select individual points, lines, and other elements. This resulted from the inconsistency between the three-dimensional virtual model and the two-dimensional representation of that model on the screen. We, the instructors, tended to think in terms solely of the three-dimensional model, but in fact what the students saw and manipulated was its two-dimensional representation: the interface mechanism between the user and the virtual model consists of a two-dimensional monitor display and a two-dimensional pointing device.

We propose two approaches to investigate this question of the interface of the virtual model. The first approach is to redesign the existing interface to support the required operations. The present version of the model kit, used in the faŤade assignment (1995-96), incorporates such an improved interface: it includes self-aligning functions and a graphical menu template.

The second, more radical, approach is to transfer the model kit to a virtual reality simulation environment. In another project, we are currently developing the virtual reality interface technology, including stereographic eyeglasses with head tracking and a three-dimensional mouse with object manipulation commands. In the virtual reality environment, students will be able, by means of a stereographic display and eyeglasses, to enter the three-dimensional virtual space containing the model kit and to manipulate the model parts directly. This would eliminate the problem of manipulating two-dimensional representations of three-dimensional objects.

The philosophy of the modelling environment: an observation

In the building assignment, it appears that the students were reacting to the philosophy of the modelling environment, which, by attributes like its characterization of three-dimensional space and the commands it provides, makes some tasks easy and others difficult.

Most students chose variants which could be constructed easily and avoided those that could not. Students constructed the "easy" variants by first forming a single bay and then applying commands like copy, array, and mirror to form the complete structural frame. These models were generally large and repetitive.

Only a few students opted for the "difficult" variants, which required intensive manipulation of individual components. These models were small, but involved subtle issues, like the structural frame's deviations from orthogonality, for which the Yingzao fashi has explicit provisions. (We had omitted these provisions from the assignment for the sake of simplicity.)

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