Visual Interfaces for Solids Modeling
This paper explores the use of visual operators for solids modeling. We focus on designing interfaces for free-form operators such as blends, sweeps, and deformations, because these operators have a large number of interacting parameters whose effects are often determined by an underlying parameterization. In this type of interactive modeling good solutions to the design problem have aesthetic as well as engineering components. Traditionally, interaction with the parameters of these operators has been through text editors, curve editors, or trial-and-error with a slider bar. Parametric values have been estimated from data, but not interactively. These parameters are usually one- or two-dimensional, but the operators themselves are intrinsically three-dimensional in that they are used to model surfaces visualized in 3D. The traditional textual style of interaction is tedious and interposes a level of abstraction between the parameters and the resulting surface. A 3D visual interface has the potential to reduce or eliminate these problems by combining parameters and representing them with a higher-level visual tool. The visual tools we present not only speed up the process of determining good parameter values but also provide visual interactions that are either independent of the particular parameterizations or make explicit the effect of the parameterizations. Additionally, these tools can be manipulated in the same 3D space as the surfaces produced by the operators, supporting quick, interactive exploration of the large design space of these free-form operators. This paper discusses the difficulties in creating a coherent user interface for interactive modeling. To this end we present four principles for designing visual operators, using several free-form visual operators as concrete examples.