Volumetric Shapes Research Articles

Volumetric Shapes of Solids of Revolution from a Single-View Range Image

Volumetric Shapes of Solids of Revolution from a Single-View Range Image

Visual search for simple volumetric shapes.

Five experiments measured reaction time (RT) to detect the presence or absence of a simple volumetric shape (target) dependent on the number of display items (distractors) and their depicted three-dimensional (3-D) orientation. Experiments 1-4 examined every pairwise combination of two different simple volumetric shapes in two 3-D orientations. Conditions exhibiting "pop-out" could be predicted by differences in their two-dimensional (2-D) features. Conditions in which search was slower support previously found search asymmetries for particular 2-D features. When the distractors were a mixture of the other shapes in the same 3-D orientation, search was serial, except when the target had a curved principal axis (Experiment 5). The results suggest that these simple volumetric shapes are not processed preattentively.

Expert form feature modelling shell

Contemporary geometric modellers are unsuitable for mechanical design because of mismatch in abstraction level. The databases of these modellers cannot be used to drive automated applications such as engineering analysis or process planning because of missing product information. The paper outlines an integrated system for design and applications; the system reasons in terms of form features. Object-oriented programming techniques support user definition of form features (volumetric shapes) that may be positioned and manipulated in a logical manner. A solid modeller interface generates equivalent solid representations in parallel with feature representations. Mechanisms for parameter inheritance and validity checking (cognition) are also discussed. The system is modular, which will allow it to be integrated with tolerance and material modellers that are currently under development. Artificial intelligence techniques have been applied to solid modelling, resulting in this powerful feature technology for creating flexible and integrated CAD systems for the next generation of engineering tools.