Perceiving transparency from opaque surface materials.

It is easy to marvel at the abilities of master painters and sculptors to depict draped cloth, especially in comparison with lesser artists whose depictions of cloth may often appear not quite right. Draped cloth is difficult to represent because its visible appearance is influenced by many factors, including the properties of the cloth itself (e.g., its thickness and stiffness) and also the shape of the object over which it is draped. The depiction of transparent cloth is even more difficult, because the artist must convey the impression of two distinct surfaces (Fig. 1, Left ). Painters are able to manipulate color and shading to achieve that effect, and the perceptual consequences of those manipulations have been studied extensively (1⇓⇓–4). However, those tools are not available to sculptors. The appearance of transparency in a sculpture must be based entirely on the three-dimensional (3D) shape of the sculpted object. The article by Phillips and Fleming (5) on “The Veiled Virgin illustrates visual segmentation of shape by cause” is a scientific investigation of how human observers are able to interpret the presence of transparency in solid shapes composed entirely of opaque materials. Fig. 1. Images of objects with draped cloth. ( Left ) A sculpture of The Veiled Virgin by Giovanni Strazza, which appears as a human face with a transparent veil draped over it. ( Right ) A computer simulation of a sphere with an opaque cloth draped over it. Note, in both cases, that it is possible to determine which regions are in contact with the underlying object and which ones are not. One of the central hypotheses that guided this research is that the shape of an object can provide information about the morphogenic processes with which it was created. This idea was first proposed over a century ago by the … [↵][1]1Email: todd.44{at}osu.edu. [1]: #xref-corresp-1-1