A projection augmented model (PA model) is a type of haptic augmented reality display. It consists of a real physical model, onto which a computer image is projected to create a realistic looking object. Thus, a PA model creates the illusion of actually being the object that it represents, as opposed to a white model and a projected image. Users can physically touch the surface of a PA model with their bare hands, which has experiential value for the types of applications for which they are being developed. However, the majority of PA models do not provide haptic feedback for material properties such as texture, and hence feel incorrect when they are touched. In addition, most PA models are front-projected which means the projected image appears on the back of the user's hand, and their hand casts a shadow on the display. Previous research has found that touching this type of PA model reduces a user's sense of object presence. The empirical study reported in this paper investigated which of the problems had a greater effect on object presence. It was found that object presence was significantly higher when correct haptic feedback for material properties was provided; however eliminating the visual projection problems rarely affected object presence. These results have implications for the direction in which PA model technology should be developed. They also have implications for theory on how the haptic and visual senses contribute to a person's sense of object presence, and indeed presence.

A projection-augmented model is a type of nonimmersive, coincident haptic and visual display that uses a physical model as a three-dimensional screen for projected visual information. Supporting all physiological depth cues and two sensory modalities should create a strong sense of the object's existence. However, conventional measures of presence have been defined only for displays that surround and isolate a user from the real world. The idea of object-presence is thus suggested to measure “the subjective experience that a particular object exists in a user's environment, even when that object does not” (Stevens & Jerrams-Smith, 2000). A correlation study was conducted to demonstrate the reliability and validity of objectpresence as a construct. The results of a modified Singer and Witmer Presence Questionnaire suggest the existence of a reliable construct that exhibits face validity. However, the Presence Questionnaire did not correlate significantly with a user's tendency to become immersed in traditional media, which would support the assertion that this construct was object-presence. Considering previous work, the results of the current correlation study exhibited a pattern evident in previous studies of presence suggesting that object-presence and presence could be gender biased by the task to be completed or by the presence measure.