Computer Aided Design (CAD) applications have become designers inevitable tools for expressing and simulating innovative ideas and concepts. However, replacing traditional materials and mock-ups with 3D CAD systems, designers are faced with the intangibility problem. As a touchable and graspable interface based on 3D CAD data, we proposed Augmented Foam, which combined Augmented Reality technologies and physical blue foam with little additional effort. Using Augmented Foam, blue foam mock-up is overlaid by a 3D virtual object, which is rendered with same CAD model used for mockup production. In order to solve the visibility problem between the reviewers hand and the virtual object, we implemented a hand detection and separation. Augmented Foam was tested for a cleaning robot design. Twenty participants were asked to evaluate the perceived visual reality of product appearances for 6 design simulation techniques including Augmented Foam. We found that the participants perceive the shape, size, and color of product appearance more accurately than renderings on CRT, traditional Augmented Reality, and a foam mock-up.