The virtual reality (VR) is an environment, which enables the proactive participation of the customers in defining their needs and requirements within the product development process. However, the traditional approaches for representation of physically existing objects (products) using VR show only a few of their properties (geometric, structural, and topological). The potential of VR as technology for efficient validation of still not-materialized artifacts in the early design stages is not fully exploited. In order to improve the immersion and to enable customers in configuring more aspects of the newly created customized products, as well as to validate these through "experiencing," we propose the concept of so-called implicit features representing "hidden" product properties (i.e., magnetization, surface roughness, and humidity), which normally are not part of the object model, cannot be perceived directly, and are not exposed for configuration. Here, we discuss the implicit feature concept, their implementation, and their use for customer co-design.