The topic of this master’s thesis is on the effects of rapid prototyping technology in the product concept design process. The research material includes six themed interviews with experts in the rapid prototyping technology field, a product design project and survey with a client company. The main goal of the work is to identify the impacts that rapid prototyping technology creates for the design practitioner in the concept design working environment. A secondary target is to explore the effect of rapid prototyping technology in the Light Capturer design project. The perspective of this thesis is industrial product design and different design process models and working procedures are presented. As background, an overall view of rapid prototyping technology both in the industrial design world and on a societal level are included. The thesis utilizes qualitative and empirical methods. A primary analysis approach used is thematic analysis with themes and sub-themes, which are then reflected against the product designer’s concept design process and feedback from client company stakeholders. The results of this evaluation have been collected together in a research summary where the results are examined against the established conventions of product design theories. The design project part of the thesis follows the design process of the Light Capturer product concept. The aim of the project was to create a prototype of the concept using rapid prototyping technologies. The design process consisted of five different phases separated by review meetings with the client company. The results of this thesis claim that the effects of rapid prototyping technology can be seen in Actor-, Action- and Tool-types in the environment of the product concept design process, but only by the actors of the process. However, the designer is not the only important actor of the equation. Rapid prototyping technology also creates effects for other participants of the process. The value and impact of the effects are evaluated by founded themes and sub-themes within this master’s thesis.