The use of Building Information Modeling (BIM) has been steadily increasing in the building industry. This increase has led many project teams to assess design and constructability for projects in a 3D, BIM-based, environment. Despite this increased use, many projects still use traditional 2D documentation to communicate design concepts to various project participants. Mixed Reality (MR) can technically be used to visualize 3D design content without the need for 2D paper communication, but in practice it is not clear how users would feel about replacing traditional 2D drawings with 3D MR models. This research investigates the perceptions of industry professionals about replacing paper construction documents with a 3D MR based model. To evaluate behavioral and ideological patterns and changes, 18 electrical construction industry practitioners built two different conduit models using the same prefabricated pieces. In one iteration, they were provided with design communication through a MR visualization interface. In the other iteration, they used traditional paper plans. A pre-activity questionnaire was given to capture their ideas about a new technology being introduced and a post-activity questionnaire helped to evaluate their thoughts after using MR to build the conduit. During the conduit assembly activity, participants were video and audio recorded to capture any verbal comments related to their perception of the activity. Participants showed a wide array of reactions to the technology. Although participants unanimously reported that MR was easier to use than paper plans, some voiced other concerns. For example, some participants considered to only be effective as an educational tool. Some participants suggested it could supplement, but not replace, existing paper plans, while others thought it could indeed be used as the primary design communication method. Future research will study the relationship between perception and performance of the participants in this session.