Background : In the design field, collaboration is a key method that can widen the conceptual design horizon beyond an individual’s boundaries. Collaboration helps to share knowledge and develop ideas jointly in the design process. It also helps to communicate diverse viewpoints. The ADT model is a representational model for conceptual design. It is used to grasp artifacts as a communication medium between designers and users. During the observation process, three influential factors-physical, emotional, and cultural-are observed through diverse viewpoints. Methods : This paper discusses a method to enhance the design process by sharing observed information with team members who have diverse viewpoints and using the information to create novel ideas with these proposed support tools. It then evaluates the proposed tools empirically with ISDW participants. Moreover, the these proposed tools are considered based on the results of using at ISDW as a case study. Result : These two collaboration support tools, named “Category Camera” and the TTS method based on the extended ADT model are proposed in this research. Each process is visualized and shared by using “Category Camera” and the TTS method to share visual information such as idea sketches, notes, and photos. The experiment evaluating the proposed design process with “Category Camera” and the TTS method reveals that these tools help participants share and create opinions and ideas logically and beyond an individual’s boundaries. By using these tools, designers in a team can visualize their idea, share it with others, and create a novel design plan based on multicultural backgrounds. An example of the design process using “Category Camera” and the TTS method is provided in order to show the effectiveness of the proposed method. Conclusions : In this paper, a method to support the collaborative design process, using “Category Camera” and the TTS method, is developed based on the extended ADT model. “Category Camera” and the TTS method help designers understand users’ circumstances and needs by observing three factors-the physical factor, the Kansei (emotional) factor, and the cultural factor. Through these factors, a designer can determine users’ needs, including unconscious needs that are difficult to uncover using a survey questionnaire. An example in which “Category Camera” and the TTS method are used for collaboration among design teams is shown. With the proposed method, the designers were able to find a unique design solution that reflected multicultural values. While the efficiency of the method is clear, there are some additional considerations. First, the format of the worksheets used in the TTS method should be reconsidered. In the current study, sheets used for different steps have the same format. A more effective format for collaboration should be developed. Second, designers spent too much time on the first and second steps of the TTS method. In order to simplify use, procedures that took a long time should be modified by introducing the use of electronic technologies.