Using Virtual Reality and Rapid Prototyping to co-create together with hospitalized children. Vanessa Ghiraldeli Usó 1 , Frode Eika Sandnes 2 , Fausto Orsi Medola 1,3 1 Department of Design, School of Architecture, Arts and Communication, Sao Paulo State University – UNESP, Av Eng Luiz Edmundo Carrijo Coube, nº 14-01, Bauru, 17033-360, Brazil. 2 Department of Computer Sciences, Faculty of Technology, Arts and Design, Oslo Metro- politan University, Pilestredet 35, 0166 Oslo, Norway. 3 Programme of Post-graduation in Design, School of Architecture, Arts and Communicati- on, Sao Paulo State University – UNESP, Av Eng Luiz Edmundo Carrijo Coube, nº 14-01, Bauru, 17033-360, Brazil. Abstract. This study reports on a social project involving a collaborative pro- cess to co-create toys together with hospitalized children, using Virtual Reality, play practices and 3D Printing technologies. The project had two main phases: the co-creative process with the children and the production of prototypes based on the children’s creative drawings. For the activities involving the children, static virtual reality environments were created to stimulate the children to draw. These drawings were used as reference for the design of 3D toys that then were printed in plastic. A positive effect of the experience on the children’s be- haviour was observed during the hospital routine procedures. Despite the tech- nology required and considerably high cost for producing custom pieces with 3D printing, the project was executed successfully. This initiative shows the po- tential for practical interdisciplinary collaboration approaches between product design and health sciences. Keywords: Plaything · Virtual Reality · Hospitalized Child · Cancer · Rapid Prototyping. 1 Introduction Being hospitalized means to stay in an unfamiliar environment with unfamiliar people and to be subjected to routine therapeutic procedures that can be traumatic. Hospital- ized children are particularly vulnerable. Fear and anxiety, feelings that are commonly associate with hospitalization, can result in emotional distress leading to negative consequences such as sleep disturbances and separation anxiety [1]. Play is essential for the neuro psychomotor and social development of chil- dren. According to Francischinell et al. [2], therapeutic play refers to practices indi- This is a post-peer-review, pre-copyedit version of a chapter published in Advances in Additive Manufacturing, Modeling Systems and 3D Prototyping: Proceedings of the AHFE 2019 International Conference on Additive Manufacturing, Modeling Systems and 3D Prototyping, that is part of the Advances in Intelligent Systems and Computing book series (AISC, volume 975). The final authenticated version is available online at: https://dx.doi.org/10.1007/978-3-030-20216-3_26