Spatial augmented reality (SAR) promises the integration of digital information in the real (physical) world through projection. In this doctoral symposium paper, I propose different tools to fasten and ease the drawing by projecting photos, virtual construction lines and interactive 3D scenes. After describing them, I explain some future challenges to explore such as the creation of tools which helps to create drawings that are "difficult" to achieve for a human being, but easy to do by a computer. Furthermore, I propose some insights for the creation of digital games and programs which can take full advantages to have a human and physical constraints.