The design process usually starts with rough doodles and sketches to create a basic visual representation of the solution to a problem. The processes from this conceptual stage to more detailed specifications has often been segmented between incompatible physical and virtual representations. This work explores digital 3D sketching using large touch panel displays and active pen technology for the use in the early stages of the design process. We focus on rendering high quality 3D curves in a free-form sketching environment. There are two major challenges we provide approaches for; transforming our low resolution input data to a resolution independent format, and rendering dense curve representations at high quality in real time.