The transparency of PC material is not as good as PMMA material. Transparent prototype usually adopt PC and PMMA material,to form definite shape by the use of CNC processing,and then grinding with sandpaper to smooth,and adopt cotton which coat polishing compound ,polishing to transparent.
It would take a long time,so the cost is also high.Also can use the method of silicon copy mould,copy out the transparent PU.But the transparency is not as good as CNC processing.