Yes this is something I do as well...I also have parameters for $fn so that smooth objects can be chunky as fast. Adding parameter for printable vs display helps too allowing me to place parts into relationships with others to see how they will fit together once printed. All that takes time of course when you just want to knock out a quick part so I don't always do it...then I regret it when the quick part becomes complex. I just wish rendering parts was faster...I don't quite get WHY is is so slow on SCAD compared to other programs but I accept that it is and I do not want to give up SCAD so I will make my computer choice to match the application....and continue to find ways to optimize my designs. -- Sent from: http://forum.openscad.org/