@simonsig I think you mean ChemCraft? Which has been around since before 2004 and fairly well maintained, it also lets you create animated pictures of molecules, but it is limited in some features compared to 3DNA. One good thing about ChemCraft is that it is native in Linux as well, whereas 3DNA is only for Windows (correct me if i'm wrong?), although this is less of an issue nowadays thanks to virtual machine emulation.