@mirjman said: here's a very easy way to do this: draw a stray line anywhere select your component and the line at the same time use "flip along" to mirror on world axis delete stray is this what you are asking I don't think so, mirjman, as that sounds like a simply a flipped, but not a mirroredobject, but adding the extra steps as described by Wo3Dan, i.e. making the original object and your "stray line" a new group, which will have its bounding box aligned to the axes, then using scale -1 worked just fine. Thanks! John

Well, my approach would not have been too different from Jean's - what I meant was to draw the whole dome first and then use the Follow me tool to extrude a rib along one of the radial lines of the dome. THEN make the radial array. He just made it in a different order (and the "rib" was created differently). Ribbed dome.skp