(2019-10-24, 6:35)Philippe Hurbain Wrote: The simple solution is to use a ring3 and a ring4 (scaled 1x). For more complex cases there is the ring and cones calculator, in tools section of LDPE (see also http://www.philohome.com/isecalc/rings.htm for a stand alone version) . Technically (less vertices) it would be better to use chrd+ndis primitives+quads but it's more complex and not worth the trouble here.
Aha—two concentric rings. I think that did occur to me, but I wasn't sure if it would be "ethical" in LDraw. And they'll line up correctly, with no visible gap in between?
I do look forward to delving into LDPE and its tools, although I'm currently held up by my inability to launch the program (posted about here). I may try the standalone version, if I can get it to work under Wine, and if the situation arises again.