Its value does have some considerations. It needs to be small enough to not be visible but large enough to not allow z-fighting when zoomed out a reasonable distance. I also make sure it is representable exactly in floating point, so I use 1/128. On Thu, 23 Apr 2020 at 14:51, Troberg <troberg.anders@gmail.com> wrote: > I call it itsy (as it itsy bitsy). Any small number where the precise value > isn't of importance. > > > Max Bond wrote > > Your approach is the conventional one. But we usually call the variable > > epsilon :) > > > > > > -- > Sent from: http://forum.openscad.org/ > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

Yes but only when the shared boundary can't be represented in floating point. Objects with exactly shared faces can be unioned by CGAL. On Thu, 23 Apr 2020 at 15:06, Kenneth R Sloan <kennethrsloan@gmail.com> wrote: > This is a general principle of computing : “any program such depends on (a > == b) is broken” > > Manufacturing has a similar concept : tolerance. > > I disagree with the claim that only “difference” needs a tolerance. It’s > also necessary when doing a “union” of two objects with a shared boundary. > > >> >> >> >> -- >> Sent from: http://forum.openscad.org/ >> >> _______________________________________________ >> OpenSCAD mailing list >> Discuss@lists.openscad.org >> http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >> > -- > -Kenneth Sloan > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

The common way to eliminate Z-fighting is switching to a logarithmic Z-buffer But i'm not sure if OpenCSG Require linear Z-buffer for boolean ops. Anyways i use the far faster and more robust 2d subsystem whenever possible. -- Sent from: http://forum.openscad.org/