If I have a semi transparent object I can see objects behind it as long as I draw it later. I.e. I can see through it and the objects behind look lighter. If one of those objects is itself semitransparent it becomes invisible. Is this a bug or just a limitation in the rendering operation?

See https://github.com/openscad/openscad/issues/310 ----- Admin - PM me if you need anything, or if I've done something stupid... Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out! -- View this message in context: http://forum.openscad.org/Semi-transparent-object-behind-transparent-window-isn-t-visible-tp21930p22076.html Sent from the OpenSCAD mailing list archive at Nabble.com.

I don't think it is that issue. The rendering order isn't the problem. The problem is the alpha blend applied twice doesn't look any different from it applied once. On 16 August 2017 at 23:36, MichaelAtOz <oz.at.michael@gmail.com> wrote: > See https://github.com/openscad/openscad/issues/310 > > > > > ----- > Admin - PM me if you need anything, or if I've done something stupid... > > Unless specifically shown otherwise above, my contribution is in the > Public Domain; to the extent possible under law, I have waived all > copyright and related or neighbouring rights to this work. Obviously > inclusion of works of previous authors is not included in the above. > > The TPP is no simple “trade agreement.” Fight it! > http://www.ourfairdeal.org/ time is running out! > -- > View this message in context: http://forum.openscad.org/ > Semi-transparent-object-behind-transparent-window-isn- > t-visible-tp21930p22076.html > Sent from the OpenSCAD mailing list archive at Nabble.com. > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >

a. > I can see through it and the objects behind look lighter. If one of those objects is itself semitransparent it becomes invisible. b. > The problem is the alpha blend applied twice doesn't look any different from it applied once. Umm, perhaps a concrete example may help. ----- Admin - PM me if you need anything, or if I've done something stupid... Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above. The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out! -- View this message in context: http://forum.openscad.org/Semi-transparent-object-behind-transparent-window-isn-t-visible-tp21930p22118.html Sent from the OpenSCAD mailing list archive at Nabble.com.

I made a small example and found it only goes wrong if the transparency is created by the % operator. If it is made with the color module it works. sphere(10); translate([0, -20, 0]) %cube([10, 2, 10], center = true); translate([0, -50, 0]) color("white", 0.5) cube([20, 2, 20], center = true); If both transparencies are created with % then it works. So I think it is an order issue after all. It looks like the % operator trees are rendered later than the rest. That works if you don't have any other transparent objects but not if you have any made with color that are in front. ​ On 17 August 2017 at 22:44, MichaelAtOz <oz.at.michael@gmail.com> wrote: > a. > I can see through it and the objects behind look lighter. If one of > those objects is itself semitransparent it becomes invisible. > b. > The problem is the alpha blend applied twice doesn't look any > different > from it applied once. > > Umm, perhaps a concrete example may help. > > > > ----- > Admin - PM me if you need anything, or if I've done something stupid... > > Unless specifically shown otherwise above, my contribution is in the > Public Domain; to the extent possible under law, I have waived all > copyright and related or neighbouring rights to this work. Obviously > inclusion of works of previous authors is not included in the above. > > The TPP is no simple “trade agreement.” Fight it! > http://www.ourfairdeal.org/ time is running out! > -- > View this message in context: http://forum.openscad.org/ > Semi-transparent-object-behind-transparent-window-isn- > t-visible-tp21930p22118.html > Sent from the OpenSCAD mailing list archive at Nabble.com. > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org >