Byron Dom
2020-Jul-19 23:10 UTC
[R] rgl terminology: the definitions of "thickness" and "width" in rgl
I'm struggling to come up to speed with rgl. At the moment, I'm struggling with the function arrows3d(). In the R documentation for that, two parameters/arguments are mentioned:?"thickness" (of the arrow's shaft) and "width"?(of the arrow's shaft).? Naively, I would expect the arrow's shaft under normal circumstances to be cylindrical and its width or thickness would reduce to the single parameter "diameter." Then in some cases like plotting a 2-dimensional arrow on a 2-dimensional surface embedded?in a 3D space, things like "width" would have an obvious meaning. Would someone explain this to me, including the difference between width and thickness. Thanks in advance. [[alternative HTML version deleted]]
Jim Lemon
2020-Jul-21 09:00 UTC
[R] rgl terminology: the definitions of "thickness" and "width" in rgl
Hi Byron, As in the help page, three types of arrows can be specified. In the "rotation" type, "width" is the parameter that determines the diameter of the cylindrical shaft as a fraction of the "barb", the cone at the end. In the default "extrusion" arrow, "thickness" is the fraction of the "width" of the shaft. Effectively how thick the fettuccine is relative to its width. Thickness doesn't seem to affect the "lines" or "flat" type, with the latter apparently of zero thickness. Jim On Tue, Jul 21, 2020 at 11:39 AM Byron Dom via R-help <r-help at r-project.org> wrote:> > I'm struggling to come up to speed with rgl. At the moment, I'm struggling with the function arrows3d(). In the R documentation for that, two parameters/arguments are mentioned: "thickness" (of the arrow's shaft) and "width" (of the arrow's shaft). > Naively, I would expect the arrow's shaft under normal circumstances to be cylindrical and its width or thickness would reduce to the single parameter "diameter." Then in some cases like plotting a 2-dimensional arrow on a 2-dimensional surface embedded in a 3D space, things like "width" would have an obvious meaning. > Would someone explain this to me, including the difference between width and thickness. > Thanks in advance. > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code.
Duncan Murdoch
2020-Jul-21 15:32 UTC
[R] rgl terminology: the definitions of "thickness" and "width" in rgl
On 21/07/2020 5:00 a.m., Jim Lemon wrote:> Hi Byron, > As in the help page, three types of arrows can be specified.Actually four types: rotation, extrusion, lines, flat. But the rest of your answer is right. Duncan Murdoch In the> "rotation" type, "width" is the parameter that determines the diameter > of the cylindrical shaft as a fraction of the "barb", the cone at the > end. In the default "extrusion" arrow, "thickness" is the fraction of > the "width" of the shaft. Effectively how thick the fettuccine is > relative to its width. Thickness doesn't seem to affect the "lines" or > "flat" type, with the latter apparently of zero thickness. > > Jim > > On Tue, Jul 21, 2020 at 11:39 AM Byron Dom via R-help > <r-help at r-project.org> wrote: >> >> I'm struggling to come up to speed with rgl. At the moment, I'm struggling with the function arrows3d(). In the R documentation for that, two parameters/arguments are mentioned: "thickness" (of the arrow's shaft) and "width" (of the arrow's shaft). >> Naively, I would expect the arrow's shaft under normal circumstances to be cylindrical and its width or thickness would reduce to the single parameter "diameter." Then in some cases like plotting a 2-dimensional arrow on a 2-dimensional surface embedded in a 3D space, things like "width" would have an obvious meaning. >> Would someone explain this to me, including the difference between width and thickness. >> Thanks in advance. >> >> [[alternative HTML version deleted]] >> >> ______________________________________________ >> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. >