RE: draw vertical cylinder with no surface lines

*To*: mathgroup at smc.vnet.net*Subject*: [mg71626] RE: [mg71588] draw vertical cylinder with no surface lines*From*: "David Park" <djmp at earthlink.net>*Date*: Sat, 25 Nov 2006 05:37:06 -0500 (EST)

Murray, You use EdgeForm[] to eliminate (or control) the edge lines on the rectangular faces of a surface. Eliminating the edges still sometimes leaves a trace of the edges where the lighting plane changes. An alternative is to draw the edge lines but use a color that is just a little darker than the surface. That subdues the edges. The following draws without the edges. I used the NeutralLighting options in DrawGraphics so the surface colors would show properly. Honeydew is probably too light a color to use and the colors you obtained were from the lights. There is a glitch in the SurfaceColor command in that if you use the multi-argument form, SurfaceColor[Honeydew, Honeydew, 2], and then subsequently use the single argument form for another surface the other arguments are still in affect. Drawing lines on the vertical sides of the can depends, of course, on the viewpoint. I did it by trial and error. Here is the plot. Needs["DrawGraphics`DrawingMaster`"] SetOptions[Arrow3D, HeadScaling3D -> 1, HeadLength3D -> 0.25, HeadWidth3D -> 0.55]; Module[ {\[Theta]1 = 0.25, \[Theta]2 = -0.3}, Draw3DItems[ {(* Draw the side surface *) SurfaceColor[Salmon], EdgeForm[], ParametricDraw3D[{Cos[\[Phi]], Sin[\[Phi]], z}, {\[Phi], 0, 2 \[Pi]}, {z, 0, 2}, PlotPoints -> {51, 2}], (* Draw the top surface *) SurfaceColor[LightSteelBlue], CylindricalDraw3D[2, {r, 0, 1}, {\[Phi], 0, 2 \[Pi]}, PlotPoints -> {2, 51}], (* Draw outline *) ParametricDraw3D[{Cos[\[Phi]], Sin[\[Phi]], 0}, {\[Phi], 0, 2\[Pi]}, PlotPoints -> 51], ParametricDraw3D[{Cos[\[Phi]], Sin[\[Phi]], 2}, {\[Phi], 0, 2\[Pi]}, PlotPoints -> 51], ParametricDraw3D[{Cos[\[Theta]1], Sin[\[Theta]1], z}, {z, 0, 2}, PlotPoints -> 2], ParametricDraw3D[{Cos[\[Theta]1 + \[Pi]], Sin[\[Theta]1 + \[Pi]], z}, {z, 0, 2}, PlotPoints -> 2], (* Draw and label the arrows *) Thickness[0.01], Cobalt, SurfaceColor[PrussianBlue], Arrow3D[{0, 0, 2}, {Cos[\[Theta]2], Sin[\[Theta]2], 2}], Arrow3D[{Cos[\[Theta]2], Sin[\[Theta]2], 0}, {Cos[\[Theta]2], Sin[\[Theta]2], 2}], Black, Text["r", {1/2Cos[\[Theta]2], 1/2Sin[\[Theta]2], 2}, {-1, -1}], Text["h", {Cos[\[Theta]2], Sin[\[Theta]2], 1}, {2, 0}]}, NeutralLighting[0.3, 0.5, 0.1], TextStyle -> {FontSize -> 12, FontWeight -> "Bold", FontFamily -> "Courier"}, Boxed -> False, Background -> Linen, ImageSize -> 300] ]; David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Murray Eisenberg [mailto:murray at math.umass.edu] For an illustration, I want to draw a closed cylindrical "can" -- a cylinder with its axis vertical -- along with arrows (with labels) indicating radius and height. The ways I've found, either using Graphics`Shapes`Cylinder or ParametricPlot3D, insist on drawing curves on the vertical wall of the cylinder and, if I use ParametricPlot3D to draw the top, too, on the top. Is there some way to suppress these curves? Of course I still need the circles bounding the top and bottom to be drawn as well as two vertical lines that demarcate the wall of the cylinder from the ambient space. I just want to rely upon lighting and shading to suggest the three-dimensionality. Here's my effort so far using DrawGraphics: SetOptions[Arrow3D,HeadScaling3D->1,HeadLength3D->0.25, HeadWidth3D->0.55]; Draw3DItems[{ SurfaceColor[Honeydew,Honeydew,2], ParametricDraw3D[{Cos[\[Phi]],Sin[\[Phi]],z},{\[Phi],0,2Pi},{z,0,2}, PlotPoints->{51,2}], SurfaceColor[Honeydew,Honeydew], CylindricalDraw3D[2,{r,0,1},{\[Phi],0,2Pi},PlotPoints->{2,51}], Thickness[0.02],Cobalt,SurfaceColor[PrussianBlue], Arrow3D[{0,0,2},{0.9165,-0.4,2}] }, Boxed->False]; -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305