Re: Draw a circle in 3D

*To*: mathgroup at smc.vnet.net*Subject*: [mg99603] Re: [mg99593] Draw a circle in 3D*From*: "David Park" <djmpark at comcast.net>*Date*: Sat, 9 May 2009 03:19:43 -0400 (EDT)*References*: <31268562.1241757022354.JavaMail.root@n11>

The Presentations package at my website ($50), among many other things, has a Circle3D, and also Disk3D, routine. Circle3D[position, normal, radius, anglerange] will draw a circle with the specified position and radius. The orientation of the circle is given by the normal vector. Here is an example of its use, drawing two circles at different locations with different colors and orientations, and also adding arrows at the center to show the normals. Draw3DItems[ {Opacity[0.8], Lighter@Brown, Circle3D[{0, 0, 0}, {0, 0, 1}, 2, Mesh -> {5, 10}], Pink, Circle3D[{2, 2, 2}, {2, 0, 2}, 1, Mesh -> None], Green, Arrow3D[{0, 0, 0}, {0, 0, 1}, {0.3}], Arrow3D[{2, 2, 2}, {2, 2, 2} + Normalize[{2, 0, 2}], {0.3}]}, NeutralLighting[0, 0.5, 0.1], PlotRange -> All, Axes -> True, ImageSize -> 400] One method to obtain the circles without the package would be to parametrize a 3D circle that lies in the xy-plane at the origin and then use Rotate[g, {u, v}] to orient it in the desired direction. (And also use Translate if you want it at some other location.) David Park djmpark at comcast.net http://home.comcast.net/~djmpark/ From: ibmichuco at hotmail.com [mailto:ibmichuco at hotmail.com] Hi, I would like to draw circles of radius 1 centered at the origin in 3d, similar to (but not limited to) the longitude lines of the globe. That is planes that lies in the a particular plane made an angle with the one of the axes etc. Is there any mathematica function to do this? Many thanks in advance, Michuco