Re: tubes program not working in version 9

*To*: mathgroup at smc.vnet.net*Subject*: [mg129013] Re: tubes program not working in version 9*From*: "Nasser M. Abbasi" <nma at 12000.org>*Date*: Sat, 8 Dec 2012 01:31:36 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-newout@smc.vnet.net*Delivered-to*: mathgroup-newsend@smc.vnet.net*References*: <k9s2rq$mp9$1@smc.vnet.net>*Reply-to*: nma at 12000.org

On 12/7/2012 12:37 AM, Roger Bagula wrote: > The problem seems to be sometimes it works but mostly it doesn't. > The tubes program was written for an earlier version > ( works in version 5 I think) by Mark McClure > and has worked fine for literally years. > I haven't got a clue what has gone wrong. > ( technically these are called channel surfaces or the like). > > TubePlotFrenet[curve_List, {var_, min_, max_}, radius_, opts___] := > Module[{tangent, unitTangent, normal, unitNormal, biNormal}, > tangent = D[curve, t]; > unitTangent = tangent/Sqrt[tangent.tangent]; > normal = D[unitTangent, t]; > unitNormal = normal/Sqrt[normal.normal]; > biNormal = Cross[unitTangent, unitNormal]; > ParametricPlot3D[ > curve + radius Cos[s] unitNormal + radius Sin[s] biNormal // > Evaluate, {var, min, max}, {s, 0, 2 \[Pi]}, opts]] > > r = Cos[q0*t] + 2; > x = r* Cos[p0*t]; > y = r *Sin[p0*t]; > z = Sin[q0*t]; > w0 = 8*{x, y, z} > h = TubePlotFrenet[w0, {t, 0, 2 \[Pi]}, 1, Axes -> None, > Boxed -> False, PlotPoints -> {64, 16}, > ColorFunction -> "CandyColors", MeshFunctions -> {#3 &}] > > My other tubes program which came from an answer in this group > still works. > Noticed few problems: tangent = D[curve, t]; when it should be tangent = D[curve, var]; after all, var is the independent variable symbol being passed and is the one build in. Also, there are no numerical values for the q0 and p0. When I wrote p0=1; q0=1; and fixed the above issue with var vs. t, then it worked. --Nasser