Author 
Comment/Response 
Juan Herrera

11/25/09 8:37pm
I'm trying to plot electric field lines as tubes with a parametric plot. I build a list with n points as
pts = BuildPointList[pa_,pb_,v_]
so that pts[[1]] is the list of points, and pts[[2]], pts[[3]] are lists giving two vectors perpendicular to the field line at each point. I go on to define
F[p_,i_,t_]:=p[[1, i]] + p[[2, i]] Cos[t] + p[[3, i]] Sin[t]
When I plot with
ParametricPlot3D[
F[pts, i, t],
{i, 1, n , 1},
{t, 0, 2π}]
I obtain a field line as a tube. But when I try plotting two lines as
ParametricPlot3D[
{F[pts1, i, t],
F[pts2,i,t]},
{i, 1, n, 1},
{t, 0, 2π}]
I get
ParametricPlot3D::ppfun: Argument {F[pts1, i, t], F[pts2, i, t]} is not a list with three or four elements.
What's wrong here? Thanks
Juan 〚
URL: , 
