14_1_glr09_spacecurves.mw

> with(plots):
with(plottools):
 

Let's look at a position vector r(t): 

> r:=t->[8*cos(t),8*sin(t),t]:
 

This is a vector from the origin to the point r(t): at t=0 and t=Pi/3, 

> display3d(arrow([0,0,0],r(0),0.3,0.8,0.2,cylindrical_arrow,color=blue),arrow([0,0,0],r(Pi/3),0.3,0.8,0.2,cylindrical_arrow,color="Magenta"),axes=normal,view=[-9..9,-9..9,-9..9]);
 

Plot_2d
 

Let's put a point at the end of the vector, which lets us visualize the position without the vector: 

> display3d(sphere(r(0),0.5,color=blue,style=patchnogrid),sphere(r(Pi/3),0.5,color="Magenta",style=patchnogrid),axes=normal,view=[-9..9,-9..9,-9..9]);
 

Plot_2d
 

...and then we can see how the sphere moves with time... 

> nframes:=20:
curve2:=display([sphere(r(0),0.5,color=blue,style=patchnogrid),
seq(spacecurve(r(t),t=0..4*Pi*i/nframes,color=coral,thickness=3),
i=1..nframes)],insequence=true):
pt2:=display([seq(sphere(r(4*Pi*i/nframes),0.5,color=blue,style=patchnogrid),i=0..nframes)],insequence=true):
display({curve2,pt2},axes=normal,scaling=constrained,labels=[`x`,`y`,`z`],view=[-9..9,-9..9,-1..15]);
 

Plot_2d