[pstricks] direction of vector valued function

[Herbert Voss]

Hamed Al-Sulami schrieb:
> Is there a way to draw an arrows on the graph of vector valued function
> 
> To indicate the curves orientation batter than the one of doing in the
> following example.

http://melusine.eu.org/syracuse/pstricks/pst-solides3d/bonus/addons_pst_solides/?page=13

there are some examples for drawing normal vectors. You can modify it
to draw direction verctors instead.

Herbert