aUCBLogo Demos and Tests / nmr_praezession

to NMR_Praezession
   perspective
   enableCylinderLines
   disableRoundLineEnds
   setPS [5 5]
   schwarz=RGB 0 0 0
   setPC schwarz
   axes 250
   setPS [7 7]
   blau=RGB 0 0 1
   setPC blau
   Pfeil 200
   pu fd 200 rt 90 Label [B]
   rt 45 fd 2*first labelsize [B] lt 45 label [0]
   home
   rot=RGB 1 0 0
   setPC rot
   size=150
   angle=30
   PU fd size
   PD down 90 circle size*tan angle  up 90
   PU back size
   l=size*Sqrt (1+Sqr Tan angle)
   rt angle PD Pfeil l PU
   fd l seth 90 label [M]
   Home
   hT
   rotatescene
end

to axes size
   pd
   home
   setLabelAlign 1 1
   setposxyz [1 0 0]*size   seth 90   label "x   home
   setposxyz [0 1 0]*size   seth 90   label "z   home
   setposxyz [0 0 -1]*size   seth 90   label "y   home
   circle 0.03*size
end

to Pfeil l
   lSpitze=l/8
   rSpitze=l/20
   p=PosXYZ
   ori=Orientation
   PD fd l-lSpitze/2
   PU back lSpitze/2 rt 90 fd rSpitze
   SurfaceStart
   back rSpitze
   dphi=10
   for [r 1 0 -.1]
   [   for [phi 0 360 dphi]
      [   down dphi
         PD fd r*rSpitze
         PU back r*rSpitze
      ]
      lt 90   fd lSpitze/9 rt 90
      SurfaceColumn
   ]
   SurfaceEnd
   setPosXYZ p
   setOrientation ori
end