subroutine plotv(v,s,sp,etot,eplas,ecreep,t,m,nn,layer,mdi,
     * mshear,jpltcd)
c
c CONTACT: ap@marc.de
c      
c* * * * * *
c
c     define a variable for contour plotting
c
c     v            variable
c     s            stress array
c     sp           stresses in preferred direction
c     etot         total strain (generalized)
c     eplas        total plastic strain
c     ecreep       total creep strain
c     t            current temperature
c     m            element number
c     nn           integration point number
c     layer        layer number
c     mdi          number of direct stress components
c     mshear       number of shear stress components
c     jpltcd       absolute value of user defined plot code
c
c* * * * * *
      implicit real*8 (a-h,o-z)                                               dp
      dimension s(1),etot(1),eplas(1),ecreep(1),sp(1)
c
      dimension pv(3),r1(3,3)
c
      call princv(pv,r1,s,mdi,mshear,0,0,0,0)
      dmin=min(pv(1),pv(2),pv(3))
      dmax=max(pv(1),pv(2),pv(3))
c v = tresca equivalent stress
      if (jpltcd.eq.1) v=dmax-dmin
c
      return
      end