Plot3d File Format for Grid and Solution Files

This page describes the Plot3d file format for writing CFD structured grids and solutions. Below are examples for reading the files using Fortran 77 code. The examples assumes the grid file has been opened to unit 7 and the solution file to unit 8. Shown are examples for 2D, formatted, single-block files and 3D, unformatted, multi-block files. Permutations of these formats are possible and should be evident from the examples.

2D, Whole, Formatted, Single-Block Grid and Solution

      parameter ( imax = 100 )
      parameter ( jmax = 100 )

      integer i
      integer j
      integer m
      integer n
      integer ni
      integer nj
 
      real mach   ! freestream Mach number
      real alpha  ! freestream angle-of-attack
      real reyn   ! freestream Reynolds number
      real time   ! time

      real x(imax,jmax)
      real y(imax,jmax)

      real q(imax,jmax,4)

      open ( unit=7, form='formatted', file='2D.x' )
      open ( unit=8, form='formatted', file='2D.q' )

      read(7,*) ni, nj
      read(7,*) 
     &    (( x(i,j), i=1,ni), j=1,nj),
     &    (( y(i,j), i=1,ni), j=1,nj)

      read(8,*) ni, nj
      read(8,*) mach, alpha, reyn, time
      read(8,*) ((( q(i,j,n), i=1,ni), j=1,nj), n=1,4)

3D, Whole, Unformatted, Multi-Block Grid and Solution

      parameter ( imax  = 100 )
      parameter ( jmax  = 100 )
      parameter ( kmax  = 100 )
      parameter ( nbmax =  10 )

      integer i
      integer j
      integer m
      integer n
      integer nblocks
      integer ni (nbmax)
      integer nj (nbmax)
      integer nk (nbmax)
 
      real mach   ! freestream Mach number
      real alpha  ! freestream angle-of-attack
      real reyn   ! freestream Reynolds number
      real time   ! time

      real x(imax,jmax,kmax,nbmax)
      real y(imax,jmax,kmax,nbmax)
      real z(imax,jmax,kmax,nbmax)

      real q(imax,jmax,kmax,nbmax,5)

      open ( unit=7, form='unformatted', file='3D.x' )
      open ( unit=8, form='unformatted', file='3D.q' )

      read(7) nblocks
      read(7) ( ni(m), nj(m), nk(m), m = 1, nblocks )
      do  m = 1, nblocks
        read(7) 
     &    ((( x(i,j,k,m), i=1,ni(m)), j=1,nj(m)), k=1,nk(m)),
     &    ((( y(i,j,k,m), i=1,ni(m)), j=1,nj(m)), k=1,nk(m)),
     &    ((( z(i,j,k,m), i=1,ni(m)), j=1,nj(m)), k=1,nk(m))
      enddo

      read(8) nblocks
      read(8) ( ni(m), nj(m), nk(m), m = 1, nblocks )
      do  m = 1, nblocks
        read(8) mach, alpha, reyn, time
        read(8) 
     &    (((( q(i,j,k,m,n), i=1,ni(m)), j=1,nj(m)), k=1,nk(m)), n=1,5)
      enddo