SRF2CAD Version 1.2

Author: William M. Chan

Description:

This tool is used to project structured surface grids in PLOT3D format to native CAD geometry via the CAPRI interface.

Two modes of projection are allowed: inverse evaluation and forward evaluation. The inverse evaluation mode provides smoother results, is slower than the forward mode and does not require uv values to proceed. The forward evaluation mode performs the interpolation in parameter space using uv values and may not give smooth results in physical space in high curvature regions. In general, the inverse evaluation mode is recommended.

   Input files

    - structured surface grids (PLOT3D multiple grid unformatted)

    - CAD tag file generated by surgrd. The filename is assumed
      to be of the form surgrd.partname.modelername.tag

      where partname = CAD part name that the tags are referring to
                       (no extensions)
            modelername = 3 letter code for CAD modeler

                          cat - Catia
                          cv5 - CatiaV5
                          fls - FELISA
                          ide - I-DEAS
                          opc - OpenCASCADE
                          prs - Parasolid
                          pro - Pro-Engineer
                          slw - SolidWorks
                          uni - Unigraphics

      The partname and modelername are used to identify the CAD part
      and modeler for interfacing with CAPRI.

   Output file

    - projected structured surface grids where grid points lie on
      native CAD geometry (PLOT3D multiple grid unformatted)

CAD Tag File Format:

The tag file can be formatted or unformatted and can be read with the following Fortran 90 statements.
     read(iu) ngrid
     read(iu) (nj(n),nk(n),n=1,ngrid)
     do n=1,ngrid
        is = ngp(n)
        ie = is + nj(n)*nk(n) - 1
        read(iu) (vtag(i),i=is,ie),(ftag(i),i=is,ie), &
                 (cu(i),i=is,ie),(cv(i),i=is,ie)
     enddo

     Let the total number of grid points over all grids be ntot.
     Define arrays vtag, ftag, cu, cv of size ntot. The cu and cv
     arrays must be present in the file but their values are only
     meaningful in forward evaluation mode.

     ngrid = number of grids in input surface grid file
     nj(n),nk(n) = j and k dimensions of grid n
     ngp(n)      = starting index of nth grid information in arrays
                   vtag, ftag, cu, cv
                 = (sum from i=1 to i=n-1 of nj(i)*nk(i)) + 1
                 = 1 + total number of grid points up to grid (n-1)
     vtag(i)     = volume tag for ith point
     ftag(i)     = face tag for ith point
     cu(i)       = u value for ith point (only used in forward evaluation mode)
     cv(i)       = v value for ith point (only used in forward evaluation mode)

Usage:

  srf2cad [input surface grid filename] [tags filename] \
          [output surface grid filname] -uv

  - must contain at least the first three fields
  - use optional field -uv to indicate uv forward evaluation mode
    (default is inverse evaluation mode)

    e.g., srf2cad plot3d.sur surgrd.test.pro.tag grid.sur -uv

  srf2cad -help  (to get usage)

Software access:

The srf2cad software module requires the CAPRI libraries which is a commercial product by CADNexus. An executable for srf2cad can be requested from CADNexus directly.
Last modified: Thu July 06 17:25:00 2006