[Paraview] writing a bunch of polyhedrons

[Tomislav Maric]

Hi everyone, 

I have a list of polyhedrons which have arbitrary shape, and I would like to write them all down 
into a single .vtk file. I am using the POLYDATA data set. Right now, my option is:

init global points
init global faces

for all polyhedra:
    get local points
    get local faces
    add local points to global points
    map+add local faces to global faces

open the file for writing
write the .vtk header for POLYDATA 

for all points:
    write the points

for all faces:
    write the polygons

Is it possible to make this more effective? Right now I am duplicating my information when copying/mapping
to global lists. If I want to write into this file without copying the polyhedron data, I will still need
a memory buffer to store the file from the insertion point on, and it would be needed twice for each 
polyhedron:

file::seek up

write the points

file::seek down

write the faces

and at the end, I would need to insert the 

POINTS nPoints dataType

and 

POLYGONS n size

at apropriate places. 

Any advice would be appreciated! :)

Thanks!