Thank you Bryn and Ivo. I agree binary format is more efficient. But I am reluctant to do that because of the issue of portability. I may run the code on both Linux clusters and IBM machines. My earlier experience shows me that the binary files on the two system are not compatible, i.e., I cannot load the data generated on a IBM machine on a Linux system. Does the little/big endian parameter solve this problem in paraview? Thanks.
Shi ----- Original Message ---- > From: Bryn Lloyd <[EMAIL PROTECTED]> > To: Ivo Roghair <[EMAIL PROTECTED]> > Cc: Shi Jin <[EMAIL PROTECTED]>; paraview@paraview.org > Sent: Friday, November 28, 2008 12:17:39 AM > Subject: Re: [Paraview] File Format for Particles > > Hi Shi, > > Yes, for large amounts of data you should use the binary (not ascii) formats. > It > is very simple to switch between ascii/binary. In the writer classes (e.g. > vtkPolyDataWriter) you can usually call the function SetFileTypeToBinary() or > SetFileTypeToASCII(). > > > An unstructured grid can of course be used to visualize your data in > paraview. > Since you not have cells (tetrahedra, hexahedra, etc.) a vtkPolyData data > structure and associated file type might be better, since it uses slightly > less > storage and if you add the points as "Verts" Paraview will automatically > display > them using glyphs (sphere,arrow,..) > > File formats are described here: > http://www.vtk.org/pdf/file-formats.pdf > > > --Bryn > > > > > > Ivo Roghair wrote: > > Hi Shi, > > > > Saving such amounts of data in ascii format is not going to be efficient. > > We > just accepted this fact, otherwise we should go to binary formats. > > > > In our group we have discrete particle simulations, and we export vtk files > (xml format -- an unstructured grid to be precise) that contains all the > particle data. I have included an example of such a file below. You write the > point positions of the particles first, followed by data concerning the > movement > of the particle, the diameter and other stuff like rotation, temperature, > etc... > I don't see what you mean by redundant data. When you load this file into > Paraview choose the glyph option, choose 'sphere', set 'radius' to 1 (it is > initially set to 0.5), scale mode to 'scalar' and scale factor to 1. You can > then draw the particles. You can color them by velocity, temperature, > rotation > or whatever you included in the file, or you can choose to show arrows > (another > glyph) to display the particle movement. > > For the flow field, which is calculated on a structured grid, you can use > another file format, e.g. rectilinear grid. In all cases the kitware/vtk file > formats documentation is going to be useful. > > > > Regards, > > Ivo Roghair > > > > PhD student at Fundamentals of Chemical Reaction Engineering > > University of Twente, The Netherlands > > > > ------------------ BEGIN EXAMPLE FILE --------------------- > > > > > > > > > > > format="ascii"> > > 0 0 0 1 1 1 0 0 1 > > > > > > > > > format="ascii"> > > 4 4 4 4 0 0 2 2 -2 > > > > > > 0.1 0.5 1 > > > > > > 273 300 350 > > > > > > > > > > > > > > > > > > > > > > > > > > > > ---------- END EXAMPLE FILE -------------- > > > > Shi Jin wrote: > >> Hi there, > >> > >> I am doing a simulation of fluid-particle interactions, in which I > >> generate a > lot of data for particles. I am looking for the efficient file format to > store > my particle information for visualization with paraview. For example, is > there a > file format that allows me to store all the particle information at a given > time > in a single ascii file, which looks like > >> #1-id 2-radius 3-rho_p 4-fixed 5-x 6-y 7-z 8-u 9-v 10-z 11-w1 12-w2 13-w3 > 14-alpha 15-theta 17-phi > >> 0 0.500000 1.200000 0 2.077176 2.678227 8.649375 0.000000 0.000000 > >> 0.000000 > 0.000000 0.000000 0.000000 0.000000 0.000000 > >> 1 0.500000 0.800 0 2.728281 0.873571 6.806029 0.000000 0.000000 0.000000 > 0.000000 0.000000 0.000000 0.000000 0.000000 > >> ... > >> > >> I guess for the purpuse of visualization, we need radius, rho_p(for > >> color), > x,y and z at least. The rotation information would be nice to have but is > considered optional at this stage. > >> I am thinking to save different time results in different files to make > >> the > loading efficient in terms of memory since I have a lot of particles here. > Then > we can produce animation using time control. I guess we could use VTK formats > but that has lots of redundant information. > >> > >> I saw some very early discussion on a similar topic in the forum but > >> didn't > get the conclusive answer. I would appreciate some advice for the current > version of paraview. > >> > >> Thank you very much. > >> > >> -- > >> Shi Jin, PhD > >> > >> > >> > >> _______________________________________________ > >> ParaView mailing list > >> ParaView@paraview.org > >> http://www.paraview.org/mailman/listinfo/paraview > >> > > > > _______________________________________________ > > ParaView mailing list > > ParaView@paraview.org > > http://www.paraview.org/mailman/listinfo/paraview > > > > > -- ------------------------------------------------- > Bryn Lloyd > Computer Vision Laboratory > ETH Zürich, Sternwartstrasse 7 > CH - 8092 Zürich, Switzerland > Tel: +41 44 63 27690 > Fax: +41 44 63 21199 > ------------------------------------------------- _______________________________________________ ParaView mailing list ParaView@paraview.org http://www.paraview.org/mailman/listinfo/paraview