Hi Ramesh-
If I am reading the documentation correctly, you create the PTF file using elcap, which ships in the Olympus tree -- look in its bin directory. I'm not clear if you really do mean "ITC" (never heard of it) or "ICT", which is a supported input type. Here's an example from the Olympus User Manual:
This elcap example reads in the 65nm.ict file and creates the 65nm.ptf file. The PTF will
include the capacitance generation information. It also generates gnuplot files for each
pattern and configures the gnuplot files to use spacing as the x-axis and have total,
lateral and ground cap values plotted. The gnuplot application uses the generated
gnuplot_ICT_jpeg.cmds file to create the necessary JPEG files needed to display all the
plots.
elcap -inFile 65nm.ict -gnuplotFiles -gnuplotXaxis spacing -resType all -fileType jpeg gnuplot gnuplot_ICT_jpeg.cmds
There's a few dozen different options depending on what you want to keep out of the file (or add to it), and also switches for running it on a grid system so it finishes faster. You can find the User's Manual either from the GUI or at <your_install_path>/sierra/doc/docs/olympus_user.pdf .