The .ptd file extension is for text files used in the Piping Specification Database.
The specification database is a complicated spider web of interrelated text files that point to each other that define the allowable pipes, materials, fittings, insulation, and other objects.
Rather than create one from scratch, you're better off taking the existing database that comes with Creo and editing it - but be forewarned, it is a bit tedious. (Since they are text files, they can be edited in WordPad or NotePad.)
Thanks for the suggestion. Currently I am using the family for the fittings but it is getting tedious to call the valves in the piping assembly. If you suggest me how to add valve in the piping database as .pdt file it will be a great help for me.
Pl share if you have a tutorial file for the same.
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