Parapet Design
Hi, The term you need to use is "mouldings" or "millwork". There are many resources on these shapes. "Shaping" is the manufacturing process in producing these and is related to routing and others in the millwork arena.
Go to here or here or here to view catalogs of millwork shapes. You will find that these are broken down into categories by application (eg. Crowns are crown mouldings).
PVC manufacturing of mouldings has a growing share of market but the process is not conventional millwork but instead extruding and sometimes casting. Nomenclature or names used for the products should remain similar for the pvc and wood product industries.
The specific dimensions of every shape are not as easy to find so I typical reference a dimension that is give, then I copy/paste a screen grab into ACAD and I scale or align the target points on the pasted image to a line of the true dimension in ACAD. I then have a true sized image of the profile to generate lines, arcs, or splines upon.
Realize that the lengths and radii of the geometry should folllow a little convention, whether in metric or Imperial/English. You shouldn't end up with crazy dimensions in either system. Sixteens or thirty-seconds of an inch should be prominent in Imperial/English (occasionally a sixty-fourth).
Even your image in the initial posting can serve this process if you have at least one known dimension and you maintain the aspect ratio of the original image file.
Good luck!
Blaine Young
Senior Engineering Technician, US Army
Mr Blyoung,
Thank for reply,
i think Moulding or millwork is for interior. please see attachment, The design is similar to that but this is i think different thing. 
