Define a new family using the Metric Generic Model face based family template.

C:\ProgramData\Autodesk\RVT 2015\Family Templates\English Imperial\Generic Model face based.rft

Save it as a new custom family

C:\ProgramData\Autodesk\RVT 2015\Libraries\PS\Doors\Fittings\ dh1.rfa

Define a Door Handle Family 01

Assign the correct Family category and parameters. To do this click on <Modify><Properties><Family Categories and Parameters>

Define a Door Handle Family 02

Select <Doors> and accept the default parameters and click <OK>

Define a Door Handle Family 03

This allows us to assign the components we create in this family to the sub-categories of the door family.
Create an extrusion as follows (viewed from the <Ref. Level> Floor Plan)

Define a Door Handle Family 04

Viewed from the Front Elevation:

Define a Door Handle Family 05

Create the following reference lines on the <Center (Front/Back)> plane.

Define a Door Handle Family 06

Viewed in 3D

Define a Door Handle Family 07

Sweep a circular profile along the path defined by the reference lines.

Define a Door Handle Family 08

Define a Door Handle Family 09

Set the sub-categories of the components created appropriately.

Define a Door Handle Family 10

Chances are this handle will not be made of the same material as the panel it is hosted on, so create a material type parameter for the family. I assigned a polished stainless steel material to this parameter.

Define a Door Handle Family 11

Assign the material parameter to the handle shapes.

Define a Door Handle Family 12

Save the file.