This is a customizer for creating arc shaped cabinet handles or drawer handles.There are two basic styles that can be created: cylindrical and spheroidal.
The design is 3D-printer friendly: no supports are needed except for spheroidal handles with really large X and Y dimensions (length and clearance) and a really short Z dimension (height).
All dimension parameters, except for the tolerance parameters, are shown in the second picture. The customizer can optionally create nut holes for inserting nuts into the handle for the screws to screw into. The nut holes are visible in the vertical yellow handle in the first picture. The customizer can create plugs for the nut holes in case you are mounting them vertically and want to hide the holes.
It can also create a smaller test piece so that you can test the sizing of the holes to make sure that the holes will be sized well for the screws and nuts.
The funky looking green handle second from the bottom wasn't directly created by the customizer; it's just a merged model of the handle above it and the handle below it.
The customizer will create 1) the handle, 2) the test piece, or 3) the nut hole plugs. To simplify viewing of this thing, the third STL has all three of these options combined into a single STL file.
Update 2019-11-22: Version 2
There is now support for a back-plate, such as in the red, cyan, magenta, teal, and steel blue handles.
In addition to the handles shaped like a cylindrical section, the customizer can also create handles shaped like a spheroidal section, such as the orange, white, and gold handles. The height/clearance ratio determines whether or not the spheroid is oblate or prolate. If the ratio is less than 1 it's oblate like the orange handle, if it's greater than 1 it's prolate like the gold handle, and if it's equal to 1 it's a sphere like the white handle. The actual height will be the specified height plus the length of the fillet radius.
There is a now a parameter for the number of screw holes, which can be 1 or 2. If 1 is selected, then it will be centered on the handle and the parameter for distance between screw holes will be ignored.