Can Expressions be used to Populate User Defined Properties... or other ideas

[dana.probert]

I am trying to crack the problem where a pipe network created from a 3d object applies the vertex elevations to the pipe centerline instead of the pipe invert.

If i have survey shots that pick up the pipe invert...

and a user defined property for pipe diameter that they guys input in the field

and i make some sort of expression that adds the pipe diameter to that invert..

then swap the user defined property for the Z elevation (like that wonderful scripted demo from 2 years ago did with the soil elevations)

then i connect the dots with a feature line...

everyone will be happy?

(kinda like what we do with desc keys autosizing tree diameters, ya know?)

right now, in the cases where i do this, i connect the dots then drop the feature line. but that is annoying to me and sometimes a difficult paper trail to follow. i'd like it to be somewhat automatic-ish if possible.

yours in civil 3d,

dana