Hi,
Unfortunately, "big brother" has me locked out from viewing the video you provided a link to, so I'm flying blind here.
Retracing some steps.
1) You are in Site Modeler (SM)
2) You have 2 intersecting roads that have the edge of pavement tangents drawn in plan and their elevation assigned inside SM - probably projected from the appropriate centreline element?
3) You have the curb return graphic drawn in plan view and the preliminary elevation assigned to the return by draping it onto the Model or Object via end points?
Correct so far??
So you then open the SM>Elements>Edit Profile tool.
You have the Active Profile Control tool box open.
1) You right click on the Profile Cell Status button and select Profile Cell Setting tool.
Profile Cell Setting: Click Add Element PCell Chain tool (top left of dialog) and select (in order) the plan elements: Tangent, return, tangent.
These should highlight as you select them.
2) Once the selection of the elements is complete, you need to data point (DP) in a clear piece of the screen - you should have a second view window open and you would DP in that second view. It should draw a profile cell and the profile view of the 3 SM elements you selected.
On the Active Profile Control dialog, there should now be 2 view buttons that have activated showing which view has been assigned to Plan and which view has been assigned to Profile for the selected SM elements.
3) Active Profile Control: Select the Vertical Component Tools - which opens a tool pallet containing the vertical tools.
Place your vertical components within the vertical profile view across the section of profile you wish to redefine... typically this is the return and, possibly, some portion of one of the tangents.
4) Once the proposed profile has been drawn, you now select the Define Site Element Profile tool.
Select the first of the proposed profile elements (profile view) and keep clicking.
Its should string the profile elements together, and then apply the new profile to the appropriate portion of the SM elements.
This should then trigger a rebuild of the Site Object and Site Model AND then redraw the profile view of the 3 elements to reflect their new elevations.
And, in theory, that's it.
There are options on the Profile Celle Settings dialog to store the SM elements as a COGO Chain and Profile - if you need that.
But that should be it.
If those steps don't appear to be working, you may need to contact Support and see if one of the Support folks can help out.
There have been data situations where the tool fails, but they are rare.
Also, all the elements (plan and profile) need to have their end points co-incidental... ensure they are.
HTHs
Michael