Step by step instructions cause Pro/E is still stuck in the past.
I find that it helps adding a column for Feature Parameters to Model Tree and enter VALUE as the Parameter to show.
After defining the Curve Length measurement you can hit the AddFeature button and save an analysis feature. You'll have to edit this after the fact if you want to use Value as the parameter name.
Easy method - Use Analysis > Measure
Option1
Curve/Chain
* Hover over sketch curve and Right Click until entire loop is selected
Option2
Chain
* Hold down CTRL Key and pick 2 neighboring entities in sketch
* Hit Next in side menu and then select after entire loop highlights
Option3
Feature
* Pick sketch feature from screen or Model Tree
Which ever above option you used hit the
Add Feature button. Enter a name for the Analysis feature A1 or CurveLength.
After analysis feature is Created you can Edit Definition
and select from options to create Parameters or change parameter names. I usually use VALUE as the parameter to create because you can show multiple values for different Analysis types.
The Default Parameter name is Length or Area or Distance depending on Analysis. To change this expand
[+]Result Params tree branch and the Parameter Type
[+]LENGTH
Double Click Parameter Name and enter the value for the Name and hit Enter then hit the check mark to Finnish the Feature definition.
Difficult Method write Relations in sketch relating to reference dimensions for line lengths and arc lengths
A1len = pi*rsdA1(sdA1/180) where
rsdA1 is Radius Sketch Dim value for Arc 1
sdA1 is angle of arc.
For a Slot like yours
d## = L1 + L2 + A1 + A2
If you write a relation for dimensione length sd## of a construction line you can edit the Dimension while in the model and add Text in properties as
CURVE LENGTH
@D
so it's visible in sketch and model
I prefer the former method with the feature because it's easier to accomplish and will update if the Sketch Feature changes.
Michael