Evaluate Feature

I want to use an evaluate feature in a relation but can't seem to get the context for the evaluation feature right. Online helpsays:
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Using relations, the Evaluate feature is used to create features in other models that are dependent on the measurement parameters.
Use one of the following formats to access measurement values in relations:
measurement_name:fid_N
...or...
measurement_name:fid_feature_name
In these formats, measurement_name is the name of the measurement within the evaluate feature, N is the internal feature identifier number (obtained by using Info), and feature_name is the name of the evaluate feature.
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I've tried all combinations of this but i keep getting relation errors.

"Feature > Create > Evaluate". It asks you for the name of the feature, eg. "dist". Then it asks you for the type of measurement and you give it a name, eg."dist". You can now use this feature in a relationship:


d1=dist:fid_dist

Thanks. I knew that much. What took me a while to figure out is that I have to put "fid_" in the reference.

It does seem like an archaic way of doing things, but I think it is done because one evaluate feature can have more than one measurement, thus fid_