ELEMENT TEMPLATES AND FEATURE DEFINITIONS

Question

Hello, 
 We are using Microstation SS3 and Power InRoads SS3 / SS2. 
 We are trying to understand the concepts behind the role and purpose of element templates compared to feature definitions. 
 We see that a feature definition is assigning specifically a symbology and element template to an object. But find some confusion when observe that the element template also appears to assign "symbology-like" settings such as level to an object, but does offer more settings. So it seems there is some redundancy in how an object is defined, at least as far as defing the level twice. Is there a hierarchy of control between the element template and the feature definition as far as level or any other redundant setting?

Robert Garrett · Accepted Answer

A Feature Defintion is composed of two parts: 
 
 The "feature defintion" which defines the nature of the feature being defined. For example, it is an edge of pavement, or it is a curb. These are rather ordinary, I suppose since there is not a lot to descirbe them other than "I am a curb". But, coming soon, you will see examples such as catch basin, where the feature defintion part will not only decribe what I am but also contain the hydraulic characteristics of the catch basin. Or, a Pipe, where the feature defintion describes the various available pipe sizes. 
 The element template defines the symbology. More specifically, it describes its presentation. For example, I am blue. Or I am on level whatever. By assigning different element templates for different views (plan, profile, 3D) then the same feature can be presented differently in each context. In the future, you might imagine that the in addition to plan, profile and 3D context, you might have context based on user roles. A road designer wants to see it one way, a drainage designer wants it another. 
 
 This last aspect (user defined roles) is one of the reasons that the feature defintion is in two parts. What a thing is (edge of pavement, curbe or catch basin) is always the same. But presentation can vary.