One can think of structural members as objects made using **extrusion** - a term used in manufacturing. To demonstrate this, say we are to create a rectangular boxed member:

Let's say we have a 2D cross-section - a rectangle. To create a boxed structural member using extrusion:

- First, define the member's ends, points \(A\) and \(B\).
- Then, create any path between these points (provided they don't intersect)
- Pass the 2D rectangle from \(A\) to \(B\) along the route.

## Properties

### Straight and Non-Straight

Based on the extrusion path, we can identify members as either straight or non-straight. If the shape traveled from point \(A\) to point \(B\) in **one direction**, it is a straight member.

If the shape traveled from point \(A\) to point \(B\) in **multiple directions**, it is a non-straight member.