When you have a physical member, such as a beam, the beam remains as one member, regardless of how many additional beams intersect it. Analytical members react differently than physical members.

For example, when you have two physical members like a beam and a cross beam that meets it in the middle, you still have two physical members. But with analytical members, each end plus each intersection are treated the same. Nodes are placed at ends and intersections; the result is that when you have an intersection, you have a design that could look like this:

The sequential 1, 2, and 3 are the member numbers. By looking at this drawing, you can tell that the first beam was drawn along the X-axis, and it was drawn from left to right. The second beam, along the Y-axis, was drawn from the intersection to its end, and it split the first beam into two parts. Since the first beam was there first, it is now made up of members 1 and 2. Member 3 is the intersecting beam. One important point to understand is that once an analytical member exists, it does not lose its member number. For example, if your next cross beam splits the current section 2 into two parts, then the following action occurs:

The node numbers are added in the order in which they were entered on screen. And while the member numbers look like they are not added in the same order, they really are. Existing member numbers cannot be changed, and so it is logical that the last part of the original beam becomes 4 rather than 3, since 3 is already used. The second intersecting beam becomes member 5.