When is the HO called for lines across the center?

When is the HO called for lines across the center?

• A. When the first floor passes the center
• B. When the second floor just passes the center
• C. When the second floor reaches the center
• D. When the bottom line passes the center

Answer: (B)

The important idea here is how centerlines are used to show alignment between levels in a multi-story drawing. You only start drawing a line across the center when the upper level begins to cross that centerline, so the line can clearly indicate how features on the two floors line up. So the moment the second floor just passes the center is the moment you begin this cross-center marking. It’s the first point at which the two levels share the center area in a way that needs a continuous centerline to communicate alignment. If the second floor hasn’t reached the center, there’s nothing to connect; if it has already fully crossed, the line would already be established. The other options describe thresholds that don’t correspond to this alignment cue.

The important idea here is how centerlines are used to show alignment between levels in a multi-story drawing. You only start drawing a line across the center when the upper level begins to cross that centerline, so the line can clearly indicate how features on the two floors line up.

So the moment the second floor just passes the center is the moment you begin this cross-center marking. It’s the first point at which the two levels share the center area in a way that needs a continuous centerline to communicate alignment. If the second floor hasn’t reached the center, there’s nothing to connect; if it has already fully crossed, the line would already be established. The other options describe thresholds that don’t correspond to this alignment cue.