Does the 1-2 diagonal count reset on each move action?

Question

In Pathfinder and 3.x (and possibly other systems I imagine?), diagonal movement is handled by a 1-2 rule to simplify calculation; first diagonal move is 1 square, then 2, then 1, and etc. But what happens if you end your move on a 1-square step?

For example, let's say somehow you have speed of 35 ft., or 7 squares. How many squares could you move diagonally in a single round? If you consider each move action separately, then you would end up with 10 squares, as you could move 5 squares (1-2-1-2-1 = 7) in a single move action. However, if you consider both consecutively, you'd only have 9 squares (1-2-1-2-1-2-1-2-1 = 13, and since the next diagonal move would be 2 squares you can't take it).

I can see arguments both ways via RAI: On one hand, it makes sense to consider a double move as one long move taken over the course of two separate move actions. But on the other it seems strange that you'd move less in a single double-move round than you would in two single-move rounds (Unless it persists across rounds even? But that seems crazy in terms of bookkeeping.)

I'd lean towards saying it does reset after a move action for simplicity's sake, but I was curious if there was any RAW answer for this in either 3.5 or Pathfinder. (Or 3.0 even, if there's one digging that far back.)

Answer 1

This tangle can be cut through by noting two things:

1. The diagonal rule doesn't apply to movement actions, it applies to measuring distances. (PHB, p. 147)

2. The distance you can move in a round is measured depending on what you're doing, not the number of actions used to do it. Note “Movement in Combat” (PHB, p. 147) talks about total distances, not adding together distances per action used. To think of it another way, D&D 3.5e treats the real-feet distance as primary and only translates it into grid measurements at the last moment, and so too the diagonal rule is applied after the foot-measure of a distance is established.

This means that a double move, being one continuous movement at “hustle” speed, doesn't reset the count — the two move actions add up to 70 ft. of movement and only then are translated into diagonal squares moved.

To determine how far that one continuous movement gets you, you measure 2× 35 ft. (that is, 14 squares) from your starting position, counting diagonals using the 1-2 rule. Moving entirely on the diagonal then allows you to measure a final distance-reachable of 9 diagonal squares, which you then achieve using two move actions.