Leaving an adjacent square does not always mean leaving the reach of the weapon you intend to react with. In D&D 2024, Reach adds 5 feet to reach when attacking with that weapon and when determining its opportunity attacks. Check that reach before resolving movement in DMGrid.
Three distances in a straight line
Fictional example: a creature with the usual 5-foot reach wields a Reach weapon. For an opportunity attack with that weapon, this example’s reach is 10 feet. A visible opponent uses its movement to move straight away from 5 to 10 feet, then attempts to reach 15. The reacting creature has its Reaction available and no other effect alters these rules.
- Moving from 5 to 10 feet remains within that weapon’s 10-foot reach.
- Attempting to move from 10 to 15 leaves that reach.
- An opportunity attack with it, if taken, resolves just before the opponent leaves.
This describes the reaction with the example weapon. It does not establish that no other attack, feature or reaction can intervene earlier. Check the reach and conditions of any other options the creature has.
Check the trigger before spending the Reaction
The general rule permits an opportunity attack when a creature you can see leaves your reach, using your Reaction. Exceptions apply: Disengage avoids provoking it through that movement; teleportation and certain movement not using the creature’s movement, action, Bonus Action or Reaction do not provoke it either.
Consult the opportunity attack rule and 2024 Reach property. Do not automatically import another edition’s rule or a feature your character lacks.
Represent the decision in DMGrid
DMGrid documents a tactical board, distance ruler, pieces, turn order, hit points and session notes. Use those to support positioning and measurement. The table resolves reach and the reaction; this guide does not claim the board automatically detects Reach or stops a piece at its boundary.
- Confirm map scale and the positions from which you measure.
- Consult the weapon and note the reach for this reaction.
- Review the route and resolve any reaction at the appropriate point before continuing.
- Keep relevant results in the notes and manually update applicable state.
The cover photo is illustrative: its physical tape defines neither your map’s scale nor a screenshot of the program.
The movement circle answers a different question
A creature can have substantial movement remaining while staying within a weapon’s reach, or use little movement and leave it. Movement allowance and attack distance are different quantities. DMGrid’s walking/running circles do not replace reading the specific attack’s reach.
Consult DMGrid’s product facts and published features. It is a paid Windows beta for in-person campaigns with local data, rather than a browser multiplayer room or an automatic referee for every rule.