6e distance is fundamentally different from 5e

5e is hex based. 6e is not. This is a pain in the butt and means that the recent changes to AOE, while "right" for 5e, are wrong for 6e.

It would also be nice if we could provide some kind of interoperability between 5e and 6e.

This means that calculations for 5e are fundamentally different from those in 6e. Investigate:

AOE
- 5e AOE needs custom templates for radius, flat cones, etc. The attacking character's hex is always 1".
- How does size affect the AOE template? Presumably all of the character is 1".
- 6e needs to handle gridless and any possible grid that the game uses. It has rounded cones.
- How does size affect the AOE template? Presumably it continues to use the centre of the character as the start point for a no range AOE.
Range
- 5e range is a count of hexes with the attacking character's hex counting as 0".
- 6e needs to handle gridless and any possible grid that the game uses. Perception should start at the edge of the character (0.5m radius from centre of character)

See:

Note that many assumptions about size of the individual for 5e and 6e need to take their size into account:

dmdorman / hero6e-foundryvtt