Rune Circles and Movement

[Ruethgar]

So, a rune circle specifically says that any movement would ruin it, but if D&D worlds are anything similar to reality, then there is always movement. The planet goes around the sun and spins on its axis, the molecules vibrate as part of their nature or more noticeably vibrate with any sort of sound, the tectonic plates move over time. You get the point, lots of movement.

So what level of movement is reasonable to allow? Planetary? City wide? Island wide? Molecular?

[Fouredged Sword]

The default generic 3.5 mythology has the world as an non-moving flat plane, not a globe. The sun rises and sets by itself. Motion is not relative, as there is a fixed reference plane.

[Slipperychicken]

if D&D worlds are anything similar to reality

There's your problem. If D&D worlds were similar to reality, then immovable rods would soar off into space when used (as they would remain in place while the planet quickly moves away from them), falling objects could do a lot more than 20d6 (rules compendium put a hard cap on the total damage from both weight and falling), and terminal velocity would not occur at 200ft.

[Ruethgar]

Immovable rods and rune circles... instant air conditioners as they must be at 0 kelvin to halt molecular movement.

[Afgncaap5]

So, a rune circle specifically says that any movement would ruin it, but if D&D worlds are anything similar to reality, then there is always movement. The planet goes around the sun and spins on its axis, the molecules vibrate as part of their nature or more noticeably vibrate with any sort of sound, the tectonic plates move over time. You get the point, lots of movement.

So what level of movement is reasonable to allow? Planetary? City wide? Island wide? Molecular?

Depends on the runic circle. Like rods and constructs, there are many differences in application (and pricing, for that matter.)

I would assume that if a character's movement has less of an impact than a five-foot step, it's fair.

Heck, I'd probably house rule that if the runic circle is large enough to encompass more than a five-foot space, any movement that remains within the circle should count, but that's just a house rule for me.

[Fouredged Sword]

Actually a immovable rod would also be a perfect insulator on top of being at absolute zero. It would be cold, but it would also prevent all heat transfer as all energy would be reflected completely. This would, incidentally mean that it would be mirrored when activated.