Does going outside the range of the spell or breaking line of sight between the caster and target break concentration or otherwise affect control over the spell?
For example, a Heat Metal spell has a range of 60 ft. If I cast the Heat Metal spell on a an armored foe, and that foe runs outside the range of the spell (60 ft), or around the corner, does that break concentration and end the spell? Heat Metal also allows you to use a bonus action to cause the 2d8 of damage — would exercising that option be prevented by being out of range or line of sight?
Best Answer
Player's Handbook p.203
QED
From your example, Heat Metal says:
There is no range or LoS limit on this - they can run but they can't hide! Distance is not a protection and (arguably) even moving to another plane doesn't help.
Given that it takes longer to get out of armour than the spell lasts (1 minute), you had better try to break the spellcaster's concentration. Make no mistake, this is a lethal spell to use on armoured opponents especially since it scales with spell slot.