Inspired by my previous question, I've begun to feel that life might be easier if I just had every spell be able to target both creatures and objects with attacks, and damage objects as well as creatures in their radius.
This would, for one, force players and enemies to be far more careful about the placements of their areas of effect or risk widespread destruction, but I wonder about the other potential disastrous consequences.
The game has been balanced around the assumption that objects are hard to destroy unless they are explictly targeted. It makes the game simpler.
The effects that damage objects are intentionally few and far between. For example Shatter specifically damages objects, while the spell Blight does not (unless the object is a plant). Because of this you will need to consider which damage types will damage objects and which won't.
For example:
You will need to track which objects are in range of the spell, what they are made of, and what vulnerabilities and resistances each object has. Taking all of this together means you need to be more meticulous when you map out individual environments, with exact placements of objects.
If all AoE spells damage objects, then they will also damage buildings. Damaging buildings is something spellcasters in particular will want to avoid (espescially if they are in them). As a result you would expect magic users to want to limit the damage they do to structures.
Any self respecting adventurer wants to maximise loot gained and minimise the effort to get that loot. AoE spells satisfy both of those criteria, but only if they don't damage the loot. By making these types of spells damage objects you are changing the motivations of the generations of spellcaster who went before your players.
Changing their AoE spells to cause damage to objects will mean your players end up damaging their loot. The two potential effects of this are:
Neither of these outcomes will necessarily be fun for your players (or at least for most players). Battles with lots of enemies will be harder and/or the players will get rewarded less for having those battles.
Not necessarily, but I would recommend talking to your players and seeing if they will enjoy the change.
Ultimately when we play D&D we are playing a game, not a reality simulator. The aim of games is to make sure everyone playing has fun (including the DM). If a homebrew rule change is implemented that potentially could make the game less fun for the players, that change needs to be discussed.
The flip side of this question is, of course, does the suspension of disbelief caused by not having this change make it less fun for you as the DM?
Only you can answer this question, but it should form part of the discussion you have with your players.
Yes. Chapter 8 of the gives a table which sets out different levels of improvised damage, with suggested examples. Using this table, along with the damage output by the spell or AoE effect, is the place to start.
A monster or effect typically specifies the amount of damage it deals. In some cases, though, you need to determine damage on the fly. The Improvising Damage table gives you suggestions for when you do so.
There are no disasterous side effects to allowing damaging spells that deal an appropriate sort of damage to also damage unattended objects, as appropriate to their effects. This GM does so regularly and it has not been an issue. This GM has not allowed psychic damage to damage mundane objects, generally, but otherwise has fairly extensive experience with such a house rule.
When implementing such a rule, it's usually important to decide beforehand what sorts of materials, in general, are vulnerable to what sorts of energy types. For example, this GM generally rules that metal objects take 1/4 damage from fire attacks, after damage reduction, while wooden objects ignite and take an exta 1-2 d6 of damage per turn until destroyed. Even without rules like these, though, nothing in the system is going to break, the damage dealt by energy attacks is just going to be a bit weird, and fighting near treasure will be a problem even when players might initially expect it not to be (e.g. Cone of Cold destroying a pile of coins).
Obviously, when implementing such a rule, dungeon sections will take more damage. This isn't complicated or hard to track-- I usually note the damage done directly on my gm version of the dungeon map-- and doesn't really slow down or complicate the game in any way except when you as the GM want it to, in my experience, but it is something that will happen. It is, of course, already the case that dungeon sections can take damage from, e.g., pickaxes or the shatter spell, but this rule will make collateral damage (i.e. damage incurred incidental to the real aim of an effect) much more common.
Generally, including attended objects (i.e. worn or carried stuff) in such a ruling does complicate the game, because PCs often have a great many objects on their person and determining if any and, if so, which and to what extent these objects are damaged can be excessively time consuming. Also peoples clothing blows up long before they are particularly injured which can be distracting from a campaign's narrative.
For these reasons as well as for better narrative sense (we feel that just as the legendary hero has more hp than a commoner, so too do his clothes and armor somehow survive exposure to effects that would kill the latter man), this GM generally has attended objects save as their wielder when specifically targeted by an effect and be immune to any effect not specifically targeting them unless it also kills their wielder outright (i.e. deals more than their hp maximum in damage). This is a ruling that's built out of playing a good amount, though, and so is pretty complicated. "Attended objects don't take damage" also works fine, it's just a coarser level of detail; again nothing particularly breaks.
Honestly, the few times we've done "Attended objects take normal damage" it hasn't been a game-breaking problem either, because PCs tend to be extremely paranoid about taking anything of value into the dungeon after their first fireball or gelatinous cube, but the additional complexity does significantly slow down the game.
