How do the meta magic feats Heighten Spell, Sanctum Spell, Earth Spell, and Practical Meta Magic Interact?

Question

Context:

This is general theory crafting surrounding the Shadow Illusion (Su) feature of the Shadow Craft Mage in the hopes of maximizing every potential spellcasting slot a character has.

Earth Spell requires a spell to be used in a higher-level slot in order to "active" and give it's +1 spell level and +x Spell caster boost. Using Sanctum Spell we are trying to lower the effective spell level of the original spell so that easy meta magic and heighten spell can be applied on the spell in its original spell slot and receive the bonus from earth spell.

I would appreciate help in understanding if what I'm trying to do is legal and if I'm calculating this correctly.

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The Metamagic Combo:

• Heighten Spell - To Increase the effective spell level of a spell by +1 or more, increasing slot requirement.
• Sanctum Spell - To lower the effective level of the spell by -1 without a slot modifier.
• Earth Spell - To Increase effective caster level of the spell by +2, and retain out +1 to effective spell level.

The three above feats represent the core of the skill interaction I'm trying to understand. We use Sanctum Spell to preserve our Earth Spell interaction on our lowest level spell slots.

• And then we layer on either: Practical Metamagic -or- Easy Metamagic - so we can get an additional +1 to final effective spell level without increasing the spell slot used.

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The Question

If I stack one instance of all four meta magics onto the 1st level spell Silent Image is it:

A 0th level spell counted as a 2nd level spell prepared in a 1st level slot with a +1 caster level boost?

• Or -

A 1st level spell prepared in a 2nd level slot with an effective Casting level of a 2nd level spell with a +1 caster level boost?

What does this look like as I start stacking on more and more levels of Heighten Spell onto Silent Image?

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I apologize if this all seems messy - but I'm at the point I know I'm confusing myself trying to puzzle fit this together.

Answer 1

Your description of the metamagic and meta-metamagic traits confuse me a little. Here is how I think about them, first:

• Sanctum Spell effectively adds a free level of Heighten to a spell, if cast within your Sanctum, or "reverse" Heighten, if not. For instance, a Magic Missile cast as a Sanctum Spell within your Sanctum would be cast as a 2nd level spell, or cast outside your Sanctum a 0th level spell, in either case using a 1st level slot.
• Heighten Spell raises the effect and slot of a spell by one or more steps. For instance, a Magic Missile can be Heightened to a 3rd level spell, using a 3rd level slot, using Heighten Magic.
• Earth Spell adds one extra level of effect to a spell you Heighten, without requiring a higher slot. For instance, a Magic Missile Heightened to a 3rd level spell with support of Earth Spell would use a 2nd level slot.
• Practical and Easy Metamagic are basically equivalent, they both reduce the slot required to apply a metamagic to a spell, to a minimum of one. They must be bought for a specific Metamagic, i.e. Heighten Spell, and neither can be bought multiple times for the same Metamagic. They do stack with each other, though. If you have Easy Metamagic (Heighten Spell), a Magic Missile Heightened to a 3rd level spell would use a 2nd level slot. Note, however that a Magic Missile Heightened to a 2nd level spell would also use a 2nd level slot, thanks to the minimum of one rule.

Note that the first two are metamagic - they affect magic/spells - while the last are meta-metamagic - they affect metamagic. Earth Spell and Practical Metamagic are defined as General feats, while Easy Metamagic is a Metamagic feat and significantly cheaper in requirements (read: better, almost too good).

So, Silent Image as a 1st level spell (note that it would be a 0th level spell, a cantrip, if you were a Gnome Illusionist), with all these effects applied at once. Let's do them one at a time, to follow along.

• Sanctum Spell raises the effective level to 2nd level, if cast within your Sanctum, otherwise lowers it to 0th, while still using a 1st level slot.
• Heighten Spell raises the effective level and slot by n steps, let's say 2. Silent Image, cast within your Sanctum, is now a 4th (inside Sanctum) or 2nd level spell, using a 3rd level slot.
• Earth Spell, seeing as how you are already using Heighten Spell, adds another level of Heighten without requiring a higher slot. The Silent Image spell will now be cast as a 5th (inside Sanctum) or 3rd level spell, using a 3rd level slot.
• Easy Metamagic (Heighten Spell) (or Practical, but just get Easy) will let you maintain the same effect for Heightened spells while lowering the slot by one, to a minimum of one higher than the original spell. The Silent Image spell will now be cast as a 5th (inside Sanctum or 3rd level spell, using a 2nd level slot.

If, instead, you had chosen to Heighten the spell by only one step, Easy or Practical Metamagic would have had no effect. The feat(s) would, in the final step above, have tried to lower the "slot cost" of the spell from a 2nd level slot to a 1st level slot, but they "can never reduce the spell-slot cost below one level higher than the spell's actual level", to quote the Easy Metamagic description.

Answer 2

You may need the DM's permission for this to work the way you want

Picking the metamagic feat Easy Metamagic (Dragon #325 62) or the general feat Practical Metamagic (Races of the Dragon 101) to apply to the feat Heighten Spell (Player's Handbook 95) typically has no effect. The Heighten Spell feat, in part, says, "The heightened spell is as difficult to prepare and cast as a spell of its effective level." So while you can "lower the spell-slot cost [of the Heighten Spell feat] by one" with the Easy Metamagic (Heighten Spell) feat or make it so that "the spell uses a spell slot one level lower than normal" with the Practical Metamagic (Heighten Spell) feat, because the spell is still being modified by the Heighten Spell feat, the spell remains as difficult to prepare and cast as a spell of its effective level. The Heighten Spell feat is unique in this regard, no other official metamagic feat sharing its as difficult to prepare and cast language.

In other words, the Heighten Spell feat stops a caster from using other game elements in conjunction with itself to, for example, employ a 1st-level spell slot to prepare or cast a 2nd-level or higher spell. Because it's important, here's that a third time: "The heightened spell is as difficult to prepare and cast as a spell of its effective level." To sum: It doesn't matter by how much a spell would've been heightened for free, the heightened spell's heightened level determines the level of the spell slot into which it can be put (or that must be expended to cast it).

Further, the Easy Metamagic feat, in part, says, "You can never reduce the spell-slot cost below one level higher than the spell's actual level." And the Practical Metamagic feat, in part, says that the resultant spell's spell level must be "a minimum of one level higher than a spell's normal level." This makes applying either feat to, for instance, the metamagic feat Sanctum Spell (Complete Arcane 82–3) a nonstarter: The Sanctum Spell feat doesn't normally increase a spell's level. And feat Earth Spell (Races of the Stone 138) isn't a metamagic feat at all.

If the DM says that the Easy or Practical Metamagic feats when applied to the Heighten Spell feat allow preparing and casting high-level spells using low-level spell slots, the DM will have to determine how that works.

Example: Using Earth Spell, Heighten Spell, and Sanctum Spell together anyway

A caster prepares in a 4th-level spell slot the 1st-level Sor/Wiz spell silent image [illus] (PH 279) that's modified by the metamagic feat Heighten Spell to be a 4th-level spell and that's modified by the metamagic feat Sanctum Spell.

When that spell comes into effect, if the caster's in his sanctum then that spell's effective spell level in increased by 1 to a 5th-level spell, but if the caster's not in his sanctum then that spell's effective spell level in decreased by 1 to a 3rd-level spell. Because the Sanctum Spell feat's benefit is realized upon the spell modified by the Sanctum Spell feat being cast, there's no issue with the spell's slot level.

Alternatively, when that spell comes into effect, if the caster has dirt in his shoes and the Earth Spell feat then that spell's effective spell level in increased by 1 to a 5th-level spell and the caster's effective caster level for that spell increases by +3 (i.e. the amount by which the spell was originally modified by the Heighten Spell feat). Because the Earth Spell feat's benefit is realized upon the spell being cast, there's also no issue with the spell's slot level.

However, the feats Earth Spell and Sanctum Spell are cumulative. In the sanctum and shoes full of dirt? That 4th-level silent image spell, when cast, is effectively a 6th-level spell and the caster's caster level for it is +3.

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Note: Ask the DM beforehand if dirt in your shoes is sufficient to realize the benefit of the Earth Spell feat.