Aiming a spell: Grease

Question

This spell lists its Area as a 10-ft. square, without it being one of canonical burst, emanation or spread. This is OK - there may be spells which aren't those things.

For area of effect spells in general we have the following statement:

Regardless of the shape of the area, you select the point where the spell originates... The point of origin of a spell is always a grid intersection...

The issue is it is unclear to me how to determine what intersection should be a point of origin for Grease spell. Should it necessarily be a center of 10-ft. square mentioned? It is unlikely, but should it be some corner of caster's space (so said caster must have line of effect to every 5' square she wants to affect)? Can aforementioned 10-ft. square partially go beyond spell's range, as an area with a 'burst' kind can?

Answer 1

The 1st-level Sor/Wiz spell grease [conj] (Player's Handbook 237) has the entry Target or Area: One object or a 10-ft. square, so, for our purposes, an entry of Area: 10-ft. square. The caster picks as the grease spell's point of origin a grid intersection within the grease spell's short range (25 ft. +5 ft./2 levels) and the grease effect is created in each square that touches that point of origin, creating a 10-ft.-by-10-ft. horizontal plane suitable for cooking pancakes or making ogres stumble.

An area spell's caster needs line of effect only to the spell's area's point of origin: "You must have a clear line of effect to the point of origin of any spell you cast, such as the center of a fireball" (176). The caster does not need line of effect to all four squares that are to be affected by the grease spell's area, for example.

An area spell's area can't typically extend beyond the spell's range. The Player's Handbook on Range says, "If any portion of the spell’s area would extend beyond [the spell's] range, that area is wasted" (175). This means, for example, the 3rd-level Sor/Wiz spell fireball [evoc] (PH 231) will typically create a half-circle if the caster picks as the spell's point of origin a point that is at end of the spell's maximum range, and a grease spell will typically only create a 10-ft. wide yet 5-ft. long slick if the picked point of origin is at end of that spell's maximum range.

This DM treats area spells like the grease spell that possess areas of Other ("A spell can have a unique area, as defined in its description" (176)) as bursts unless the spell says to treat them differently, a burst feeling to this DM like the default way effects should behave. Thus, in this DM's campaigns, a grease spell's area won't wrap around a corner like the spread of a fireball spell, but ask your DM.

Answer 2

No, you can't.

The first paragraph of AIMING A SPELL (PHB, pg.175) says:

You must make some choice about whom the spell is to affect or where the effect is to originate, depending on the type of spell. The next entry in a spell description defines the spell’s target (or targets), its effect, or its area, as appropriate.

And the start of the Area section:

Regardless of the shape of the area, you select the point where the spell originates, but otherwise you don’t control which creatures or objects the spell affects. The point of origin of a spell is always a grid intersection.

As you can see, in an area spell, the only thing you can choose is the point of origin and this point must be inside the spell range. But if you read the first paragraph of Range (PHB pgs. 174-175):

A spell’s range indicates how far from you it can reach, as defined in the Range entry of the spell description. A spell’s range is the maximum distance from you that the spell’s effect can occur, as well as the maximum distance at which you can designate the spell’s point of origin. If any portion of the spell’s area would extend beyond this range, that area is wasted.

Based on that, you can't aim the origin of the spell at the maximum range to extend the effect over the spell maximum range. It clearly says that any area over the spell range is wasted.