Saturday, March 29, 2014

Grand Grimoire Appendix on Spell Targeting, shape, etc.

Presented as a Player's Aid. Use freely, but please link back to source. Of course, The Grand Grimoire, a book containing all the mage spells in AD&D, with over 4000 spells (far more than in the Spell Compendium), totally doesn't exist and is a myth.

 Spell Targeting and Detonation Effects, Range, Area of Effect and Spell Shape.

When calculating damage of a spell, the shape, range and area of effect are incredibly important for determining who is hit and who is not. The most commonly used shapes are the sphere, ray, cube and missile. Each of these vary based upon the range of the spell.

If the range of the spell is 0, or touch, the shape of the spell must begin at the mage’s hands, unless the spell states that it comes from another part of the body or the mage is of a race that uses something other than hands (for the rest of this appendix, the word ‘hands’ will be used to describe both hands and the non-hands used in this way, including things like spells cast from wands or staves) If the range of the spell is greater than zero, and the spell is not otherwise described as originating from the mage, the spell may start anywhere within the range that the mage determines.

In the images below, a ray-shaped spell (its size is determined by the area of effect) is cast by two mages. The first image shows a range of zero:

The second image is of a ray that can be formed anywhere within a range. Note that the start of the area of effect needs to be in the range, but the end of the area of effect does not:

Unless the spell states otherwise, ray spells may be cast at any angle the mage desires. Each of the rays below represents a potential direction a ray can go. Note that some of these rays would hit the mage, the ceiling above him or whatever he is standing on. Often (but not always) the mage must be looking in the direction his ray goes.

In addition to the shape of the spell, the mage needs to understand the movement of the spell effect, if any. Rays, for example, move away from their origin (direction is represented by the arrow), usually at the speed of light. The DM generally determines that anything within sight of the ray cannot dodge once it has fired, although prescience or knowledge of the spell can allow the targets to dodge before the ray forms.

Cones are similar to rays, but occupy a larger area. Cones can have an area of effect based on an entire cone, or a partial cone. This is described in the area of effect of the spell:

The above represents a cone that has an area of effect of an entire cone, shown here as originating at the mage. Note that a cone-shaped spell’s area of effect is given as both a length and a width at the terminal end. The terminal end is the part furthest from the mage, the part closest to the mage is called the origin. If a cone’s area of effect is described as “10ft long and 5 ft wide” the 5ft wide describes the diameter of the circle that represents the wide end of the cone, and the 10ft long describes its length:

Sometimes a cone is described as having two ends, for example, being 10 ft long, 5ft at the end and 1ft at the beginning. Here is that cone (more accurately a partial cone):

As with a ray, a cone that does not have a range of touch or zero can start anywhere in the area of effect of the spell, as shown here (this is the partial cone from above):

 Cubes and spheres can form either around the mage or anywhere in the range of the spell. If it forms around the mage, assume the walls of the cube are equidistant from the center of the mage’s body. (or that the center of the sphere is near the center of the mage:

If the cube may be formed anywhere in the area of effect, it can be tilted in any direction the mage desires (unless the cube has weight or otherwise must have a flat edge on the floor.) If the cube spell has a range of zero, but does not form around the mage, the mage must be touching the outside edge of the cube. It is most common for the cube to form with the mage near the center of an outer wall or touching a corner. The mage often has some leeway as to angles:

A very common form of spell effect is the expanding cube or sphere, fireball being the most frequent form. This form starts as a dot—

—and then expands out equally from the initial sphere that appears (or is thrown). Here it is partially expanded. Note that the time elapsed in expansion often allows a save for half damage, as people within the area of effect dive for cover.

Finally, here is the expanding sphere fully expanded, taking up the entire area of effect.

In addition to the shape of the spell effect, how the mage targets it can be important. While there are dozens of targeting techniques, the most common are area effect, line of sight, touch attack and physical attack. Area effect and line of sight do not require an attack roll, and automatically hit (unless a save is allowed). A touch attack merely requires that the mage briefly touch his target, including his target’s armor, this means that the AC bonus bestowed by the armor can be ignored, but that displacement and other effects are not ignored (enemy’s DEX bonus and bonuses from shields are only allowed if he is actively avoiding the mage’s touch.) Note that held or non-resisting targets are automatically hit.
                Physical attacks are often the most risky targeting techniques for mages, because they have a low chance of hitting with physical attacks. The chance to hit is based on the target’s AC and the chance for the mage to hit as if the physical attack were a weapon he was proficient with. (A character with a THAC0 of 16 trying to hit an AC of 0 would need to roll 16 or better.)
                Understanding how a spell goes off is vital to a party’s survival. Magic Missile, for example, will swerve around a big fighter that crosses between the mage and his target, unerringly hitting the target. A fireball’s full area of effect (a sphere of 20 ft radius) cast to go off 15ft in front of the mage will easily hit the mage who cast it, and anyone between a ray of enfeeblement’s origin and its endpoint will be hit by it, regardless of whose side he is on.

Level-Based increases in Spell Power
                Many spells increase in area of effect or amount of damage as the caster’s level gets higher. Note that the caster’s level is not necessarily his actual level. For example, a bard’s “casting level” is always one level lower than his or her bard level (thus a 9th level bard casts as if 8th level,) and a swordmage’s mage-like abilities are often listed as ‘cast as if a level 12 mage,’ in which case the spell pretends the swordmage is a level 12 mage, whether his actual level exceeds that level or is beneath it. Typical Level based increases are presented below:
Type of increase
Example of listing
Example at 9th level
Example at 18th level
Additional Dice per level
1d4 per level (max 10d4)
10d4 (damage is maxed)
Base plus additional dice
100 + 1d6 per level
Additional points per level
1d6+ 1 per level*
Additional die per n level
1d6+ 1d6 per 3 levels**
Additional die per after lvl
1d6 + 1d6 per level after 10th level
Size increase-circle/sphere
radius 10ft per level
shape with radius of 90ft
shape with radius of 180ft
Size increase-cube
Cube w/10ft side per level***
Cube 90ft high, wide, long
Cube 180ft high, etc.
Size increase-cubes
One 10ft cube per level***
9 cubes, each 10ft high†
18 cubes, each 10ft high†
Size increase-Cubic Feet
100 cubic feet +10 per level
190 cubic feet
280 cubic feet
Size increase-Wall
10ft high, length 1d6+10ft per level
10ft high, 1d6+90ft long
10ft high, 1d6+180ft long
Additional number per level
Seven balls + 1 per level
16 balls
25 balls
* When written in the form of 1dN+y per level, assume that only y (not 1dN) is increasing by level unless the spell makes it explicit otherwise. For example, a spell creating one missile per level, each doing 1d6+1 damage would be written as “1 missile per level, doing 1d6+1 points of damage each” in the spell description.
** A die is added at level 3, 6, 9, 12, 15, 18, etc. See a spell’s description for how fast damage increases.
***It can be very confusing for some people to distinguish between an increase in the size of cubes and the increase in number of cubes, and can usually be demonstrated with 6 sided dice. If each die is assumed to be a 10ft cube, a 30ft cube would be made out of nine cubes, each one 10ft on a side, stacked 3 high and 3 deep-nine dice. A spell increasing by one 10ft cube per level is increasing in size slower than a spell with cubes that are growing at 10ft per level, but the character has more leeway with the position of the spell effect.
†These cubes usually must touch each other and follow logical geometry, but the player may have a lot of leeway in the shape of the effect the multiple cubes make. For example, eight 10ft cubes could make a cube 20ft high and 20ft long, a wall 10ft high and deep and 80 feet long, a shape 20ft long on one side, 40ft long on the other and 10ft high, etc.

Note that there are no partial increases. A spell that does 5 points of damage plus 10 for every two levels would do 5 at level one, 15 at level 2, 15 at level three, and 25 at level four. It would never do 10 or 20 points.