D&D 5E Silent Image and Minor Illusion size restrictions

[jgsugden]

Minor Illusion, SIlent Image, Phantasmal Force, Major Image, Programmed Illusion. These spells all have differences, but they all share some defining language when they make a visual illusion: They must be "no larger than a XX-foot cube".

How do we all play this restriction? What do we mean by larger? Is this a maximum for any dimension, or is it a volumetric concept? Is it:

FITS WITHIN: The illusion must fit within the specified space?

HAS THE VOLUME OF: It does not need to fit within the specified space so long as the volume of the illusion is no greater than the specified space?

A pole that has a width of one inch but is 50 feet long would not fit into any of these areas, so would not be eligible under the "fits within", but it has such a small volume that it would have less volume than the 5 foot cube created by a minor illusion.

If we decide on the more restrictive, what if the illusion has features that allow it to change, and the change would make it extend further than the initial "fits within" size? For example, a major image creates a 20' tall extendable ladder. If it is then extended, so that it is now 40' tall, and that entire area is within the range of the spell - what happens?

 

[Oofta]

I rule that it has to roughly fit in a 5' cube. However, the base of the cube does not need to be flat to the ground.

So a 5' square image can create something up to about 7' tall (because a**2 + b**2 = c**2). You can create a medium creature but not a 10' long pole. A standard door works because you can put the square "sideways" if that makes sense (hard to show without a picture).

Anyway, that's how I rule it.

 

[Lanefan]

Minor Illusion, SIlent Image, Phantasmal Force, Major Image, Programmed Illusion. These spells all have differences, but they all share some defining language when they make a visual illusion: They must be "no larger than a XX-foot cube".

How do we all play this restriction? What do we mean by larger? Is this a maximum for any dimension, or is it a volumetric concept? Is it:

FITS WITHIN: The illusion must fit within the specified space?

HAS THE VOLUME OF: It does not need to fit within the specified space so long as the volume of the illusion is no greater than the specified space?

A pole that has a width of one inch but is 50 feet long would not fit into any of these areas, so would not be eligible under the "fits within", but it has such a small volume that it would have less volume than the 5 foot cube created by a minor illusion.

If we decide on the more restrictive, what if the illusion has features that allow it to change, and the change would make it extend further than the initial "fits within" size? For example, a major image creates a 20' tall extendable ladder. If it is then extended, so that it is now 40' tall, and that entire area is within the range of the spell - what happens?

Were it me, I'd not only go with "Has the Volume" but probably increase the allowable volume as well: Illusion spells (and thus, Illusionists) have been absolutely hosed over the editions and now need all the help they can get!

The range would be the limiter - if your 100' "rope" down the cliff would extend 10' beyond your range it'd only be a 90' rope ending at your range limit.

 

[Unwise]

Personally I hedge bets between the two. When it says 10x10 cube. I just think of that as 4 x 5' squares on a battlemap. They can arrange those squares in any order they want. So they could make a huge 20' x 5' long snake.

 

[Bacon Bits]

I rule that it has to roughly fit in a 5' cube. However, the base of the cube does not need to be flat to the ground.

So a 5' square image can create something up to about 7' tall (because a**2 + b**2 = c**2). You can create a medium creature but not a 10' long pole. A standard door works because you can put the square "sideways" if that makes sense (hard to show without a picture).

Anyway, that's how I rule it.

Yeah that's how we have ruled it, too.

You can get a pole about 8.5 feet long if you go opposite corner (the two corners whose vertices are furthest away by tracing edges).

 

[fearsomepirate]

I take it terms of the grid. Fits in a 5' cube = medium creature. So you could make an image of a person, and I am not going to quibble about whether his head must be bowed down a few inches, since I don't really care about that level of granularity anyway.

 

[jgsugden]

Yeah that's how we have ruled it, too.

You can get a pole about 8.5 feet long if you go opposite corner (the two corners whose vertices are furthest away by tracing edges).

LIES! In D&D diagonals are the same length as orthogonal!

(Yeah, yeah - accept it is a joke and avoid the temptation to comment on all the exceptions and inaccuracies).

 

[Shiroiken]

Fit within the space, with DM interpretation for common sense. IMO exactness isn't that important, because remember most races are taller than 5 ft, yet "fit" in a 5x5x5 space. I've used them to create images of people without ever worrying about the specifics, and as a DM I'd be just as lenient.