Questions about targeting areas spells

[Lost in books]

So these are the questions:

1) If I use a spell with a radius such as Shard Storm of 20' radius (SC, pg 187) can I cast it 30 feet of the ground as long as I have LoS? the only rule description I find is you must select an intersection to originate but it doesn't specify if it has to be on the ground only.

2) If I can cast it in the air (especially when dealing with flying creatures) shouldn't I be able to select the orientation plane the spells radiates into? so instead of casting it parallel to the ground just covering a 5' thick vertical space on a 20' horizontal spread could I be able to declare it is 5' horizontal and 20' vertical like a wall? I am not sculpting the spell just changing the orientation of it's axis.

Any clarification or pointing to the relevant rules will be greatly appreciated.

Scenario: We were being chased by gargoyles and we entered a cave with a 15 foot wide entrance so I wanted to place the spell in front of the entrance vertically.

edit: D&D 3.5 rules

[Crake]

So these are the questions:

1) If I use a spell with a radius such as Shard Storm of 20' radius (SC, pg 187) can I cast it 30 feet of the ground as long as I have LoS? the only rule description I find is you must select an intersection to originate but it doesn't specify if it has to be on the ground only.

2) If I can cast it in the air (especially when dealing with flying creatures) shouldn't I be able to select the orientation plane the spells radiates into? so instead of casting it parallel to the ground just covering a 5' thick vertical space on a 20' horizontal spread could I be able to declare it is 5' horizontal and 20' vertical like a wall? I am not sculpting the spell just changing the orientation of it's axis.

Any clarification or pointing to the relevant rules will be greatly appreciated.

Scenario: We were being chased by gargoyles and we entered a cave with a 15 foot wide entrance so I wanted to place the spell in front of the entrance vertically.

edit: D&D 3.5 rules

It doesn't say anywhere in the spell that it's a circle. When working in 3D, 20ft radius means 20ft radius SPHERE, so orientation isnt a thing to consider, because a sphere is the same no matter how you orient it. And yes, you can target intersections above the ground. Makes spells like legion of sentinels hilarious in open areas or where the ceiling is high, since you get a double layer of sentinels.

[tyckspoon]

1: yes, you can place the origin of a spell at any point within its range in any direction both horizontally and vertically. The only usual exception is some kinds of conjurations (like Summon Monsters) where the conjured thing must be placed on a surface that can support it.

2: by default an area given as a radius describes a sphere. Examples and battle maps are often drawn as if only a 2d plane exists, but everything in D&D happens in all three dimensions unless noted otherwise (eg, the area of your spell was given as a circle, not a radius, or the spell description stated it was a plane and not a circular burst.)

[Lost in books]

1) So if the spell says 20' radius spread, as long as I account for the corners, I could cast it in the air pretty much covering a 40' diameter? So it looks like a sphere?

2) But a spell like fog cloud that specifically states a height of 20' and a radius of 20' will look like a pancake 40' diameter but only 20' high? Could I control the axis of such spell or because it says 20'high I can't turn it on its side?