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Lord Vukodlak
2010-03-22, 01:40 AM
Alright the Genesis spell creates a demi-plane coterminous with the Ethereal Plane.

Now what Coterminous means is the two planes actually touch one another and its possible to walk from one plane into the other. The DMG example is the sailing on the river Styx from Hades to the Abyss.

So the question is, if you make your own personal demi-plane via the genesis spell.

Now lets leave out any discussion of the insane and crazy traits some argue you can give to the plane, please make another topic if you want to talk about that.

For here the question is, where on a demiplane created via the genesis spell is it coterminous with the Ethereal (or Astral in the cast of the psionic version). The point of origin in the center? the edges?
One point on the edge?

Deca
2010-03-22, 01:46 AM
It's your demiplane so I'd say it'll join the Ethereal wherever the hell you say it does. You designed it after all.

Lord Vukodlak
2010-03-22, 02:36 AM
It's your demiplane so I'd say it'll join the Ethereal wherever the hell you say it does. You designed it after all.

You do design it but traits are set when you make it and the plane grows over time which complicates where it could be. If it simply created a 180ft radius demi-plane you could set the entrance anywhere.

JaronK
2010-03-22, 04:05 AM
I was under the impression that the ethereal behaves a little differently, in that anything coterminous with it is coterminous everywhere, but you have to cast an appropriate spell (such as Ethereal Jaunt) to get there. On a plane that's not coterminous with the ethereal such spells simply fail to work.

JaronK

Lord Vukodlak
2010-03-22, 05:05 AM
I was under the impression that the ethereal behaves a little differently, in that anything coterminous with it is coterminous everywhere, but you have to cast an appropriate spell (such as Ethereal Jaunt) to get there. On a plane that's not coterminous with the ethereal such spells simply fail to work.

JaronK

Well the only example of Coterminous Planes is the sailing from Hades to the Abyss which implies one can simply walk between them at certain points. Coexistent Planes, two planes that overlap such as the Ethereal and material plane do.
Wish I still had my old Manual of The Planes sure its 3.0 but it gave much better details of planar mechanics then the 3.5 DMG and the Planar Handbook combined.

Zeta Kai
2010-03-22, 05:18 AM
The SRD is quite clear on how planes interact (http://www.d20srd.org/srd/planes.htm#howPlanesInteract).

Optimystik
2010-03-22, 06:54 AM
For here the question is, where on a demiplane created via the genesis spell is it coterminous with the Ethereal (or Astral in the cast of the psionic version). The point of origin in the center? the edges?
One point on the edge?

Manual of the Planes goes into depth on your questions in the "Transitive Planes" section.

1) The Astral Plane and the Ethereal Plane are actually two separate planes. They aren't the same one with a "magic name" and a "psionic name."

2) There are three transitive planes, of which the Astral and Ethereal are two. (The Plane of Shadow is the third.)

3) The Astral Plane is coterminous with all other planes (i.e. it touches all of them, making travel possible, but it has its own properties.) The Ethereal plane is coexistent with all other planes (it is overlaid on top of all of them, except the Plane of Shadow. This again makes travel possible, but it inherits some of its properties, like gravity, from the plane of origin.)

4) The Plane of Shadow is both coterminous and coexistent with the Material Plane, and only coterminous with most other planes (so long as there are areas of darkness on them) and never touches the Ethereal Plane directly.

Lysander
2010-03-22, 09:25 AM
My interpretation is that your plane hangs suspended in the ethereal plane like a snowglobe. You're not so much making an entirely new universe as you are altering the environment and physical laws of part the ethereal plane.

Here's what makes me believe that:


A character can only cast this spell while on the Ethereal Plane. When he or she casts the spell, a local density fluctuation precipitates the creation of a demiplane. At first, the fledgling plane grows at a rate of 1 foot in radius per day to an initial maximum radius of 180 feet as it rapidly draws substance from surrounding ethereal vapors and protomatter.

So the plane is a "local density fluctuation." That means everything in your plane, rocks, mountains, water, air, etc., is made from random particles in the ethereal mists that were brought together by the genesis spell.

The plane is surrounded by ethereal vapors and protomatter. So there isn't a single door shaped portal somewhere, you have the ethereal plane in any direction you go. Fly high enough, you'll enter the ethereal plane. Burrow deep enough, you'll go through the ground and into the ethereal plane.

Since the planes are coterminous at every point along the demiplane border that means that creatures can freely move in and out at any point. Which means you better have some kind of security around your demiplane if you don't want random ghosts walking in.

Yora
2010-03-22, 09:47 AM
I rather tend to think that the demiplane is connected to the ethereal plane, but not to the material plane. So you have to pass through the etheral to get from the material plane to the demi-plane.

And I'd say the location of the demiplane is centered on the same spot where there spell ist cast.

Lord Vukodlak
2010-03-22, 10:20 PM
Manual of the Planes goes into depth on your questions in the "Transitive Planes" section.

1) The Astral Plane and the Ethereal Plane are actually two separate planes. They aren't the same one with a "magic name" and a "psionic name."

I never said that,
The psionic version of the genesis spell creates a demi-plane while your standing in the astral plane, the arcane/divine version creates one while on the Ethereal plane.

And nothing you said actually answers the question of how exactly is the genesis created demi-plane "connected" to its mother plane.


The SRD is quite clear on how planes interact (http://www.d20srd.org/srd/planes.htm#howPlanesInteract).

And the DMG which is more expansive gives the one example of Coterminous Planes as sailing from hades to the abyss. Which leaves one to believe that two planes that are coterminous can literally be walked from one into the other.


My interpretation is that your plane hangs suspended in the ethereal plane like a snowglobe. You're not so much making an entirely new universe as you are altering the environment and physical laws of part the ethereal plane.

Since the planes are coterminous at every point along the demiplane border that means that creatures can freely move in and out at any point. Which means you better have some kind of security around your demiplane if you don't want random ghosts walking in.

Assuming we use your snowglobe theory, a ghost wandering in would be interesting. The demi-plane is coterminous with the ethereal but not coexistent. Normally a ghost is present on the Ethereal plane unless it manifests in which case it appears incorporeal on the material while still maintaining a presence on the Ethereal.

If it entered your personal plane by passing the border it would no longer be present on the Ethereal plane at all. Far different then simply manifesting.

If it walked beyond past a border into a demi-plane that would mean leaving the ethereal plane completely. Which actually makes me wonder COULD a ghost completely leave the Ethereal plane behind?
First it lose its ability to manifest the dem-plane is not coexistent with either the Ethereal or material plane. It simply touches the Ethereal plane.

Looking at the savage progression for the ghost, shows its flight is a result of it being on the Ethereal plane[remember its still on the Ethereal plane even when it manifests on the material] So a ghost pulled completely form the material plane couldn't fly, Other abilities from the template assume the ghost is either manifesting or its fighting another creature on the Ethereal plane.

Optimystik
2010-03-22, 10:25 PM
And nothing you said actually answers the question of how exactly is the genesis created demi-plane "connected" to its mother plane.

You asked "where does it connect to the Astral Plane" to which I answered "everywhere."

The Astral Plane is literally the space between planes. The only way not to touch it on a given point, is to have your demiplane juxtaposed to another plane at that point.

Lord Vukodlak
2010-03-22, 10:35 PM
You asked "where does it connect to the Astral Plane" to which I answered "everywhere."

The Astral Plane is literally the space between planes. The only way not to touch it on a given point, is to have your demiplane juxtaposed to another plane at that point.

Everywhere means coexistent the planes overlap, Coterminous simply means the planes are connected in someway but not everywhere.

Either version of the genesis spell creates a spell that is Coterminous to the mother plane, in the divine/arcane its the Ethereal but in the case of the psionic power its the Astral.

Lysander
2010-03-22, 10:39 PM
Assuming we use your snowglobe theory, a ghost wandering in would be interesting. The demi-plane is coterminous with the ethereal but not coexistent. Normally a ghost is present on the Ethereal plane unless it manifests in which case it appears incorporeal on the material while still maintaining a presence on the Ethereal.

If it entered your personal plane by passing the border it would no longer be present on the Ethereal plane at all. Far different then simply manifesting.

If it walked beyond past a border into a demi-plane that would mean leaving the ethereal plane completely. Which actually makes me wonder COULD a ghost completely leave the Ethereal plane behind?
First it lose its ability to manifest the dem-plane is not coexistent with either the Ethereal or material plane. It simply touches the Ethereal plane.

Looking at the savage progression for the ghost, shows its flight is a result of it being on the Ethereal plane[remember its still on the Ethereal plane even when it manifests on the material] So a ghost pulled completely form the material plane couldn't fly, Other abilities from the template assume the ghost is either manifesting or its fighting another creature on the Ethereal plane.

That is a good question. What would happen, for instance, if you plane shifted a ghost from the ethereal to material planes? Would it become a corporeal undead? Or would it remain incorporeal but only exist on the material plane?

Lord Vukodlak
2010-03-22, 10:44 PM
Well a ghost is corporeal to other creatures on the ethereal plane. If you went to the Ethereal plane to combat a ghost it be solid.

It is only incorporeal when using its manifestation power to appear on the material plane. So if you planeshifted it completely to the material. Well it be solid because it wasn't manifesting.

Lysander
2010-03-22, 10:52 PM
Well a ghost is corporeal to other creatures on the ethereal plane. If you went to the Ethereal plane to combat a ghost it be solid.

It is only incorporeal when using its manifestation power to appear on the material plane. So if you planeshifted it completely to the material. Well it be solid because it wasn't manifesting.

So a ghost could walk into your plane as a corporeal creature. Once inside it couldn't fly (except by other means) but would retain other ghostly abilities. You'd definitely want to have sentries floating in the void around your plane. You could also encase your entire plane in magical walls to keep intruders out.

Lord Vukodlak
2010-03-22, 10:57 PM
Most of them anyway, it lose Malevolence and perhaps a few of the expanded abilities from Libris Mortis, and its touch attacks would use strength instead of dexterity on attack rolls.

Of course depending on from where the ghost enters it might actually die. If it entered from the vary top it could fall 180ft and splat on the ground. Given it become a corporeal undead, standard walls might be sufficient.

Lysander
2010-03-22, 11:49 PM
What they could do is actually build a defensive perimeter in the ethereal plane. If the plane has a 180ft radius they could build a globe with a 200ft radius. Perhaps with repeated castings of Wall of Iron. If they have xp to burn they could surround the whole thing with permanent walls of force. Or use a gate spell to bring mundane building materials in. There could be a few heavily guarded gates to let ethereal travelers in.

Or when you design your plane just design it as a hollow ball of stone with gravity pulling things away from the center. That forces creatures to tunnel upwards to get to you, which you can make difficult by having a legion of creatures floating around the outside preventing intrusion.