[Barnacle Bill]

I definately interpret "undomed" as meaning walking around like people do on earth. You don't need breathing apparatus, you don't need any special high-tech equipment, if civilization drops back to the stone age on that planet due to some disaster the folks there can still survive (perhaps at lower population density due to food production). The "dome" thing means you can't use the surface of the planet normally and have to live in a structure with the right environment, which isolates you from the outside environment. "Undomed" means you can live normally in the outside environment.

For colonists not to go too deep in a gas giant's atmosphere, that requires that they have a way to do that. That requires they must be naturally buoyant like a fish in water, or some hypothetical critter which floats in the air like a blimp by virtue of internal cavities filled with some lighter-than-air gas. Either of those require, in addition to buoyancy, a means of propulsion without touching the ground. If they live on an artificial structure which is itself buoyant, or supported by gravity, that is a "dome". No life form that I can think of here on earth could live in the atmoshere of a gas giant, outside of a man-made artificial environment. Certainly not a human, or anything produced by genetically engineering humans if the result was to recognizable as & interfertile with humans.

If you have to live deep in the caves under the surface of an ice planet to take advantage of the heat from a molten core, that is a "dome" too, for all practical purposes.

So, I can see life forms from an rock or ice or gas giant planet being able to live on one of the other two INSIDE a constructed artificial environment which mimics their natural one (i.e. a "dome"). I can't see them ever being able to live "undomed" on one. If you change a gas giant critter unough to live on an ice planet "undomed", it is no longer a gas giant critter but rather an ice planet critter. If you change an ice planet unough that a gas giant critter can live on it "undomed", it is no longer an ice planet but rather a gas giant planet.

The tools do not exist to model this properly in SE4 via mod for ALL the three planet types. The choice seems to be to either make each type a racial trait so you can never colonize the other, or make it work right for one and eliminate the possibility of races originating on the other two. In my data set, I did the later.

If separate abilities existed for colonizing a given planet type with a dome and colonizing without a dome, it could then be modeled correctly by making the "colonize without a dome" a racial trait and "colonize with a dome" something anybody could learn.