I have another base object question. The SMuseleum in Solitude has a couple very visible holes in it. All that needs to be done to fix it is to shift/resize some of the components that make it. But I cannot for the life of me find the Creation Kit wiki explanation on how to move around the components of the base object. I've had reasonable success fixing simple tunnels and doorways and such, but these compound objects don't seem to be fixable.

And a bleg on the USKP list didn't find somebody else willing to do it. So it's time for me to learn.

If you need to learn how to use the construction kit, this is a good place to start:
http://tesalliance.org/forums/index.php?/forum/114-creation-kit-basics/

Thanks, I've already done the tutorials, been using the CK for several months, and can already do many/most of the things at your alternate training course there.

I was not able to find editing a base object there. That only uses pre-built objects. Anybody else able to point to posts describing editing a base object?

I guess I have no idea what you 'mean' by base objects.

If your covering holes, just plop a rock or something in the place and move it around to put it in position.

OP mean holes in the actual object, the nif file. Not holes in the landscape mate.

Yes. Although in this case, it leaves 2 holes in the landscape, as it is the landscape.

The SMuseleum in Solitude has a long skinny hole in the roof of the stair (showing a slice of sky and the walk next to the building), and another fairly large hole in the green turf next to its rock pile (showing a blackish watery stuff far below).

When I "edit" the base object, it gives me a list of sub-objects. How do I rearrange/resize them?

You need to fix the actual model. The "sub-objects" you mention are probably the different textures of that object that you can override in the CK.

Modeling can't be done in the CK. You need to extract the NIF model from the Meshes BSA and either fix it in NifSkope or import it in 3DS Max or something similar and then correctly export it again to a NIF. I'd recommend fixing it in NifSkope, it's a matter of changing the coordinates of a bunch of vertices.

Then I wish they would have labeled that list "textures", so I'd be using the correct terms, and helpers would understand me.

When I try "edit", the CK merely opens up a file menu.

I have no idea what I'm doing wrong, and haven't been able to find a tutorial or explanation. (I'll Google NifSkope, I was trying GIMP.) Obviously, I'm missing something. There's got to be an decomposition/extraction process, an edit process, and a reintegration process. But the documentation isn't very helpful. Pointers?

Things like models and textures are external resources, packaged in archives with a BSA extension. You can find them in your Skyrim/Data folder. You need to extract those archives somewhere (there are several programs to extract BSA archives) so you have direct access to the resources. Any object that has a visual 3D representation in the game always makes use of a NIF model file. It displays the model path so in the panel when you "edit" an object. You can also change the path of the model that is used for that object, and you can override the default texture paths for that model (the default ones are defined inside the NIF file itself).

In your case you shouldn't change anything about the object in the CK at all, just find the corresponding NIF file, fix it, and add it to your mod upload and it will override the vanilla broken one.

As I said before, if you wish to fill the 'holes' using the CK, you have to place another object in the hole to fill it. A rock, a flat wall piece, anything. You cannot edit a mesh file in the CK, all you can do is attach different textures to existing meshes.

Otherwise you have to edit the meshes (called a NIF file) which is not easy to do using Nifskope or use a 3D modeling program.