Is there any way to use the CK to design new building architecture rather than being stuck with the vanilla game's designs?

You would need 3rd party software to actually create the textures and things.

I use GIMP for lighter stuff but more advanced users would want a 3d program.

There's some highly talented peeps on these forums .... I hope they chime in with what they use cause I'd like to know myself

When thinking about designing my own castle I always think back to the fantasy like Camelot from one of my favourite movies, Excalibur, where Camelot was a castle made of silver and gold rather than being a conventional fortress. In Skyrim's case I've envisioned a castle and even city that looks like it's made of Dragonbone! Or there's a villain's fortress that could have a Daedric design. I just much prefer more thematic fantasy designs to a RPG than simply having only conventional looking buildings. Historical looking buildings are all well and good, but I do like the idea of adding the magical high fantasy look to some locations.

Here is my mod as an example of a custom building: http://skyrim.nexusmods.com/downloads/file.php?id=12033

As far as I've seen, I'm generally 'leading the pack' on new architecture, but I'm afraid I come with bad news. Currently, we have no way of creating proper collision geometry, so anything you make must either match the shape of an existing item, use a series of convex hulls for collision (and still not quite work right) or have no collision, so you'd just use blocks in CK to keep the player from passing through your new stuff.

In order to make new architecture, you'll need Blender or 3D Studio Max (Free 2 year license for students), Nifskope, Niftools for your 3D program, and Gimp / Photoshop for texturing. I highly encourage you to jump into 3D modeling, but you should know it isn't something you learn in a day. I've been at it for 15 years and I'm still learning.

And here is a whole village made of new architecture meshes, with collision using the above workarounds. http://www.moddb.com/mods/skyrim-warring-states/images

Observe, what did you end up doing for your collision problem? I remember seeing your model come up when I was googling around for answers.

Considering the shape of my house, constructing Collision boxes in CK worked well in my case. Using Convex and other shapes from 3DS Max was/is too imprecise for my purposes. This is too bad, because it precludes (or at least complicates) many different shapes that might otherwise be feasible.

That 3D Studio looks pretty handy and something I'd be very interested in getting. But I was thinking about using the original building structures, especially those of the castles, and retexturing them to look like they're made of dragonbone, with maybe some dragonbone greeblies added for walls, battlements etc. I mean, from what I can see every castle type structure you'll ever need is already in the game. I'm guessing all you really need to do is do what I see a lot of modders do with costumes, weapons and characters only on a much larger scale.

BTW. I might be able to get hold of the 2011 version of 3D Studio on the cheap. Is that worth getting?

I always wondered how it would be possible to import new architectures. Because I already thought that it wasn't possible for Skyrim itself to "see" the walls and make collisions. So you have to do everything with collision boxes instead , right?

Modern games generally use some sort of "collision primitive". This is so the engine doesn't have to worry about calculating collision based on the polygon complexity we see visually and as complex objects move around in the 3d game world.

The Creation Kit provides collision primitives (cube, sphere) that we can "wrap around" object meshes in the Creation Kit. Skyrim also uses more complex collision meshes, but unfortunately Bethesda doesn't give us the tools to work with those. Ideally, we could create our collision meshes inside 3DS Max (or some other 3D design application having a plugin or conversion to .nif). The trouble is, the existing plugins (NifTools) are not sufficiently compatible with Skyrim to be usable in most cases (those requiring new collision mesh)

This means that externally creating new architectural models for Skyrim is severely hampered by inadequacy (read broken) of the existing plugins for 3D design programs, and the very limited CK functionality (cube and sphere).

I don't see many new models going into Skyrim until someone fixes NifTools plugins and I don't see that happening until someone figures out the new Skyrim collision mesh formats (or Bethesda releases the information). This problem (lack of ability to create complex collision meshes) has effectively killed 3D modeling opportunities that might otherwise have existed for this game.

Other than a handful of new designs (like mine and a few others) and new models using existing collision meshes, Skyrim modding is pretty much relegated to new spells, effects, etc., and re-arranging (copying) existing architectural (and other objects).

Agree the above. I have tried the basics of new architecture and its a waste of time trying to get the current max and nif tools to produce a fully fledged custom building with collision. Everything now hinges upon nifskope and max plugins.

TheKarithian have you tried the tutorials from saidenstorm? He claims that his tutorial do work for skyrim to get collisions... I haven't tried tough so I couln't test....

I've not seen the tutorials you speak of. Granted, most of my intensive work on this issue was done shortly after game release, but to my knowledge, no fixes have been made available, and no tutorial is going to solve the problem.

Yes, you can get collision meshes out of 3DS Max (and perhaps Blender also), and with some "tricks" you can export from NifSkope. From there (NifSkope) you can export into Skyrim compatible .nif models. The trouble is, no matter what you do, the colllision meshes derived from NifTools simply don't work very well (not precise enough) in many cases.

Take Convex Shape mesh for example. It would be nice if that actually worked properly. Even better if we could use "Strips Shape" at least, but that's currently a no-go too.

Here is a crashed "space pod" model I tried to use Convex Shape collision mesh: http://www.x3dmod.com/ftp/images/skyrim58_wreck2.jpg

As you can see, the shape of that model does not lend itself well to box or sphere collision (from within CK) and it's impossible to get any NifTools-based meshes that fit the exterior shape accurately enough for my purpose - and that's not even talking about being able to crawl inside the pod.

There have been plenty of rumors about people claiming to import collision meshes, but it simply doesn't work in any real sense and the fact is we are not seeing many people publishing mods derived from alleged results. Yes, you can export a Convex Shape mesh from 3DS and you can get it into the game, but it's almost worthless because the shape usually doesn't fit the model mesh properly (no matter how many times you trial and error the mesh size).

Having said all the above, you can still get good collision meshes if you can apply some combination of box and sphere shapes within CK. As mentioned earlier, this method works well In case of my Dovahkiin Sanctuary (yellow is CK Collision boxes): http://www.x3dmod.com/ftp/images/skyrim_collisionmesh1.jpg

Part of the reason I am detailing all this, is because I would love someone to point out a real workable alternative, but unfortunately, I seriously doubt that's going to happen until the tools are fixed.

This (Collision) problem, along with the Navmesh bug, are the two main big fails for Skyrim modeling/modding (imo). There is faint hope (based on statements from Bethesda) the Navmesh bug will eventually be fixed, but I'm not holding my breath and I have more or less given up on Collision ever working properly with this game.

Well as long as the developers stay dump on the modders sugestions there won't be much to do I guess... they seem just seeing the surface shiny new retextures and rehakced stuff armors and they may be think that it's all fine and the complains are just from a small number of whiners...