I'm a beginner on U3D and game engines in general. Here's some of the things learned so far; feel free to critique, correct or illuminate.
First off, read through the obvious sections of the manual to familiarize yourself with U3D's GUI and navigation methods.. It's pretty easy to use. The manual can be viewed in 'Manual' or 'Reference' mode. For the first round of familiarization, I skimmed through the whole thing in the 'Manual' mode so the programmer could present the product to me in what they considered the logical order. I always give the creator the benefit of the doubt and let him or her give me their preferred presentation, first.
So... you should be able to navigate in the 'Scene' view, understand what it means when you go to the 'Game' view, know what the screen mode buttons do, etc.
In the manual, read the FAQ section. It's two thirds of the way down in the table of contents. THAT section will allow you to actually create something to play with quite quickly. Take a look at the 'How to make a simple first person walkthrough' under 'Game Code Questions'. That right there gets most of us to the exact thing we're looking for!
Read the section on the Terrain Editor. That's key, of course. HOWEVER.. if your AC model has a reasonably sized piece of earth modeled, your camera character will be able to 'walk' on it... although it'll also be able to fall off the edge. I've had best results by editing a U3D terrain to fit my site model, then turning off the site mesh. This also allows full utilization of u3D's rather awesome site entourage features like animated trees, grass, etc.
Do the 'Skybox'... you'll want that!
Explore the lighting sections... you'll need that, too. Use a 'Directional Light' as your Sun. Read the lighting section to learn how to Transform (edit position, rotation) and set the parameters. My sun has an intensity of .6 and is =almost= pure white, with a very slight yellow cast. It's also set to 'Hard Shadows'. Never mind the warning about 'Real Time Shadows'... you don't need them for a static Sun position. If you want to run a light study along with the walk through, you'll need the real time shadows offered in the Pro version. For the Free users, we'll Lightmap instead, which calculates shadows once and saves them as an image used for shadow mapping (more on that later). NOTE.. you won't see cast shadows until you've done the Lightmapping process, known as 'Baking'. You will see the ambient and diffuse effects, though.
If you're conversant in Java script, you'll be able to make this software get up and dance with the stars, within hours, as pretty much everything is done by scripting. Looks like I'll be learning how to write Java! That said, there's a bunch of predefined scripts that allow the non-Java speaker to get results, so there's time to sort out one's language capabilities.
Importing Meshes from external software:
Save AC models as 3DS files. If the model is large, save it in pieces sorted in categories that suit your personal logic for model organization. For instance, my own layering system is categorized by trade, so when I write my 3DS files, they'll appear in the OS file manager like so:
HOUSE_CABS.3ds
HOUSE_FNDN.3ds
HOUSE_MECH.3ds
HOUSE_MLDG.3ds
HOUSE_PLMB.3ds
HOUSE_ROOF.3ds
HOUSE_WALL.3ds
In the above example 'HOUSE' would be the job name or number.
There's two reasons for 'breaking up' the AC model. First, U3D doesn't like large meshes. Two, it allows us to have more control over individual elements and allows us to turn stuff on and off like we're used to in our BIM software. You don't eat a whole steak in one bite.
Each of these files are considered 'Meshes' by U3D, and represent discrete 'Assets' in it's 'Project' window. If you saved the files out of AC 'by material', then these meshes will actually be composed of several 'Child' meshes; one for each material, which can be discretely selected and manipulated in U3D.
Once the meshes have been imported into the 'Project', they can be dragged into the 'Hierarchy' window, and you'll see them appear in the Scene (hopefully, if they're in view.. if not, read the U3D manual to learn how to zoom to a selection).
When selected in the Hierarchy window, you can scale a Mesh with the controls in the Inspector window, where you will be editing that instance of the mesh in the scene. The source mesh Asset will remain un-altered until you rewrite it from AC.. it's hard to 'destroy' or mess something up, so experiment.
Model origin: I'm personally very disciplined this way. My AC models are always located in space with the entire site modeled and tucked tightly into 0,0 on the 'X' and 'Y' axes, and all in the positive quadrant of space. The 'Z' of all model elements are placed relative to true sea level, where sea level is z=0. That's me. This means that when I save the 3DS files, they show up in U3D in the same place relative to it's coordinate system. NOTE.. the gamers look at the universe a little differently than we do. Our 'Z' axis is 'Y' in their world, so yes.. the coordinate system in U3D is 'goofy' by our standard.
Model Scaling: This is done by adjusting the Transform settings of your meshes when selected in the 'Hierarchy' window. On my first projects, I had scaled my meshes by a factor of '1', i.e. unchanged from the original import. It appears that this maintains 'real world' dimensions in U3D where everything is expressed in metric. My kinetic elements (like the camera character) worked properly. The only problem was with the terrain elements - I couldn't get tight enough resolution in the modeling of the terrain to build up behind retaining walls, cut divots for pools, etc. By scaling the model up 10 times, I was able to remedy the terrain resolution issue, but it does screw up the physics and tree sizes a little bit. I'm trying to work out a solution for that. Here's what I WANT - to import the model at 1X scale, and have the smallest terrain brush be under 500cm. To get a 'finer' brush, the only option is to scale the model rather large. Rescaling the trees was easy.. simply select their meshes and adjust the Transform parameters to suit your model scale. Those are found in the 'Trees' folder of the 'Terrain Assets' folder in the 'Project' window - select the tree mesh and adjust it's 'Scale Factor' in the importer window of the inspector. That will adjust it's default size, then you can scale it in a range in the Terrain Editor.
The model elements can be moved around in space numerically in the inspector or by dragging in the Scene view. For myself, I find it easy to move stuff in the scene intuitively, then fine tune the final setting to 'even numbers' in the inspector (I like even numbers.. I'm a little psychotic that way).
Mesh Import Settings: NOTE... this is fully editable in U3D and has no external effect on your 3DS files written from AC, or, as the graphic artists would say it's 'non-destructive'. These settings are accessed by selecting the meshes in the 'Project' window (NOT the Hierarchy window). The '(Mesh 3DSImporter)' window of the inspector has lots of settings which I can't fully explain here - you'll need to hit the books and forums for that. However, one of particular note is the 'Generate Lightmap UVs' button. In order to facilitate lightmapping, you'll need to check that button. Doing so adjusts the meshes' UV's to be lightmapped within U3D. If there's any corruption of meshes in your AC model, it will crash the importer when this box is checked. This creates no immediate catastrophe, but will in turn crash the lightmapping engine later. In my case, I had some cabinets that had corrupted prisms that AC didn't fret about, but this software did. From now on, I'm going to be more careful with my GDL parameters on my cabinets. For the purposes of moving ahead, I simply unchecked Generate UVs for those meshes, and then skipped selecting them when doing the lightmapping process. This won't always be an option, so making sure I can get clean UV's in U3D is added to my mental checklist of modeling tasks from here on. For those using other 3D software, like 3DS or Blender, it might by worthwhile to pass through one of those programs to set up UVs in advance, which will allow you to put that worry aside while working in AC. On a complex model, Applying the UV generation can take some time and all your machine's fans will run hard!
Lightmapping: This will get you static shadows. It takes a while for the lightmapper to work - be patient. Your machine will sound like it's processing a mission to Mars. You can include as many lights as you want, and include or exclude meshes by selection in the Hierarchy window. I found it best to make a project with some simple shapes and basic terrain to learn how to use the lightmapper.. so it's fast to make changes and test it's settings. It's a bit of an Art / Science thing to learn.
As stated previously, this software has a 'depth' about equal to AC itself, so I'll still be learning new tricks months or years from now. Also, it appears to have a robust update schedule and an active, enthusiastic community. I encourage you to explore the forum on their site.. There's a few of us Architorturists in there, and they're often exploring solutions to issues we all have in mind. I'll try to watch the forum here to for new input from the group, as well as answer any questions I can. Hope this bit helped.
I've updated the finished builds posted earlier with better lighting. I added a directional 'back light' for better ambient light on the whole site (no shadow casting) and a point light (with soft shadows) in the Living Room to give some definition to the interior surfaces. Worked real good. Did get an increase in demand on machine resources, though. Here's those links again, one for PC, one for MAC:
http://www.dmsdesign.us/planrm/CHIOU_2011-08-17.zip
http://www.dmsdesign.us/planrm/CHIOU_2011-08-17_MAC.zip
Talk soon!