You have a few different options for running CityGen. First
of all, You can create "floor plan" polygons in the FG layer, from which CityGen
will grow your buildings - even splines created with the sketch tool will
do. Or, you can have a bigger mesh (i.e. ground), and select some polygons
from it - and let CityGen do it's job on them. Or, finally, you can
run CityGen with an empty foreground layer, and it will create a random city
block for you.
When creating the floor plans, it's
almost imperative that you work in real world scale!!
After you have chosen which of the above methods you wish
to use, run the script. Depending on what you have in the FG layer, you may
be prompted with quite self-explanatory requesters (no need to go in-depth
with them here)... after those, following requester will appear.
This is the first of the four tabs in CityGen. Let's review
1. Buildings surface base name
During the building creation process, CityGen will create
various new surfaces. This string works as the base of the surface names.
Using the default "Building", you may have surfaces like Building_0001_Roof_Edge or
2. Numbered surfaces
"All (per building)"
will give numbered surfaces to each house - i.e. "Building_0003_Window_Frames"
would be the surface for the window frames in the 3rd building. "Random" will
also give numbered surfaces, but distribute them between the buildings. So,
"Building_0003_Window_Frames" can appear randomly in any of the buildings,
regardless of the order in which the buildings were created. "Off" will skip
the step which assigns these numbers to surfaces.
3. Random name limit
You can limit
the amount of numbered surfaces with this setting, in order to avoid having
potentially hundreds of separate surfaces in the model. If this setting is
set to i.e. 3, there will be three different roof, window etc. surfaces in
the model. This setting only works when numbered surfaces is set to random.
4. Per poly window names
will give different, randomly numbered surfaces to each window polygon. It's
great for i.e. having some of the windows lit in night time scenes, but there's
a drawback: Assigning the surface names can take a near-infinite amount of
time, so be cautious when using this setting.
5. Optimize original geometry
is used to avoid excess amounts of geometry, as well as ugly looking widows.
There are a few options, but usually you will get best results when this is
set to "Both". If you don't get the floorplan you want this way, experiment
with the other settings.
6. Optimize amount
is used to determine how "rough" the optimized mesh will be. In practice,
it controls the size of smallest allowed detail in X and Z axises.
7. Optimize final geometry
When this setting
is active, some simple point merging etc. optimizing will take place when
the city has been built.
8. Force positive Y axis
This will make
your buildings always grow up. If not activated, the buildings will grow to
the direction of the poly normals of the original "floor plan" polygons.
The second tab
controls the floors:
9. Floors Min / Max
created by CityGen will have a random number of floors between these two values.
If you want all buildings to have *exactly* 5 floors, set both to 5.
10. Floor height
This is, as the
label says, the height of the floors in your buildings. The +/- setting randomizes
this between buildings - within one building, the floors are always of the
11. Ground floor
will create a simple ground floor to your buildings.
12. Alternate floor
in Citygen have windows. You can use this setting to make every 2nd floor
to be either empty, or have a simple balcony.
The next tab
controls the roof appearance:
13. Roof edge
will create an edge for the roof. The randomness option can be used to have
variation between buildings.
14. Roof bevel
Use this option
to create beveled roofs. Same issues that cause problems with regular lightwave
bevels may be problematic with this setting too - i.e. concave shapes may
cause the bevel operation go cattiwompus.
15. Roof nurnies
option will create random antennae, ventilation shafts etc. to the tops of
the roofs. As the placement of these elements is controlled with the bounding
box of the roof polygon, some of the nurnies may levitate in mid air if the
house is oddly shaped (sorry ;-). Nurnie limit sets the highest number of
nurnies that may be applied to any of the rooftops.
The final tab
is used to set up the appearance of the windows.
Use this to randomize
windows between buildings, or to force all buildings to have windows.
17. Window size (% of floor height)
controls how big percentage of the building is covered with windows. Set it
to high valies for skyscrapers, low values for old factory buildings etc.
18. Inset (& of window size)
controls how deep the windows are insetted in the wall. For some modern buildings,
even a radical setting of 0 may look good...
19. Window frames
Most of the time
3D window frames tend to be the best looking. But, when you start calculating
the amount of windows in a city, you may sometimes need to reduce this setting
to keep the polycount bearable.
20. Window frame cross
Use this to apply
crossbars on the windows
21. Reset settings
Last but not
least, there's this button that's visible at all times... check it when your
cities start to look TOO futuristic (or impressionistic ;-) but you don't
know what causes the problem...
For technical help (Also for ModPak users!!), there is also
list for the PlugPak users.