Some new models utilizing the "fr" suffix or prefix are still work in progress and it is likely that they might change significantly in some next patch. For this reason it is recommended that you avoid using them in your mods at this time.
When basing you model on the original ones, add to your mod also ALL original /automat/ files used by it. The names of the files are generated as SHA1 hash of theirs content so whenever we change the parameters of the material in any way, a different file will be used to store them and the original file might cease to exist if there is no other model utilizing the original parameters.
When modifying original models, always include ALL compoments of the model (pmg+pmd) instead of just those you changed. Otherwise you risk crash if we change the model.
As always when adding new objects to files which support multi-file approach (e.g. road_look.sii) it is HIGHLY RECOMMENDED to use suffix or prefix in the name to avoid conflicts with new objects we are adding in patches. Otherwise you might have to use the batch renaming functionality (see Batch renaming) to fix the conflicts when new patch appears.
Misc useful commands
Running the game with -unlimitedlog command line parameter will disable the standard 1MB limit on size of game log file. This might be useful during update if you want to focus on some bugs first.
Running the game with -validate command line parameter or executing validate command on the console will run special game mode which will load all defined models, prefabs, vehicles and other objects to detect missing textures and similar errors. By examining the game log you can determine what the game was trying to do when error appeared. Note that there is still lot of things which might be wrong which are not checked in this mode.
Running the game with -error_overlay command line parameter will show overlay with number of error and warning messages printed to the log once at least one such message is printed.
How to convert map
If your mod overrides signs.sii or sign.dlc_north.sii, you need to update those files to account for us moving some signs from DLC Scandinavia to base.
Convert AI model storage definitions to the new format
Convert the road look definitions to the new format.
Convert the speed limit and license plate definitions in country data to the new format.
AI vehicle model storage
For each supported vehicle type (currently: car, truck, bus) a separate unit exists in /def/vehicle/traffic_vehicle_type.sii. These units contain paths to actual model storage for given vehicle type (e.g. /def/vehicle/traffic_storage_car.sii)
AI trailer model storage
For each supported trailer type (currently: semi_trailer) a separate unit exists in /def/vehicle/traffic_trailer_type.sii. These units contain paths to actual model storage for given trailer type (e.g. /def/vehicle/traffic_storage_semi_trailer.sii)
AI vehicle definition
Property attachable is now obsolete. It has been replaced by an array attribute attachable_trailer. The array contains unit names (as strings) of all trailer models which can be attached to the given vehicle.
To allow all trailer models, add an empty string at the beginning of the array:
AI trailer definition
To allow future features and improvements, the type of the unit defining an AI trailer CHANGED FROMtrailerTOtraffic_trailer
trailer : traffic.trailer.fuel_cisternchanges totrafic_trailer : traffic.trailer.fuel_cistern
Road look definition
The lane_count_left, lane_count_right and ai_speed_type attributes are now obsolete. They were replaced by lanes_left and lanes_right arrays. (The array items are ordered from the center of the road to the borders) This allows specifying some traffic lane attributes for each lane separately - see "Traffic lane definition"
Traffic lane definition
Traffic lane definitions can be found in /def/world/traffic_lane.sii.
License plate definition
The definitions of per-country license plates were moved into separate /def/country/<country_name>/license_plates.sii file. It contains separate unit for each vehicle type (car, truck, bus). If more than one unit exists for some type, the game will use the first unit it encounters.
Country speed limit definition
The definitions of per-country speed limits were moved into separate /def/country/<country_name>/speed_limits.sii file. It contains separate unit for each vehicle type (car, truck, bus). If more than one unit exists for some type, the game will use the first unit it encounters.
Separate interior model
The cabin interior now uses separate model for rendering from external views. That model is defined using new ext_model, ext_variant and ext_look attributes of interior accessory.
The toolbar window and editor window were combined into one.
Editor window can be resized, docked, maximized.
Resolution can be choosed from menu View > Resolution.
Mouse cursor behaves significantly better.
Free camera can be rotated with right mouse button (RMB).
Several items can be combined into one by "Ctrl+G" or from menu Tools > Compound Selection.
3D move manipulator
Editor contains 3D move manipulator ("gizmo").
Move manipulator can lock movement along one axis when X, Y or Z pressed.
Move manipulator can lock movement along one plane when Shift+X, Shift+Y or Shift+Z pressed.
Eg. Shift+Y means that movement does not change in Y axis.
Editor can render grid when enabled from menu View > Grid.
On toolbar you can enable/disable Snap to grid and Snap to nodes.
Beware: Grid is placed in zero height, if you have items in different height, the snapping may seem weird as it is distorted by perspective.