Steamroller Arma 3 Road Converter

ianbanks |

Steamroller automatically converts Arma 2 road networks to shapefiles for use with Arma 3’s new road technology. It was originally written in 2014, and has since been used by the authors of many popular Arma 2 maps to update their road networks for Arma 3 map releases.

You can download it from here:

Download "Steamroller (Release 3)".

Using Steamroller

Steamroller works by:

Reading the text job (.job) file specified on the command line. The download for Steamroller includes an example job file that will work for most of Bohemia Interactive’s Arma 2 (CA) maps.
Loading an 8WVR (unbinarized) format .wrp. The source .wrp file is specified in the configuration:
```
source "C:\\Working\\CA\\Chernarus\\chernarus.wrp"
```
Note that in configurations, backspaces must be escaped.

If the unbinarized .wrp file is not available, any binarized .wrp can be converted to 8WVR using Mikero’s tools.
The objects in the map are filtered by comparing the .pbo path of each object against a list of prefixes. One or more prefixes sections in the configuration supply the list of prefixes:
```
prefixes
{
    include "ca\\roads_e\\roads"
    include "ca\\roads_pmc"
    include "ca\\roads2"
}
```
The generated log file (placed in the destination directory) includes a list of .pbo path directories that were excluded by the filter. All .p3d files in these directories will be ignored for the process of building roads:
```
Objects from the following directories were ignored:
  ca\buildings
  ca\buildings2\a_advertisingcolumn
  ca\buildings2\a_citysign
  ...
```
The filter is designed to increase the speed of road generation. Including directories that do not contain roads is harmless, but will increase the time required to generate shapefiles.
One or more search_path directories are then used to locate the .p3d files corresponding with road pieces. Multiple paths can be specified in the configuration:
```
search_path "P:\\"
search_path "C:\\Working\\Map_Objects"
```
If any .p3d path aliases have been specified in the configuration, they are applied to the paths of the filtered .p3d files:
```
aliases
{
    "ibr\\ibr_rn\\s10 100.p3d" "ca\\roads2\\asf1_10 100.p3d"
    "ibr\\ibr_rn\\s10 25.p3d" "ca\\roads2\\asf1_10 25.p3d"
}
```
Again, backslashes must be quoted.

This feature is only needed when copy of the original road model is not available, and where a road model with identical memory points is available. Most custom roads were designed to be exactly the same dimensions as the Arma 2 (CA) roads, and therefore most maps with custom road pieces can be converted by adding the Arma 2 samples to the search path and adding aliases to the samples.
For each .p3d file found in the map and in a search_path directory, the model is loaded and checked for the following road memory point:
- "LB", "PB", "LE" and "PE", and, for intersections,
- "LD", "LH", "PH" and "PD".
Any .p3d files that are found in the included directories that are not roads are also reported in the log file:
```
The following models do not have any road memory points and were ignored:
  ca\roads2\dam\dam_barrier_40\dam_barrier_40.p3d
  ca\roads2\dam\dam_conc\dam_conc_20.p3d
  ca\roads2\dam\dam_conc\dam_concp_20.p3d
```
These models are ignored for the purpose of generating the shapefile.
The models are placed into layers (or deleted) using regular expression rules. There are three different types of rules, all of which use regular expressions to match the .pbo paths of the .p3d model files.
- layer rules place road segments into a specific layer. For example:
```
layer "asf1"
{
    include "^ca\\\\roads2\\\\asf1_"
}

layer "asf2"
{
    include "^ca\\\\roads2\\\\asf2_"
    include "^ca\\\\roads_e\\\\roads\\\\asf2_"
}
```
  Any segments that match a layer rule are placed into the layer in a shapefile.
- glue rules are used for intersections that are connected to one or more regular layered segments:
- remove rules are to delete segments that shouldn’t be converted. Typically these will be bridge segments or other non-flat models that are not appropriate for use in Arma 3 road files:
```
remove
{
    include "^e76_roads\\\\(betonblock|bridge1|channel)\\\\"
}
```
Once road models are loaded and assigned to layers, the memory points of each road segment instance are placed into a spatial index and then "snapped" to adjacent road segments. The memory points don’t need to be exactly aligned; a threshold (the snap_threshold) is used to determine how close points must be.

The default value for snap_threshold can be changed in the configuration:
```
snap_threshold 1.5
```
Road segments that snap are joined into continuous shapefile roads based on layer assignments. Any glue segments are assigned to the roads that connect to them (for example, in a "T" junction, part of the junction is assigned to the through road, and the other part is assigned to the branching road.
Any coincident points from road centrelines are removed. The threshold for coincident points is coincident_point_threshold, which is the minimum distance between points in meters.
The shapefile roads are then simplified using Douglas-Peucker simplification. The level of simplification is set by:
```
simplification_threshold 0.5
```
The simplification guarantees that for any simplified line segment in the output road, the points of the original road fall no more than simplification_threshold meters from the simplified road centerline.

Having the simplification threshold too small will cause many small segments to be generated which will result in visual artefacts in game. Roads are smoothed by the game using curve fitting, so only a few segments even on highly curved roads are required.
The shapefiles and a log are written out. The files are written to a directory specified by:
```
destination "C:\\Working\\Steamroller Output\\"
```
The file names are based on the source .wrp name, and includes:
- A .shp file, a shapefile.
- A .dbf file, an attribute file.
- A .log file, a text log of the diagnostic output.

Conversion Examples

After conversion, the shapefiles can be loaded into Terrain Builder or a GIS package and viewed and edited.

This is an example of Chernarus’ roads after conversion, with each of the layers shown in a different colour:

And this is an example of Takistan’s roads after conversion:

Note that any shapefiles or other data derived from materials released under Bohemia Interactive’s Public Data licences would also almost certainly be subject to the same licence conditions.

Example Configuration

The following is an example job file for upgrading Chernarus roads:

search_path "P:\\"

snap_threshold 1.1
simplification_threshold 0.5
coincident_point_threshold 1.1

source "P:\\CA\\Chernarus\\chernarus.wrp"
destination "P:\\new\\new_chernarus\\data\\"

#include "ca.jobinclude"

To specify the shapefile layers that roads should be placed on, the following ca.jobinclude file is referenced in the above job file:

prefixes
{
    include "ca\\roads_e\\roads"
    include "ca\\roads_pmc"
    include "ca\\roads2"
}

glue
{
    include "^ca\\\\roads2\\\\kr_"
    include "^ca\\\\roads_e\\\\roads\\\\kr_"
}

layer "runway"
{
    include "^ca\\\\roads2\\\\runway_"
}

layer "invisible"
{
    include "^ca\\\\roads2\\\\road_invisible"
    include "^ca\\\\roads_e\\\\roads\\\\road_invisible"
}

layer "asf1"
{
    include "^ca\\\\roads2\\\\asf1_"
}

layer "asf2"
{
    include "^ca\\\\roads2\\\\asf2_"
    include "^ca\\\\roads_e\\\\roads\\\\asf2_"
}

layer "asf3"
{
    include "^ca\\\\roads2\\\\asf3_"
}

layer "city"
{
    include "^ca\\\\roads2\\\\city_"
}

layer "grav"
{
    include "^ca\\\\roads2\\\\grav_"
}

layer "mud"
{
    include "^ca\\\\roads2\\\\mud_"
}

layer "path"
{
    include "^ca\\\\roads2\\\\path_"
    include "^ca\\\\roads_e\\\\roads\\\\path_"
}

layer "bridge"
{
    include "^ca\\\\roads2\\\\bridge\\\\"
}

layer "asf10"
{
    include "^ca\\\\roads_e\\\\roads\\\\asf10_w10_"
}

layer "asf12"
{
    include "^ca\\\\roads_e\\\\roads\\\\asf12_w12_"
}

layer "dirt12"
{
    include "^ca\\\\roads_e\\\\roads\\\\dirt10_w10_"
}

layer "dirt7"
{
    include "^ca\\\\roads_e\\\\roads\\\\dirt7_w7_"
}

layer "dirt2"
{
    include "^ca\\\\roads_e\\\\roads\\\\dirt2"
}

layer "dirtrunway"
{
    include "^ca\\\\roads2\\\\runwayold_80_dirt"
}