Of the many aspects of editing the (land and aircraft) equipment file, the defense factor [DF] is a quantity with potential to be confusing. The confusion is driven by two things. One of these is that, internally, TOAW uses defense strengths, and not factors, in strength calculations. The other confusing item is that while the game autogenerates defense strengths for certain types of equipment, in other cases it appears to more or less accept the DF value as shown in the equipment file.
Before this is further discussed, let us consider a statement by JAMiaM considering DF.
The defense factor is a number that, for the vast majority of equipment types, is scaled from 1-10 and represents a rough ability of that equipment to absorb firepower without being destroyed. Equipment is defined here, as items within the database, whether they are multi-man items like squads and teams, or singleton items like AFV's, and Guns, which also may be multi-man operated. Thus, you have guns which will be inoperable after a single direct hit having a DF of 1, unarmored vehicles with DF's of 1-2, untrained squads about 3-4, AFV's between 5-8, and trained infantry squads with DF's of 10.
Some airframes, most notably more modern pieces, and ships are the exception to this general rule, and scale higher.
Without getting into specific formulae used by TOAW to autogenerate defense strength, anyone editing the equipment file should know which kinds of equipment have an autogenerated defense strength in order to minimize confusion, and, perhaps, time spent researching equipment characteristics. These equipment items in TOAW are given an autogenerated defense strength:
* Any armored vehicle (as set in FLAG0 for the equipment; simply giving an armor rating will not make equipment armored in game terms)
* Any gun, mortar, rocket, or missile capable of ranged anti-personnel fire - this includes such mounted on vehicles
Other kinds of equipment, including aircraft, have (apparently) a defense strength that is equal to the DF entered in the equipment file.
While we cannot change the autogenerated defense strength for certain equipment items, those values have to be considered when we assign a DF for the other equipment -- in order to maintain a consistent approach to the modeling of items in the equipment file. Whether we agree with the autogenerated values or not is largely irrelevant; they exist and have to be kept in mind. With this thought out front, anyone modifying the equipment file may wish to be aware of the range of values that are autogenerated by TOAW.
As best as I can determine, the autogenerated defense strength can range from 1 to 15 (but see comment for armored equipment below). This range is not fully present in any given equipment item. The ranges for equipment categories are:
: 10 to 15 for railway guns, ASMs, and fixed guns
: 1 to 6 for non-armored vehicles capable of ranged anti-personnel fire
: 5 to 10 for for armored vehicles capable of ranged anti-personnel fire*
: 5 to 11 for armored equipment employing direct fire (tanks etc.)*
: 1 to 6 for towed artillery, mortars, and multiple rocket launchers
* - the values for armored equipment may range higher than 11 (very much higher) depending on how much armor the equipment has.
Those modifying the equipment file, before making any changes, will have to have an idea of how their assigned DF values will function in tandem with the autogenerated defense strengths of the game. An example in the default equipment file of how this can be gotten wrong can be seen in the definitions for the PATRIOT SPSAM, and its near-clones, the Improved PATRIOT and the Barak SPSAM. These systems were assigned a DF of 12 -- that is to say, using JAMiaM's definition above, a single SPSAM of this sort can absorb more punishment than a rifle squad before being destroyed. This DF assignment becomes even more curious when one looks at a photograph of the MIM-104 PATRIOT; it is four missile launch tubes mounted on a tractor-trailer.
And this is not just a cosmetic error. If I understand the comments in the TOAW log file correctly, when overrun (retreat before combat) attacks are executed, TOAW calculates the strength of both sides ... and defense strengths, even of passive defenders, are counted in the calculation. So while the PATRIOT SPSAM cannot directly attack ground units with anti-personnel or antitank fire, it can contribute to overrun actions by virtue of its inflated DF. Any soft vehicle with a SAM should probably have a DF of 1, as is the case for the definitions of the Taiwanese Tien Kung SPSAMs: these kinds of vehicles just are not ground-takers or -holders.
All that noted, I have to point out I have no idea how the DF's for aircraft and helicopters are assigned (these are not autogenerated). They increase as the equipment becomes more modern and capable, but that is all I can determine. I would appreciate hearing from others how they interpret aircraft equipment characteristics to come up with a DF that works within the TOAW system.