Soldier variation

Normally every soldier in a unit uses the same model, so a forty-man unit is forty copies of the same guy. This feature changes that in two ways: a unit can mix several models, picked at random for each soldier, and the model can change as the unit’s armour is upgraded. Both work in RTW and M2TW.

The old soldier line in export_descr_unit.txt still works exactly as before:

soldier  roman_legionary  40  0  1.0

The model on the soldier line plays two roles. It picks the mesh rendered in battle, and it tells the engine which skeleton drives the unit - how fast it walks and runs, where missile fire spawns from, whether the primary weapon has a charge animation. If you add armour_ug_models (below), the per-tier entries swap the mesh; the skeleton stays as whatever was on the soldier line. So you can name one model on the soldier line for the skeleton and entirely different models in armour_ug_models for the meshes, if you have a reason to. Vanilla M2 did this for a handful of units.

The new soldiers block (note the s) lists several models, and each soldier in the unit is randomly given one of them:

soldiers  40, 0, 1.0
{
    skeleton  roman_legionary
    default
    {
        roman_legionary
        roman_legionary_var2
        roman_legionary_var3
    }
}

The numbers after soldiers mean the same as on the old line: count, extras, then optional mass, radius and height. Inside the block, default is the pool of models an un-upgraded unit draws from.

skeleton is required when you use the soldiers block. It names the model whose skeleton drives the unit — the same role the model on the old soldier line plays. The named model has to exist in battle_models.modeldb, but it does not have to appear in any of the mesh pools below; if you want a skeleton-only model that never gets rendered, that’s fine. If the keyword is missing or the named model can’t be found, the parser fails the unit loudly.

Armour upgrades

Add armour N blocks to swap the model pool when the unit’s armour is upgraded:

soldiers  40, 0, 1.0
{
    skeleton  legionary
    default  { legionary_a0_v1  legionary_a0_v2 }
    armour 1 { legionary_a1_v1  legionary_a1_v2 }
    armour 2 { legionary_a2_v1  legionary_a2_v2 }
}

A unit draws from the pool whose number matches its current armour upgrade level: no upgrades uses default, one upgrade uses armour 1, two uses armour 2. The pools are independent, so they don’t need matching counts. default can list four models and armour 2 just one.

There is also a shorter form, one model per tier and no per-soldier variation:

soldier           legionary  40  0  1.0
armour_ug_levels  0 1 2
armour_ug_models  legionary  legionary_a1  legionary_a2

The soldier line still drives the skeleton; armour_ug_models just swaps the mesh per tier. M2 has had this form for a long time; it now works in RTW too.

A few things to know:

• The soldiers block replaces the old soldier line, so don’t also give the unit a soldier line or armour_ug_* lines. The parser reads whichever form comes first and chokes on the leftovers.
• Every mesh in the unit (the default pool and every armour N pool, or the meshes listed in armour_ug_models) needs to be rigged to the same skeleton as the model named on skeleton / soldier. If a mesh uses a different bone layout, its animation comes out garbled. The model itself can differ, it’s the bone layout that has to match.
• M2 already varies soldiers within a single model through mesh variations. The soldiers block does something different: it swaps the whole model. The two stack, so the block picks which model a soldier uses and mesh variations then vary that model further.

Mounts and animals can vary the same way; see Mount and animal variation.