Actors are the graphical representations of objects in the game. They combine meshes, textures, animations and props, and also control some other graphical features (such as whether the objects casts shadows or has transparent textures).

Actor data is stored in XML files, which can be edited by hand, but usually the Actor Editor is used instead.

Randomness

To allow some visual variety between otherwise-identical units, actors can contain 'random' elements. (They are not strictly random - a designer can choose a particular variation of the actor.)

Example of actor data To achieve this, the actor is split into a set of groups, each of which contains several variants. See the image for an example - each row represents a variant, and groups are separated by empty lines. The second group controls helmets; when creating a unit, one of the variants ('Helmet A' or 'Helmet B') will be chosen at random, and so the unit will have either 'Advanced Helmet A' or 'Advanced Helmet B' for its 'helmet' prop. The first group has a single variant called 'base'. Since it's the only variant in that group, it will always be chosen, and so its data will always be used for that actor.

The frequency of each variant controls how likely it is to be chosen - in the example, 'Head A' will be chosen about twice as often as 'Head B'. If a variant's frequency is set to 0, it will never be chosen by the randomiser. A zero-frequency variant can still be selected by the game - for example, actors could have 'Summer' and 'Winter' variants, with the default always being Summer, and then the game could change the whole world to Winter.

Terminology

Mainly to help me understand myself:

• Variant: a named collection of data items, specifying the actor's texture, animations, etc (or any subset of those data). Shown in the Actor Editor as a single row.
• Group: a set of variants; represented in the Actor Editor by a block of rows, separated from other groups by blank rows.
• Choice: a variant from a group, which has been chosen to be used on the actor. Choices are often made randomly, and combine to form:
• Variation: a set of choices, one from each group, making up a particular version of the actor.
• Selection: a text string that usually matches a variant name; the chosen variation will use variants which match one of the selections, where possible.