Disguise

Infantry Disguises (RA2 & YR)

You noticed how the spy can disguise itself as an enemy infantry and walk right past the defenses (except dogs/yuri)? To achieve that, you need only a couple of tags and a special weapon. Firstly, add CanDisguise=yes and PermaDisguise=yes to the soldier's code. Then, make sure the unit's anti-infantry weapon has a warhead with MakesDisguise=yes set.

Now how do you make other units detect disguised units? Easy, by adding DetectDisguise=yes to their code.

Vehicle Disguises (RA2 & YR)

The only disguising vehicle in the unmodded game is the Mirage Tank. This kind of disguise requires CanDisguise=yes, but not PermaDisguise=yes. Also, the vehicle that uses it should not have a turret or a barrel as the disguising logic can't turn several voxels into a single shp, so it'll end up with multiple trees - one for vehicle body, drawn at ground level, one for turret, drawn on top of the first one, and optionally one for barrel. If you want to let vehicles pick their own disguises, you once again need a warhead with MakesDisguise=yes, but since the Mirage Tank uses terrain objects instead of infantry as disguise, you will also want to add TerrainFire=yes to the weapon, which makes the vehicle able to target trees and other terrain objects without having to use force-fire.

AlliedDisguise, SovietDisguise, and ThirdDisguise (YR only) tags define which infantry the units with PermaDisguise=yes look as when the owner hasn't disguised them yet, for each side respectively.

DefaultMirageDisguises defines a list of terrain objects that a CanDisguise=yes unit without PermaDisguise=yes will try to look like when it doesn't have a custom disguise.

So if you give a vehicle PermaDisguise=yes, it will look stupid - it will use the Allied/Soviet/ThirdDisguise instead of DefaultMirageDisguises, end up looking like an infantry, and because SHP vehicles (SHP is the only way infantry can look like) use a different method to reference proper art frames, you'll see a GI with his gun spinning around as the tank moves (the game then sets WalkFrames=1 and uses the first frames of the infantry SHP as it's walking animation).