[OB: ]

Overlay Behind

This is essentially the same as the [O: ] and [OT: ] modifiers except that the picture <PictureName> is placed behind the base picture, rather than instead of or in front of it.  This allows one to place a load onto a freight wagon but place it behind some parts of the base picture.  For example, one could place a load on a stake wagon and see the load behind the stakes.

If the base picture is transparent, the same effect can be obtained by using the [O: ] command in tandem with a   <D> value.

There are 3 groups of similar modifiers.

The [O: ], [OT: ], [OB: ] modifiers put the overlay picture immediately on the specified position.

The [P: ], [PT: ], [PB: ] modifiers define the place for the overlay picture (usually in a macro definition), the overlay picture will be specified in a following modifier.

The [D: ], [DT: ], [DB: ] modifiers define both the position and the overlay picture (usually in a macro definition), the overlay picture will be placed only at the usage of a following modifier, having to specify only the name of the overlaying, a single word.