[O: ]

Overlay

Overlays the picture <PictureName> on a base picture at the coordinates <X>, <Y>. The number of pixels specified in <D> are cropped from the bottom of the overlay picture, thus enabling one to "push" the overlay picture down. The default for <X> places the middle of the overlay picture at the middle of the base picture and the default for <Y> places the overlay picture on the top edge of the base picture.  The default for <D> is 0.

This command  can be used to place loads, logos and other such modifiers onto vehicles.  The <D> parameter is used when, for example, a load "floats" over a freight  wagon because the wagon's load area is not the highest portion of the picture, such as with a low sided open wagon or gondola. By inputting a <D> value you can "push" the load down to its proper resting surface, which in the above case, would be behind the walls of the wagon.  Using <D> is only helpful when the base picture is not transparent.  If the base picture is transparent, the correct  command is [OT: ].

If the overlay picture has transparent pixels, the picture is copied before  the base picture.

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.