An object is an entity in the game that is not part of the level geometry of the course. Most objects either interact with Mario and/or move in some way, act as stationary platforms or simply exist for aesthetic purposes. The maximum number of objects in a course is 240.
Every object is part of a larger "group" that helps define its behavior. Of the 12 groups, some are more strongly defined than others, but it helps to categorize objects within the game.
The first group, this group is composed of "playable" characters, which is simply Mario. Had Luigi been finished, it's possible he would have been in this group.
This group is unused, it is possible this would have been a Luigi group, too.
The destructive group consists of (non-playable) objects able to destroy other objects. This group consists specifically of four objects- Bob-omb, Bob-omb explosion, cork shell, and a beta object that was unused.
Like the second group, this one is also unused.
Actors are generally what are described as "alive", such as bullet bills, bully, MIPS, etc.
This group consists of objects able to push other (non-playable) objects. This behavior often goes along with transport cloning. This group consists of objects such as goomba, koopa, and spiny.
This group consists of objects within levels that are interactable, such as hearts and stars. This group often acts as "catch-all" along with default.
Group 7 is another unused group.
If an object isn't put into a different group, it ends up here. For this reason, this group acts as a "catch-all" for odd objects.
These are any items that have surface collision, specifically walls, floor, and ceilings. Often these are items that would be easy to consider just part of the course geometry, such as the submarine in DDD or ship in JRB. Worth noting- this group is a requirement to have surfaces, so objects like Whomp and Thwomp still fall into this category despite being "actors".
The polelike group consists of objects that could be described as "radial" in that the attract Mario to some sort of radial center. This includes poles, whirlpools, tornados, trees, etc.
This group consists of most objects that spawn other objects, like coin spawners or star spawners.
Unimportant objects generally do not affect gameplay at all and exist purely for visuals. This group has the unique quality of unloading to stay under the object limit, hence their "unimportant" name. Some examples include smoke, wind, and dust.
During a frame, object lists are processed in the following order: Spawner, Surface, Polelike, Player, Pushable, General, Destructive, Level, Default, Unimportant
The Object limit is the maximum number of important objects a course can have loaded simultaneously before the game cannot handle loading any more. This limit is 240 at all times, but the debug code that displays object count fails to count certain spawnerswhich?, making this limit seem lower in some coursescitation needed. This doesn't apply to the total objects in the course, only to ones that are loaded at the time. Unloaded objects use no slots. As the object limit is approached, unimportant objects will sacrifice their slots in order to empty them for important objects. If no vacant slots are available when any object (important or unimportant) is loaded, a crash will occur.
- Clones never unload and thus occupy object slots even when the original object is unloaded.
- PUs don't naturally contain any objects, but they can be brought there.