The default shape is the first collisionmesh setting and by far the most common.

Unlike the other shapes the default relies on internal groups/shapes, and its collision mesh will be a combination of all the shapes/groups internal shapes. E.g. If you make a floor with 3 boxes, group them together and set it to default shape, the group will then have the combined collision mesh of the 3 boxes. This means that almost all complex objects have at least several "default" subgroups.

If the default shape group contains non-grouped entities(lines, faces,...) it will act as a box shape.

Benefits of the default shape[]

The default shape allows the user to create complex models that have accurate collision parameters, allowing for a more realistic experience.

In comparison to staticmesh floors the default shapes ensure a quick simulation startup, and usualy alot simpler collision mesh that will let the simulation run faster, while still allowing it to move freely.

The UI
Joints SliderPistonHingeServoMotorGyroFixedCorkscrewSpringBallUniversalGears
States StaticFrozenIgnoreNoCollisionShowCollisionNoAutoFreezeMagnetic
Properties MagnetThrusterEmitterOnTouchOnTick
Shapes defaultboxspherecylinderconecapsulechamferconvexhullstaticmesh