The box is one of the basic types of shapes available in sketchyphysics. In it, the object's collisionmesh will simply be the bounding box. This setting is default for what is created with the "box" tool. (duh)

If you must explode a box object that is set at an angle, be sure to first rotate it so that it is parallel to one of the axis, then move it back into position. Otherwise, the new bounding box will affect the collision detection.

The UI
Joints SliderPistonHingeServoMotorGyroFixedCorkscrewSpringBallUniversalGears
States StaticFrozenIgnoreNoCollisionShowCollisionNoAutoFreezeMagnetic
Properties MagnetThrusterEmitterOnTouchOnTick
Shapes defaultboxspherecylinderconecapsulechamferconvexhullstaticmesh