One limitation of SketchyPhysics is that objects that are below a certain size will not move. If your individual door panels are very thin, for instance, they will not move. If you connect several thin panels together with joints, then group them all into a single group, that group will be large enough to move in the SketchyPhysics environment, but the panels themselves will be frozen relative to each other.
Sometimes, you need to scale everything up to make a simulation work, even though your dimensions will be proportionately larger than in real life.