Cat Flap Ashley Ward Cat Flap and Cat tkeden model with visualisation This model was inspired by Simon Yung's LSD cat flap specification, catflapYung1994. Using ideas from this specification, I wrote my own LSD code, catflap.lsd. This spec was then rewritten in Eden, and a visualisation constructed using Donald and Scout. Notable features include a moving Scout window modelling the cat, sound effects using a system() call, a coloured Donald cat with various expressions, rescalable visualisation using the parameter simSize (see linkvis.e), placement of a Scout window in a Donald figure (involving some thought about the two different coordinate systems, using Mathematica), use of eager() to force the display to be updated whilst a procedure is active. The interaction between cat and flap in the "real world" seems a complex one. For example: does the cat actually move "inside" the flap before the flap responds by moving upwards? In the "real world" this is a continuous process... but it must be discretised for the model. There is at least one problem with the current model: if the cat changes direction halfway through the flap, the flap may remain hanging in mid air. The model really should have forces acting upon the flap as observables... 1997 12 catflapWard1997 MScM tkeden %eden %scout %donald screenshot_overall.gif catflapYung1994 simulation ~wmb/public/projects/simulations/catflap/ashley ~ashley/Open/Flap model