1. A nontransitory storage medium encoded with instructions, for use with a plurality of computer systems, each one of which is in communication in real time over a network with other computer systems of the plurality of computer systems, wherein the instructions, when executed on each of the computer systems, establish, on each computer system, an application system, wherein the application system includes a simulation engine and a virtualized software environment, the simulation engine running on top of the virtualized software environment and enabling creation and editing of a project by a local user and network users, wherein the simulation engine comprises:a declaration processor that linearly processes a first declaration that constitutes a text embodiment of the project, reciting any set of items selected from the group consisting of object, relationship, property, behavior, and combinations thereof, into a declared scene tree of objects;
a scene tree object manager that (a) manages objects, their relationships, properties, and behaviors in the declared scene tree of objects, (b) causes transformation of the declared scene tree of objects so as to be mirrored in a project subnode of an instantiated scene tree of objects, the project subnode constituting an instantiated embodiment of the project, and (c) causes updating of the instantiated scene tree when it is changed;
a persistence processor in communication with the scene tree object manager, that causes mirroring, of the instantiated scene tree of objects, in a second declaration;
a visual editor, the visual editor being a subnode of the instantiated scene tree, that makes user-directed changes to the project subnode of the instantiated scene tree, wherein the project subnode is a subnode of the visual editor;
an editor broadcaster, the editor broadcaster being a subnode of the instantiated scene tree, coupled to the network, that obtains changes from the visual editor and causes the persistence processor to transform a correspondingly changed part of the instantiated scene tree into a change declaration and broadcasts the change declaration embedded in a change message over the network to the other computer systems; and
an editor listener, the editor listener being a subnode of the instantiated scene tree, coupled to the network, that receives and processes any change message, from any other of the computer systems, by causing the declaration processor to transform a declaration embedded in received change message into a corresponding change in the instantiated scene tree;
a rendering processor, coupled to the virtualized software environment, to requisition hardware resources to cause physical manifestation of the instantiated scene tree of objects in a form selected from the group consisting of audio, visual, network communication, storage in a transitory or a nontransitory basis, computational tasks, and combinations thereof, the physical manifestation being optimized by evaluation of hardware resources that are both available and required to be allocated in order to achieve the physical manifestation.