Parametric geometric element definition and generation system and method

A method of computer aided 3D modelling of geometric objects undergoing changes wherein a directed acyclic graph is executed to instruct a rendering system to generate a 3D model, the directed acyclic graph including a plurality of nodes which are connected with other nodes with directed edges between two nodes, each node resenting a modelling operation of the geometric objects and each directed edge indicating the direction of flow of data from one node to another, comprising steps of:

• (a) executing continually the directed acyclic graph to instruct the rendering system to generate a series of frames of a 3D model of geometric objects which are undergoing changes,
• (b) measuring a time required for the rendering system to generate a predetermined numbers of preceding frames with respect to a target time,
• (c) modifying bound properties of one or more nodes, and
• (d) repeating iteratively steps (b) and (c) so that the time required for the rendering system to generate the most recent frame approach the target time.

A computer aided 3D modelling apparatus for modelling 3D model of geometric objects undergoing changes, comprising:

• an instruction storage module containing a directed acyclic graph to be executed to generate a 3D model, the directed acyclic graph including a plurality of nodes which are connected with other nodes with directed edges between two nodes, each node representing a modelling operation of the geometric objects and each directed edge indicating the direction of flow of data from one node to another,
• an input port for inputting changes in bound properties of one or more nodes,
• an instruction execution module for executing the directed acyclic graph to generate an output,
• an object player module for monitoring the output and regenerating the directed acyclic graph in response to the output if needed, and
• the rendering system for rendering the 3D model of geometric objects in response to the instructions.

A computer medium for computer aided 3D modelling of geometric objects undergoing changes, comprising;

• a storage module for storing a directed acyclic graph executable by a computer to generate a 3D model,
• the directed acyclic graph including a plurality of nodes which are connected each other with other nodes in a hierarchical tree with directed edges between two nodes, each node representing a modelling operation of the geometric objects and each directed edge indicating the direction of flow of data from one node to another,
• one of the plurality of nodes being adapted for sending a change event indication specifying changes to bound properties of the node to at least one other node in the hierarchical tree along associated directed edges,
• upon receiving the change event indication, each of the other nodes being adapted for determining based on preset rules if the received change event indication affects its bound properties, and
• each node being adapted for in succession sending a further change event indication to succeeding node when determining that the received change event indication affects its bound properties.