System and method for coding and retrieval of a CAD drawing from a database

A method of coding a view from a 3-dimensional CAD model, the method comprising:

• a) deriving a 2-dimensional view from the 3-dimensional CAD model;
• b) identifying a feature of the view, wherein the feature comprises a graphic entity or a group of graphic entities;
• c) extracting properties of the feature from the CAD model, wherein the properties include vector properties associated with the graphic entity or group of graphic entities;
• d) generating code bits representative of the extracted properties;
• e) adding the code bits to a view code for the view;
• and
• f) storing the view code.

A method of coding a view in a CAD drawing, the method comprising:

• a) identifying a feature of the view, wherein the feature comprises a graphic entity or a group of graphic entities;
• b) extracting properties of the feature from the CAD drawing, wherein the properties include vector properties associated with the graphic entity or group of graphic entities;
• c) generating code bits representative of the extracted properties;
• d) adding the code bits to a view code for the view;
• and
• e) storing the view code.

A method of selecting a CAD drawing for retrieval from a database of drawings, the method comprising:

• a) producing a CAD source drawing comprising a source view;
• b) identifying a feature of the source view, wherein the feature comprises a graphic entity or a group of graphic entities;
• c) extracting properties of the feature from the CAD source drawing, wherein the properties include vector properties associated with the graphic entity or group of graphic entities;
• d) generating code bits representative of the extracted properties;
• e) adding the code bits to a source view code for the source view;
• f) comparing the source view code with each of a plurality of stored view codes and calculating a similarity index for each stored view code of the plurality;
• and
• g) selecting the drawing for retrieval from the database on the basis of the similarity index.

A drawing retrieval system for a CAD system comprising means for entering and means for displaying a drawing, and a memory for storing data including a database of drawings, the drawing retrieval system comprising:

• a) identifying means for identifying a feature of a view in a drawing, wherein the feature comprises a graphic entity or a group of graphic entities;
• b) means for extracting properties of the feature, wherein the properties include vector properties associated with the entity or group of entities;
• c) coding means for generating code bits representative of the extracted properties and for adding the code bits to a view code for the view;
• d) means for storing the view code in the memory;
• e) comparing means for comparing (i) a first view code of a first view in a first drawing entered in the entering means with (ii) a second view code of a second view in a second drawing in the database, to derive a similarity index indicative of a degree of similarity between the first view and the second view;
• and
• f) means for presenting, on the basis of the similarity index, a list of drawings from which a user can select for retrieval from the database means for retrieving a selected drawing from the database for display on the display means.

A software carrier comprising computer readable instructions for controlling a computer to code a view in a CAD drawing, including instructions for:

• a) identifying a feature of the view, wherein the feature comprises a graphic entity or a group of graphic entities;
• b) extracting properties of the feature from the CAD drawing, wherein the properties include vector properties associated with the graphic entity or group of graphic entities;
• c) generating code bits representative of the extracted properties;
• d) adding the code bits to a view code for the view;
• and
• e) storing the view code.

A software carrier comprising computer readable instructions for controlling a computer to facilitate selection by a user of a CAD drawing for retrieval from a database of CAD drawings, each CAD drawing in the database comprising at least one view that has been coded by:

• a) identifying a feature of the view, wherein the feature comprises a graphic entity or a group of graphic entities;
• b) extracting properties of the feature from the CAD drawing containing the view, wherein the properties include vector properties associated with the graphic entity or group of graphic entities;
• c) generating code bits representative of the extracted properties;
• and
• d) adding the code bits to a view code for the source view;
• wherein the computer readable instructions include instructions for:
• i) producing a CAD source drawing comprising a source view;
• ii) coding the source view in accordance with steps a) to d) above;
• iii) comparing the source view code with each of a plurality of stored codes of views in the database of drawings to calculate a similarity index for each stored view code;
• and
• iv) on the basis of the similarity index, presenting a list of drawings from which the user can select for retrieval from the database.

A method for determining data ranges of a vector property of a graphic entity in a set of drawings, the method comprising:

• a) determining a sample of views from said set of drawings;
• b) selecting a view from said sample of views;
• c) identifying said graphic entity in said view;
• d) extracting said vector property of said graphic entity in said selected view;
• e) repeating steps b) to d) for the other views in the sample of views;
• f) determining a minimum and a maximum value of said extracted vector properties;
• and
• g) assigning data ranges to said vector properties on the basis of said maximum and minimum values.

A method of producing a model code directly from a 3-dimensional CAD model, the method comprising:

• a) identifying a feature in the 3-dimensional CAD model comprising a geometrical entity or a group of geometrical entities;
• b) extracting properties of the feature from the CAD model, wherein the properties include vector properties associated with the geometrical entity or group of geometrical entities;
• c) generating code bits representative of the extracted properties;
• e) adding the code bits to a model code for the model;
• and
• f) storing the model code.