Method for generating graphical models

Claim 2

Method for generating graphical models of 2- or 3-dimensional objects with at least partially variable dimensions, in particular mechanical parts, in a computer aided design system comprising a set of design commands preferably represented by command keys (27), characterized in that said computer aided design system (1.1) in an object entry mode, (1.1.1) associates a predefined restriction with each of the commands of a certain sub-group of said set of design commands, (1.1.2) stores the associated restriction or a representation of the same for further processing if a command out of said sub-group is entered by the user, (1.2) in a retrieval mode wherein said variable dimensions are replaced by actual values, (1.2.1) retrieves said restrictions and uses them to build the graphical model of an actual object.

Claim 3

Method according to claim 1, characterized in that said predefined restric­tion is at least one of the following list: - Horizontal line, - Vertical line, - Parallel line, - Orthogonal line (Right angle), - Tangential line, - Colinear line, - Concentric circle.

Claim 4

Method according to claim 1 or 2, characterized in that said computer aided design system (3.1) in said object entry mode, records the sequence of design com­mands as entered by the user; (3.2) in said retrieval mode, retrieves said sequence of design commands and builds the graphical model of the actual object in successive steps following said sequence.

Claim 5

Method according to at least one of the preceding claims, characterized in that in object entry mode, the user may enter the value of a geometrical dimension either as (4.1) a fixed dimension which cannot be altered thereafter or (4.2) a variable dimension which is then assigned an actual value in retrieval mode.

Claim 6

Method according to claim 4, characterized in that in object entry mode, the user may further enter the value of a geometrical dimension as (5.1) a flexible dimension which is defined by two already defined geometrical positions.

Claim 7

Computer aided design system comprising (6.1) at least one user input interface, preferably a keyboard and/or a graphics tablet (26); (6.2) at least one user output interface, preferably a screen with graphics capabilities (31) and/or a plotter (32); (6.3) a digital processor (24) being connected with said user input inter­face and said user output interface, preferably via appropriate registers (25,33), and further being connected with a program memory (29) containing instructions to operate said digital proces­sor (24), characterized in that (6.4) said user input interface comprises a set of design command entry means, preferably keys (27) of said graphics tablet (26), which are logically devided into at least two sub-groups, (6.4.1) in the first of these sub-groups (27b) each command being associated with a predefined restriction, (6.5) said program memory (29) contains instructions (6.5.1) to store the associated restriction or a representation of the same for farther processing if a command of said first sub-group (27b) is entered, (6.5.2) to retrieve said restrictions and use them to build the graphical model of an actual object.

Claim 8

Computer aided design system comprising (6.1) at least one user input interface, preferably a keyboard and/or a graphics tablet (26); (6.2) at least one user output interface, preferably a screen with graphics capabilities (31) and/or a plotter (32); (6.3) a digital processor (24) being connected with said user input inter­face and said user output interface, preferably via appropriate registers (25,33), and further being connected with a program memory (29) containing instructions to operate said digital proces­sor (24), characterized in that (6.4) said user input interface comprises a set of design command entry means, preferably keys (27) of said graphics tablet (26), which are logically devided into at least two sub-groups, (6.4.1) in the first of these sub-groups (27b) each command being associated with a predefined restriction, (6.5) said program memory (29) contains instructions (6.5.1) to store the associated restriction or a representation of the same for farther processing if a command of said first sub-group (27b) is entered, (6.5.2) to retrieve said restrictions and use them to build the graphical model of an actual object.

Claim 9

Computer aided design system according to claim 6, characterized by a data memory (30) containing, as a representation of each design command, at least (6.1) a representation of that command and/or its operation which is preferably also representative of a restriction eventually associated with that command, and (6.2) the dimension of the associated geometrical item, preferably as a fixed dimension or as a variable or symbolic dimension.

Claim 10

Computer aided design system according to claim 6 or 7, characterized in that said program memory (29) contains instructions (8.1) to store the sequence of design commands as entered by the user, preferably by storing the design commands in the same order as entered by the user or by assigning an index number to any design command, these indices indicating their input order, (8.2) to retrieve the sequence of design commands and use them to build the graphical model of an actual object in the same order as entered by the user.

Claim 11

Computer aided design system according to at least one of claims 6 to 8, characterized in that said program memory (29) contains instructions en­abling the user to enter, in an object entry mode, the value of a geometri­cal dimension either as (9.1) a fixed dimension which cannot be altered thereafter or (9.2) a variable dimension which is then assigned an actual value in a retrieval mode.

Claim 12

Computer aided design system according to claim 9, characterized in that said program memory (29) contains instructions further enabling the user to enter, in object entry mode, the value of a geometrical dimension as (10.3) a flexible dimension which is defined by two already defined geometrical positions.