Method and apparatus for interactively manipulating and displaying presumptive relationships between graphic objects

Abstract

A presumptive mode computer aided design and drafting system for interactively manipulating and displaying graphic objects that employ predefined rules to govern the geometric layout and logical relationships representing a physical design, schematic or process flow diagram. The system is configured to comply with the rules employed by various design disciplines. Specific interactive computer graphics behavior is dynamically accessed to interactively update graphic object relationships according to rules of geometric conduct. The rules of geometric conduct may be stored in external databases along with parameters to verify the logical relationships of the graphic objects used in the drawing. Object orientation is employed in the software design of the system to allow new devcies or procedures to adopt the behavior of existing definitions. In the preferred embodiment, a selected object floats with a cursor in a graphic environment until located in proximity with underlying graphic objects. The selected object then aligns, jumps and clings to the underlying graphic object or objects according to predetermined rules. For example, the object is automatically rotated, orientated and positioned relative to a cling point into a correct relationship with the underlying object without further input by the operator. Further, the selected object slides along the underlying graphic object maintaining the correct geometric relationship while the operator moves the cursor in proximity with the underlying graphic. The operator either accepts the presumed relationship or moves the cursor away to uncling the selected object.

1. A method of operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;    determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;    manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules; and    dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object.    
     
     
       2. The  A method of  claim 1 ,  operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object; 
 wherein the predetermined proximity is a location tolerance before said manipulating step and converts to a larger rejection tolerance during said maintaining  dynamically updating step.  
 
     
     
       3. The  A method of  claim 1   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, wherein said manipulating step comprises the step of:  orientating the selected graphic object according to a tangential angle with respect to the underlying graphic object at a cling point; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object. 
 
     
     
       4. The method of  claim 1 , wherein said manipulating step includes the step of:
 positioning the selected graphic object at a predetermined offset relative to the underlying graphic object.    
     
     
       5. The  A method of  claim 4   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, wherein the underlying graphic object has two sides, ;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, wherein said manipulating step includes the step of positioning the selected graphic object at a predetermined offset relative to the underlying graphic object; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, and during said maintaining  dynamically updating step, further comprising the step of:  moving the selected graphic object to the opposite side of the underlying graphic object when the graphic pointing symbol is moved to the opposite side.  
 
     
     
       6. The method of  claim 5 , wherein said maintaining  dynamically updating step further comprises the step of:
 mirroring the selected graphic object about the underlying graphic object when moved to the opposite side of the underlying graphic object.  
 
     
     
       7. The method of  claim 6 , wherein said maintaining  dynamically updating step further comprises the step of:
 mirroring the selected graphic object about a perpendicular offset line when moved to the opposite side of the underlying graphic object.  
 
     
     
       8. The method of  claim 5 , wherein said maintaining  dynamically updating step further comprises the step of:
 mirroring the selected graphic object about a perpendicular offset line when moved to the opposite side of the underlying graphic object.  
 
     
     
       9. The  A method of  claim 1   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and after said manipulating step, further comprising the step of:  modifying the underlying graphic object according to the predetermined geometric rules; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object.  
 
     
     
       10. The method of  claim 9 , wherein said modifying step comprises the step of:
 dividing the underlying graphic object into two separate underlying graphic objects for inserting the selected graphic object therebetween.  
 
     
     
       11. The method of  claim 10 , wherein said modifying step further comprises the step of:
 deleting a portion of the original underling graphic object for inserting the selected graphic object.  
 
     
     
       12. The  A method of  claim 1   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol, wherein the selected graphic object includes at least one alignment vector;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, said manipulating step further comprising the step of:  aligning the selected graphic object with the underlying graphic object according to the alignment vector; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object.  
 
     
     
       13. The method of claim  1   12 , wherein the selected graphic object and the underlying graphic object each have an alignment vector, wherein said manipulating step comprises the step of:
 aligning the selected graphic object with the underlying graphic object by aligning the alignment vectors.  
 
     
     
       14. The  A method of  claim 1   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol, wherein the selected graphic object includes a clip region;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, said manipulating step further comprising the step of:  partially deleting the underlying graphic object according to the clip region; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object.  
 
     
     
       15. The method of  claim 14 , wherein the underlying graphic object comprises a plurality of graphic objects, said partially deleting step further comprising the step of:
 partially deleting only selected ones of the plurality of graphic objects corresponding to the clip region.  
 
     
     
       16. The  A method of  claim 1   operating a computer aided design system in presumptive mode, comprising the steps of:
 moving a selected graphic object relative to a graphic pointing symbol;  
 determining when the selected graphic object is within a predetermined proximity of an underlying graphic object;  
 manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules; and  
 dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein said maintaining  dynamically updating step further comprises the steps of:  clinging the selected graphic object to an initial cling point;  and rotating the selected graphic object about the initial cling point corresponding to movement of the graphic pointing symbol.  
 
     
     
       17. The method of claim  1   16 , further comprising the step of:
 unclinging the selected graphic object from the underlying graphic object to move with the graphic pointing symbol when the graphic pointing symbol is moved a greater distance than the predetermined proximity from the underlying graphic object.  
 
     
     
       18. The method of claim  1   16 , wherein said maintaining  dynamically updating step includes the step of:
 moving the selected graphic object relative to a sliding cling point along the underlying graphic object where the cling point moves relative to the graphic pointing symbol as the graphic pointing symbol is moved within the predetermined proximity of the underlying graphic object.  
 
     
     
       19. The method of  claim 18 , wherein said maintaining  dynamically updating step further comprises the step of:
 interactively modifying the underlying graphic object according to the predetermined rules and relative to the sliding cling point as the graphic pointing symbol is moved.  
 
     
     
       20. The method of  claim 18 , wherein the underlying graphic object included a primary vector and a secondary vector, the selected graphic object having a first alignment vector and a second alignment vector, wherein said manipulating and maintaining  dynamically updating steps further comprise the steps of:
 aligning the selected graphic object with the primary vector according to the first alignment vector when the first alignment vector is within a predetermined proximity of the primary vector; and  
 aligning the selected graphic object with the secondary vector according to the second alignment vector when the second alignment vector is within a predetermined proximity of the secondary vector.  
 
     
     
       21. A method of operating a computer aided design system, comprising the steps of:
 providing at least one graphic object to be selected for insertion into a graphic design;    displaying and moving a selected graphic object with a graphic cursor moved within the graphic design;    when the selected graphic object is within a predetermined proximity with respect to one or more underlying graphic objects, automatically manipulating the object into a geometric relationship with the underlying graphic object; and    dynamically updating the geometric relationship based on movement of the graphic cursor while the graphic cursor remains within the predetermined proximity of the underlying graphic object.    
     
     
       22. The  A method of  claim 21   operating a computer aided design system, comprising the steps of:
 providing at least one graphic object to be selected for insertion into a graphic design;  
 displaying and moving a selected graphic object with a graphic cursor moved within the graphic design;  
 when the selected graphic object is within a predetermined proximity with respect to one or more underlying graphic objects, automatically manipulating the object into a geometric relationship with the underlying graphic object, wherein said manipulating step comprises the steps of:  orienting the selected graphic object relative to a cling point along the underlying graphic object;  and positioning the selected graphic object at a predetermined offset relative to the cling point; and dynamically updating the geometric relationship based on movement of the graphic cursor while the graphic cursor remains within the predetermined proximity of the underlying graphic object.  
 
     
     
       23. The method of  claim 22 , further comprising the step of:
 continually re-orienting and re-positioning the selected graphic object relative to a sliding cling point which moves relative to the graphic cursor as it is moved within the predetermined proximity.  
 
     
     
       24. A presumptive mode computer aided design system for interactively manipulating and displaying a selected object according to predefined geometric relationships, comprising:
 a display device for displaying a graphic environment;    memory for storing data, including: 
 a data base defining geometric relationships among graphic objects;  
 a plurality of graphic object files, each defining a corresponding graphic object and associated symbol for display in said graphic environment; and  
 a design file for incorporating a plurality of underlying graphic objects according to said geometric relationships;  
   a pointing device for receiving input from an operator; and    a processor coupled to said memory, said display device and said pointing device for controlling said graphic environment;    wherein the operator selects an object for insertion into said design file and manipulates a graphic cursor in proximity with one of said underlying graphic objects displayed in said geometric environment, wherein said processor moves said selected object with said graphic cursor and then manipulates said graphic object and said design file in to a geometric relationship when said selected object is within proximity with said one of said underlying graphic objects, and wherein said processor dynamically updates said geometric relationship based on movement of said graphic cursor while said graphic cursor is within proximity of said underlying graphic objects.    
     
     
       25. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein the predetermined proximity is a location tolerance before said means for manipulating and converts to a larger rejection tolerance during said means for dynamically updating.   
     
     
       26. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein said means for manipulating comprises means for orienting the selected graphic object according to a tangential angle with respect to the underlying graphic object at a cling point.   
     
     
       27. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, wherein the underlying graphic object has two sides, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein said means for manipulating includes means for positioning the selected graphic object at a predetermined offset relative to the underlying graphic object, and during said means for dynamically updating, further comprising means for moving the selected graphic object to the opposite side of the underlying graphic object when the graphic pointing symbol is moved to the opposite side.   
     
     
       28. The system of  claim 27 , wherein said means for dynamically updating further comprises:
 means for mirroring the selected graphic object about the underlying graphic object when moved to the opposite side of the underlying graphic object.   
     
     
       29. The system of  claim 28 , wherein said means for dynamically updating further comprises:
 means for mirroring the selected graphic object about a perpendicular offset line when moved to the opposite side of the underlying graphic object.   
     
     
       30. The system of  claim 27 , wherein said means for dynamically updating further comprises:
 means for mirroring the selected graphic object about a perpendicular offset line when moved to the opposite side of the underlying graphic object.   
     
     
       31. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, and after said means for manipulating, further comprising means for modifying the underlying graphic object according to the predetermined geometric rules.   
     
     
       32. The system of  claim 31 , wherein said means for modifying comprises:
 means for dividing the underlying graphic object into two separate underlying graphic objects for inserting the selected graphic object therebetween.   
     
     
       33. The system of  claim 32 , wherein said means for modifying further comprises:
 means for deleting a portion of the original underlying graphic object for inserting the selected graphic object.   
     
     
       34. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein the selected graphic object includes at least one alignment vector, and said means for manipulating further comprises means for aligning the selected graphic object with the underlying graphic object according to the alignment vector.   
     
     
       35. The system of  claim 34 , wherein the selected graphic object and the underlying graphic object each have an alignment vector, wherein said means for manipulating comprises:
 means for aligning the selected graphic object with the underlying graphic object by aligning the alignment vectors.   
     
     
       36. A computer aided design system comprising:
   a computer;      means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein the selected graphic object includes a clip region, and said means for manipulating further comprises means for partially deleting the underlying graphic object according to the clip region.   
     
     
       37. The system of  claim 36 , wherein the underlying graphic object comprises a plurality of graphic objects, said means for partially deleting further comprising:
 means for partially deleting only selected ones of the plurality of graphic objects corresponding to the clip region.   
     
     
       38. A computer aided design system, comprising:
 a computer;      means, performed by the computer, for moving a selected graphic object relative to a graphic pointing symbol, for determining when the selected graphic object is within a predetermined proximity of an underlying graphic object, for manipulating the selected graphic object into a geometric relationship with the underlying graphic object according to predetermined geometric rules, and for dynamically updating the geometric relationship based on movement of the graphic pointing symbol while the graphic pointing symbol remains within the predetermined proximity of the underlying graphic object, wherein said means for dynamically updating further comprises means for clinging the selected graphic object to an initial cling point and means for rotating the selected graphic object about the initial cling point corresponding to movement of the graphic pointing symbol.     
     
     
       39. The system of  claim 38 , further comprising:
 means for unclinging the selected graphic object from the underlying graphic object to move with the graphic pointing symbol when the graphic pointing symbol is moved a greater distance than the predetermined proximity from the underlying graphic object.   
     
     
       40. The system of  claim 38 , wherein said means for dynamically updating includes:
 means for moving the selected graphic object relative to a sliding cling point along the underlying graphic object where the cling point moves relative to the graphic pointing symbol as the graphic pointing symbol is moved within the predetermined proximity of the underlying graphic object.   
     
     
       41. The system of  claim 40 , wherein said means for dynamically updating further comprises:
 means for interactively modifying the underlying graphic object according to the predetermined rules and relative to the sliding cling point as the graphic pointing symbol is moved.   
     
     
       42. The system of  claim 40 , wherein the underlying graphic object includes a primary vector and a secondary vector, the selected graphic object having a first alignment vector and a second alignment vector, wherein said means for manipulating and means for dynamically updating further comprises:
 means for aligning the selected graphic object with the primary vector according to the first alignment vector when the first alignment vector is within a predetermined proximity of the primary vector; and    means for aligning the selected graphic object with the secondary vector according to the second alignment vector when the second alignment vector is within a predetermined proximity of the secondary vector.   
     
     
       43. A computer aided design system, comprising:
 a computer;    means, performed by the computer, for providing at least one graphic object to be selected for insertion into a graphic design and for displaying and moving a selected graphic object with a graphic cursor moved within the graphic design;    means, performed by the computer, for automatically manipulating the object into a geometric relationship with the underlying graphic object when the selected graphic object is within a predetermined proximity with respect to one or more underlying graphic objects; and    means, performed by the computer, for dynamically updating the geometric relationship based on movement of the graphic cursor while the graphic cursor remains within the predetermined proximity of the underlying graphic object, wherein said means for manipulating comprises means for orienting the selected graphic object relative to a cling point along the underlying graphic object and means for positioning the selected graphic object at a predetermined offset relative to the cling point.   
     
     
       44. The system of  claim 43 , further comprising:
 means for continually re-orienting and re-positioning the selected graphic object relative to a sliding cling point which moves relative to the graphic cursor as it is moved within the predetermined proximity.   
     
     
       45. A method of operating a computer-aided design system, comprising:
 (a) displaying a first graphic object on a computer; and    (b) displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object, wherein the points of interest are identified by predefined rules and the predefined rules perform one or more geometric computations selected from a group comprising tangent, offset, parallel, alignment, end point, major vector, divided segment, extended segment, and intersection computations.   
     
     
       46. The method of  claim 45 , wherein a position of the pointing symbol is controlled by an input device coupled to the computer. 
     
     
       47. The method of  claim 45 , wherein the predefined rules limit selection of the first graphic object. 
     
     
       48. A method of operating a computer-aided design system, comprising:
 (a) displaying a first graphic object on a computer;    (b) displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object; and    (c) displaying a second graphic object and joining the first and second graphic objects when the pointing symbol is moved to within a predetermined location tolerance of the first graphic object.   
     
     
       49. The method of  claim 48 , wherein the predetermined location tolerance identifies a minimum perpendicular distance which determines when the second graphic object is close enough to the first graphic object to establish an association therebetween. 
     
     
       50. The method of  claim 48 , wherein the second graphic object is joined to the first graphic object when a designated origin point of the second graphic object moves to within the predetermined location tolerance with respect to the first graphic object. 
     
     
       51. The method of  claim 48 , further comprising separating the first and second graphic objects when the pointing symbol is moved to beyond a predetermined rejection tolerance of the first graphic object. 
     
     
       52. The method of  claim 48 , wherein the joining step comprise joining the first and second graphic objects at one or more of the points of interest. 
     
     
       53. The method of  claim 48 , wherein the first and second graphic objects are joined according to one or more characteristics selected from a group comprising a predefined offset, orientation, and rotation. 
     
     
       54. The method of  claim 48 , further comprising dynamically updating a relationship between the first and second graphic objects as the pointing symbol is moved. 
     
     
       55. The method of  claim 54 , wherein the dynamically updating step comprises repositioning the second graphic object relative to the first graphic object as the pointing symbol is moved. 
     
     
       56. A method of operating a computer-aided system, comprising:
 (a) displaying a first graphic object on a computer; and    (b) displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object, wherein the points of interest are cling points.   
     
     
       57. The method of  claim 56 , further comprising displaying a second graphic object and clinging the second graphic object to the first graphic object according to at least one predefined cling characteristic. 
     
     
       58. The method of  claim 57 , wherein the cling characteristic comprises at least one characteristic selected from a group comprising:
 joining the second graphic object to the first graphic object via a shortest distance where the origin of the second graphic object aligns and is coincident with a closest point of interest on the first graphic object,    sliding the second graphic object in alignment with the first graphic object as the pointing symbol is moved,    rotating the second graphic object about at least one of the points of interest on the first graphic object by manipulating the pointing symbol around the point,    positioning the second graphic object at an opposite side of the first graphic object when the pointing symbol traverses from one side to another of the first graphic object, and    positioning the second graphic object at a  180 -degree rotation of the first graphic object at a specified perpendicular offset in a direction of the pointing symbol.   
     
     
       59. The method of  claim 58 , further comprising unclinging the second graphic object from the first graphic object at the pointing symbol is moved a distance greater than a predetermined rejection tolerance away from the first graphic object. 
     
     
       60. A computer- aided design system, comprising:    (a) a computer; and    (b) means, performed by the computer, for displaying a first graphic object on a computer and for displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object, wherein the points of interest are identified by predefined rules and the predefined rules perform one or more geometric computations selected from a group comprising tangent, offset, parallel, alignment, end point, major vector, divided segment, extended segment, and intersection computations.   
     
     
       61. The system of  claim 60 , wherein a position of the pointing symbol is controlled by an input device coupled to the computer. 
     
     
       62. The system of  claim 60 , wherein the predefined rules limit selection of the first graphic object. 
     
     
       63. A computer-aided design system, comprising:
 (a) a computer; and    (b) means, performed by the computer, for displaying a first graphic object on a computer, for displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object, and for displaying a second graphic object and joining the first and second graphic objects when the pointing symbol is moved to within a predetermined location tolerance of the first graphic object.   
     
     
       64. The system of  claim 63 , wherein the predetermined location tolerance identifies a minimum perpendicular distance which determines when the second graphic object is close enough to the first graphic object to establish an association therebetween. 
     
     
       65. The system of  claim 63 , wherein the second graphic object is joined to the first graphic object when a designated origin point of the second graphic object moves to within the predetermined location tolerance with respect to the first graphic object. 
     
     
       66. The system of  claim 63 , further comprising means for separating the first and second graphic objects when the pointing symbol is moved to beyond a predetermined rejection tolerance of the first graphic object. 
     
     
       67. The system of  claim 63 , wherein the means for joining comprises means for joining the first and second graphic objects at one or more of the points of interest. 
     
     
       68. The system of  claim 63 , wherein the first and second graphic objects are joined according to one or more characteristics selected from a group comprising a predefined offset, orientation, and rotation. 
     
     
       69. The system of  claim 63 , further comprising means for dynamically updating a relationship between the first and second graphic objects as the pointing symbol is moved. 
     
     
       70. The system of  claim 69 , wherein the means for dynamically updating comprises means for repositioning the second graphic object relative to the first graphic object as the pointing symbol is moved. 
     
     
       71. A computer-aided design system, comprising:
 (a) a computer; and    (b) means, performed by the computer, for displaying a first graphic object on a computer and for displaying at least one point of interest on the computer when a pointing symbol is within a predetermined proximity of the first graphic object, wherein the points of interest are cling points.   
     
     
       72. The system of  claim 71 , further comprising means for displaying a second graphic object and clinging the second graphic object to the first graphic object according to at least one predefined cling characteristic. 
     
     
       73. The system of  claim 72 , wherein the cling characteristic comprises at least one characteristic selected from a group comprising:
 joining the second graphic object to the first graphic object via a shortest distance where the origin of the second graphic object aligns and is coincident with a closest point of interest on the first graphic object,    sliding the second graphic object in alignment with the first graphic object as the pointing symbol is moved,    rotating the second graphic object about at least one of the points of interest on the first graphic object by manipulating the pointing symbol around the point,    positioning the second graphic object at an opposite side of the first graphic object when the pointing symbol traverses from one side to another of the first graphic object, and    positioning the second graphic object at a  180 -degree rotation of the first graphic object at a specified perpendicular offset in a direction of the pointing symbol.   
     
     
       74. The system of  claim 72 , further comprising means for unclinging the second graphic object from the first graphic object as the pointing symbol is moved a distance greater than a predetermined rejection tolerance away from the first graphic object.