Method of tracing a drawing and apparatus for embodying the method

• US 5,469,537 A
• Filed: 10/28/1993
• Issued: 11/21/1995
• Est. Priority Date: 10/28/1992
• Status: Expired due to Fees

• Current Assignee: International Technical Illustration Company Limited
• Original Assignee: International Technical Illustration Company Limited
• Inventors: Seki, Nobuhiro
• Primary Examiner(s): Jankus, Almis R.
• Application Number:
  US08/141,958
• Time in Patent Office: 754 Days
• Field of Search: 395/133-139, 395/140, 395/141, 395/142, 395/155, 395/161, 395/162, 364/474.29, 382/60
• US Class Current: 345/619
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects

Abstract

A novel method of tracing a drawing and a novel apparatus for implementing this method. The method and the apparatus presented by the invention can correctly and quickly trace an ellipse from a draft plan. Initially, a display unit displays a draft plan which has been read by an image scanner, and then, the apparatus generates vector data corresponding to the draft plan by activating its own drawing function to trace the draft plan shown on the display screen. The apparatus computes length m0 of a long diameter and length m1 of a short diameter of an ellipse E of the draft plan by directly designating a pair of points Pi0 and Pi1 corresponding to both ends of the short diameter of the ellipse E and another pair of points Pj0 and Pj1 corresponding to both ends of the short diameter of the ellipse E. At the same time, the apparatus computes the direction D and the center point P0 of the long diameter corresponding to the center of the ellipse E, and then, based on those data of length m0 and m 1 of the long and short diameters, the direction D, and the center point P0 of the long diameter, the apparatus eventually generates vector data of the ellipse E. Known ratios for ellipses in specific projection drawings, e.g., an isometric projection, are stored in memory means and may be utilized in generating the vector data.

Claims

1. A method of tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace said draft plan displayed on a display unit while displaying said draft plan, read by an image scanner, on said display unit, which method comprises sequential steps including the following:

a step of computing a length m0 of a long diameter and a length m1 of a short diameter of an ellipse E of said draft plan, computing direction D of said long diameter, and center point P0 of said long diameter corresponding to the center of said ellipse E, directly designating a pair of points Pi0 and Pi1 corresponding to both ends of said long diameter and another pair of points Pj0 and Pj1 corresponding to both ends of said short diameter of said ellipse E of said draft plan; and

a step of generating vector data of said ellipse E based on said length m0 of said long diameter, said length m1 of said short diameter, said direction D, and said center point P0 of said long diameter of said ellipse E thereof.

2. A method of tracing a drawing, which generates vector data corresponding to a draft plan displayed on a display unit by activating a drawing function to trace said draft plan displayed on a display unit on a specific projection drawing, which method comprises sequential steps including the following:

a step of designating a specific projection surface in said specific projection drawing;

a step of designating a pair of points Pi0 and Pi1 corresponding to a long diameter of an ellipse E of said draft plan;

a step of computing a length m0 of said long diameter and center point P0 of said long diameter corresponding to the center of said ellipse E;

a step of computing a length m1 of a short diameter of said ellipse based on a known ratio S of said long diameter and a short diameter of an ellipse on said specific projection surface corresponding to a circle on a plane surface and said computed length m0 of said long diameter; and

a step of generating vector data from a direction D of said long diameter specified by said length m0 of said long diameter, said length m1 of said short diameter, said center point P0 of said long diameter, and the projection surface.

3. A method of tracing a drawing as defined in claim 2, wherein said specific projection drawing is substantially an isometric projection drawing.

4. A method of tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace a draft plan displayed on a display unit on a specific projection drawing, said method comprising sequential steps including the following:

a step of designating a specific projection surface in said specific projection drawing;

a step of designating a pair of points Pk0 and Pk1 corresponding to intersecting points of the ellipse E of said draft plan and a straight line L, which is a reference direction in said projection drawing and passes through the center of said ellipse E of said draft plan;

a step of computing a length n between said points Pk0 and Pk1, and the center point P0 of said length n;

a step of computing a length m0 of a long diameter and m1 of a short diameter based on a ratio U of said length n and said length m0 and a ratio V of said length n and said length m1 of the ellipse E of said specific projection surface; and

a step of generating vector data from a direction D of said long diameter specified by said length m0 of said long diameter, said length m1 of said short diameter, said center point P0 of length n, and the projection surface.

5. A method of tracing a drawing as defined in claim 4, wherein the specific projection drawing is substantially an isometric projection drawing.

6. A method of tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace a draft plan displayed on a display unit while displaying said draft plan said drawing being drawn by a specific projection drawing, said method comprising sequential steps including the following:

a step of designating a specific projection surface in said specific projection drawing;

a step of computing a length m0 of a long diameter of an ellipse E and a center point P0 of said long diameter corresponding to the center of said ellipse E based on a known ratio T between said length m0 of said long diameter and the distance between a pair of diagonal points Pq0 and Pq1 of rectangle R which is circumscribed around said ellipse E of said draft plan;

a step of computing a length m1 of a short diameter based on a known ratio S between the long diameter and the short diameter of an ellipse on said specific projection surface corresponding to a circle on a plane surface and also based on said length m0 of said long diameter; and

a step of generating vector data based on a direction D of the long diameter specified by said length m0 of said long diameter, said length m1 of said short diameter, said center point P0 of said long diameter, and said projection surface.

7. A method of tracing a drawing as defined in claim 6, wherein the specific projection drawing is substantially an isometric projection drawing.

8. An apparatus for tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace said draft plan shown on a display unit while displaying said draft plan read by an image scanner onto said display unit, comprising the following;

a mode-setting means 10 for setting a "four-point" mode for tracing an ellipse E of said draft plan from a pair of points Pi0 and Pi1 corresponding to both ends of a long diameter of said ellipse E and a pair of points Pj0 and Pj1 corresponding to both ends of a short diameter of said ellipse E of said draft plan;

an input means 20 for directly designating a pair of points Pi0 and Pi1 corresponding to both ends of said long diameter and a pair of points Pj0 and Pj1 corresponding to both ends of said short diameter of said ellipse E of said draft plan;

an arithmetic operation means 30 for computing a center point P0 of the long diameter corresponding to a length m0 of the long diameter, length m1 of the short diameter, a direction D and a center of said ellipse E of said draft plan based on said four points; and

a vector-data generating means 40 for generating vector data of said ellipse E base on said length m0 of the long diameter, said length m1 of the short diameter, said direction D, and said center point P0 of said long diameter of said ellipse E.

9. An apparatus for tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace said draft plan shown on a display unit by a specific projection drawing comprising the following:

a mode-setting means 10 for setting a two-point mode for tracing an ellipse E of said draft plan based on a specific projection surface in said specific projection drawing and a pair of points Pi0 and Pi1 corresponding to a long diameter of said ellipse E of said draft plan;

an input means 20 which is capable of designating a pair of points Pi0 and Pi1 corresponding to both ends of the long diameter of said ellipse E of said draft plan;

a memory means 31 which stores known data of the ratio s of the long and short diameters of an ellipse on a specific projection surface of said specific projection drawing corresponding to a circle on a plane surface and data of the direction D of said long diameter specified by the projection surface;

an arithmetic operation means 30 for computing length m0 of said long diameter and a center point P0 of said long diameter corresponding to the center of said ellipse E, wherein said arithmetic operation means 30 also computes a length m1 of a short diameter based on said ratio S of the long and short diameters and said length m0 of the long diameter stored in said memory means 31; and

a vector-data generating means 40 for generating vector data of said ellipse E based on said length m0 and m1 of said long and short diameters, the direction D, and center point P0 of said long diameter of said ellipse E of said draft plan.

10. An apparatus for tracing a drawing as defined in claim 9, wherein said specific projection drawing is substantially an isometric projection drawing.

11. An apparatus for tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace said draft plan shown on a display unit by a specific projection drawing comprising the following:

a mode-setting means 10 for setting "two-points of a reference direction" mode for tracing an ellipse E of said draft plan based on a specific projection surface in said specific projection drawing and a pair of points Pk0 and Pk1 corresponding to intersecting points of said ellipse E and a straight line L which is a reference direction in said projection drawing and passes through the center of said ellipse E of said draft plan;

an input means 20 which is capable of designating said pair of intersecting points Pk0 and Pk1 of said ellipse E of said draft plan;

a memory means 31 which stores data of a ratio of U of said length n between Pk0 and Pk1 and said length m0 of a long diameter and ratio V of said length n and said length m1 of a short diameter, of an ellipse E on a specific projection surface, and a data of a direction D of the long diameter specified by said projection surface;

an arithmetic operation means 30 for computing a center point P0 of the length n corresponding to the center of said ellipse E, wherein said arithmetic operation means also computes the length of m0 of the long diameter and the length of m1 of the short diameter based on the length n and said ratio of U and V stored in said memory means 31; and

a vector-data generating means 40 for generating vector data of said ellipse E based on said length m0 of the long diameter, said length m1 of the short diameter, the direction D, and the center point P0 of said length n between Pk0 and Pk1 of ellipse E of said draft plan.

12. An apparatus for tracing a drawing as defined in claim 11, wherein the specific projection drawing is substantially an isometric projection drawing.

13. An apparatus for tracing a drawing, which generates vector data corresponding to a draft plan by activating a drawing function to trace said draft plan shown on a display unit by a specific projection drawing comprising the following:

a mode-setting means 10 for setting "diagonal-points" mode for tracing an ellipse E of said draft plan based on a specific projection surface in said specific projection drawing and a pair of diagonal points Pq0 and Pq1 of a rectangle R which is circumscribed around said ellipse E of said draft plan;

an input means 20 which is capable of designating a pair of diagonal points Pq0 and Pq1 of said rectangle R circumscribed around said ellipse E of said draft plan;

a memory means 32 which stores data of a known ratio S of long and short diameters of an ellipse E on the specific projection surface corresponding to a circle on a plane surface, data of direction D of a long diameter specified by said projection surface and data of a known ratio T between said pair of diagonal points Pq0 and Pq1 of said rectangle R circumscribed around said ellipse E of said draft plan and the long diameter of said ellipse E of said draft plan;

an arithmetic operation means 30 for computing a length m0 of the long diameter of said ellipse E and a center point P0 of the long diameter corresponding to the center of said ellipse E based on the distance between said two diagonal points Pq0 and Pq1 and a ratio T, wherein said arithmetic operation means 30 also computes a length m1 of a short diameter based on a ratio S between the long and short diameters and said length m1 of said long diameter of said ellipse E; and

a vector-data generating means 40 for generating vector data of said ellipse E based on said length m0 of the long diameter, said length m1 of the short diameter, the direction D, and the center point P0 of said long diameter of said ellipse E of said draft plan.

14. An apparatus for tracing a drawing as defined in claim 13, wherein the specific projection drawing is substantially an isometric projection drawing.

15. In an apparatus for tracing a cubic view of a draft plan ellipse from a draft plan containing a draft copy of said ellipse, said cubic view being created by forming a specific projection drawing of said cubic view, said apparatus comprising:

storage means for storing a known ratio of a long diameter of an ellipse which would be generated on a specific surface of said specific projection drawing from a circle on a plane surface and the short diameter, of the same ellipse, which would be so generated on the same specific surface;

input means for designating end points of the long diameter of said draft plan ellipse;

arithmetic means for computing the length of said long diameter of said draft plan ellipse from said designated end points and further computing the length of the short diameter of said draft plan ellipse by using said known ratio and said computed length of said long diameter.

16. The apparatus for tracing a cubic view as defined in claim 15, wherein said specific projection drawing is substantially an isometric projection drawings.

17. The apparatus for tracing a cubic view as defined in claim 15, further including means to generate vector data concerning said cubic view of said draft plan ellipse.

18. In an apparatus for tracing a cubic view of a draft plan ellipse from a draft plan containing a draft copy of said ellipse, said cubic view being created by forming a specific projection drawing of said cubic view, said apparatus comprising:

storage means for storing a first known ratio of a diameter of an ellipse which would be generated on a specific surface of said specific projection drawing from a circle on a plane surface and a short diameter of the same ellipse which would be so generated on the same specific surface and for storing a second known ratio of a length of a long diagonal of a rectangle, which circumscribes an ellipse and has its four sides each tangent to the same ellipse on said specific surface, and the length of the long diameter of said circumscribed ellipse;

input means for designating the end points of the long diagonal of a rectangle which circumscribes said draft plan ellipse and has its four sides each tangent to said draft plane ellipse;

arithmetic means for computing the length of said long diagonal of said rectangle circumscribing said draft plan ellipse from said designated end points and further computing the length of the long diameter of said draft plan ellipse by using said known second ratio and said computed length of said long diagonal and finally computing the length of the short diameter of said draft plan ellipse by using said first known ratio and the computed length of the long diameter of the draft plan ellipse.

19. The apparatus for tracing a cubic view as defined in claim 18, wherein said specific projection drawing is substantially an isometric projection drawing.

20. The apparatus for tracing a cubic view as defined in claim 18, further including means to generate vector data concerning said cubic view of said draft plan ellipse.