Method and apparatus for rendering a three-dimensional object with a plurality of dots

• US 5,422,988 A
• Filed: 06/25/1992
• Issued: 06/06/1995
• Est. Priority Date: 06/25/1992
• Status: Expired due to Term

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Koide, Akio
• Primary Examiner(s): Herndon, Heather R.
• Assistant Examiner(s): SMITH, MICHAEL
• Application Number:
  US07/904,356
• Time in Patent Office: 1,076 Days
• Field of Search: 395/125, 395/123, 395/121, 395/120, 395/119, 395/126, 395/127, 395/128, 395/129, 340/727
• US Class Current: 345/419
• CPC Class Codes: G06T 15/205 Image-based rendering

Abstract

To render a three-dimensional object by using a plurality of dots, surfaces forming the three-dimensional object are divided into several regions based on curvature of the surfaces forming the object. A plurality of dots are arranged on the surfaces forming the object in accordance with rules which are different with respect to the different regions. To render a sphere by using a plurality of dots, spherical surfaces of the sphere are divided into polar regions and the equatorial region. In polar regions, dots whose number increase in accordance with radius around the axis of revolution are distributed at an equal interval on coaxial circumferences on polar regions. In the equatorial region, a certain number of dots are distributed at an equal interval on coaxial circumferences on the equatorial region so that a dot on the circumference are placed between dots on adjacent circumferences in the equatorial region.

Claims

1. A method of rendering on a display means a three dimensional body of revolution having a surface and an axis of revolution comprising the steps of:

a) selecting a portion of the surface of said three dimensional body of revolution as a first region and another portion of the surface as a second region;

b) arranging a location of a first plurality of dots on said first region based on a change in a radius of revolution of the surface of the first region about the axis of revolution;

c) arranging a location of a second plurality of dots on said second region not based on a change in the radius of revolution of the surface of the second region about the axis of revolution; and

d) rendering a selected portion of said first and second plurality of dots on said display means.

2. The method of claim 1 wherein said step of selecting includes selecting said regions based on a change in a radius of revolution of the surface from the revolution axis.

3. The method of claim 2 wherein said step of selecting includes selecting noncontiguous portions of the surface for at least one of said first and second regions.

4. The method of claim 2 wherein said step of selecting includes selecting said first and second regions based on a change in the radius of revolution, said first region having a larger change in the radius of revolution than said second region.

5. The method of claim 4 wherein said step of arranging a location of a first plurality of dots includes arranging an increasing number of dots in circles at approximately equal intervals about said revolution axis, said number of dots increasing with an increase in the radius of revolution.

6. the method of claim 5 wherein said step of arranging a location of a second plurality of dots includes arranging a equal number of dots in circles at approximately equal intervals about said revolution axis.

7. An apparatus for rendering a three dimensional body of revolution having a surface and an axis of revolution comprising:

a) means for selecting a portion of the surface of said three dimensional body of revolution as a first region and another portion of the surface as a second region;

b) means for arranging a location of a first plurality of dots on said first region based on a change in a radius of revolution of the surface of the first region about the axis of revolution; and

c) means for arranging a location of a second plurality of dots on said second region not based on a change in a radius of revolution of the surface of the second region about the axis of revolution.

8. The apparatus of claim 7 wherein said means for selecting includes means for selecting said regions based on a change in a radius of revolution of the surface from the revolution axis.

9. The apparatus of claim 8 wherein said means for selecting includes means for selecting noncontiguous portions of the surface for at least one of said first and second regions.

10. The apparatus of claim 8 wherein said means for selecting includes means for selecting said first and second regions based on a change in the radius of revolution, said first region having a larger change in the radius of revolution than said second region.

11. The apparatus of claim 10 wherein said means for arranging a location of a first plurality of dots includes means for arranging an increasing number of dots in circles at approximately equal intervals about said revolution axis, said number of dots increasing with an increase in the radius of revolution.

12. The apparatus of claim 11 wherein said means for arranging a location of a second plurality of dots includes means for arranging a equal number of dots in circles at approximately equal intervals about said revolution axis.

13. A computer system for rendering a three dimensional body of revolution having a surface and an axis of revolution comprising:

a) a processor for processing data;

b) a memory coupled to said processor for storing data to be processed;

c) means coupled to said processing means for selecting a portion of the surface of said body of revolution as a first region and another portion of the surface as a second region;

d) means coupled to said processing means for arranging a location of a first plurality of dots on said first region based on a change in the radius of revolution of the surface of the first region about the axis of revolution; and

e) means coupled to said processing means for arranging a location of a second plurality of dots on said second region not based on a change in the radius of revolution of the surface of the second region about the axis of revolution.

14. The computer system of claim 13 wherein said means for selecting includes means for selecting said regions based on a change in a radius of revolution of the surface from the revolution axis.

15. The computer system of claim 14 wherein said means for selecting includes means for selecting noncontiguous portions of the surface for at least one of said first and second regions.

16. The computer system of claim 14 wherein said means for selecting includes means for selecting said first and second regions based on a change in the radius of revolution, said first region having a larger change in the radius of revolution than said second region.

17. The computer system of claim 16 wherein said means for arranging a location of a first plurality of dots includes means for arranging an increasing number of dots in circles at approximately equal intervals about said revolution axis, said number of dots increasing with an increase in the radius of revolution.

18. The computer system of claim 17 wherein said means for arranging a location of a second plurality of dots includes means for arranging a equal number of dots in circles at approximately equal intervals about said revolution axis.