System and method for modeling a spheroid world database

• US 20040098236A1
• Filed: 07/18/2003
• Published: 05/20/2004
• Est. Priority Date: 07/19/2002
• Status: Active Grant

• Current Assignee: Rockwell Collins Simulation and Training Solutions, LLC (Rtx Corporation)
• Original Assignee: Evans & Sutherland Computer Corp. (Elevate Entertainment, Inc.)
• Inventors: Cosman, Michael A., Mayer, Neal L., Bennion, Heber B., Dawson, Robert C.
• Granted Patent: US 7,872,647 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• CPC Class Codes: G06T 17/05 Geographic models
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation

Abstract

A system and method is provided for modeling a world database that is a spheroid in a computer graphics simulation system. The method includes the operation of modeling the world database using a plurality of geodetic terrain gridposts. A further operation is creating a triangulated network mesh based on the geodetic terrain gridposts in real-time as a function of eye position. In addition, the triangulated network mesh is stored in geodetic coordinates. The triangulated network mesh is then rendered using geometry formed by the triangulated network mesh.

Claims

1. A method for modeling a world database that is a spheroid in a computer graphics simulation system, comprising the steps of:

modeling the world database using a plurality of geodetic terrain gridposts;

creating a triangulated network mesh based on the geodetic terrain gridposts in real-time as a function of eye position and the triangulated network mesh is stored in geodetic coordinates;

rendering the triangulated network mesh using geometry formed by the triangulated network mesh.

2. The method as in claim 1, further comprising the step of converting the triangulated network mesh that is created in real-time to Cartesian coordinates based on the eye position.

3. A method as in claim 1, further comprising reducing a terrain facet size of the triangulated network mesh as the latitude increases.

4. A method as in claim 1, further comprising the step of modeling polar caps as groups of polygons that are attached to the triangulated network for at least one polar latitude.

5. A method as in claim 4, further comprising the step of modeling polar caps that are approximately 500 to 1500 miles in diameter.

6. A method as in claim 1, further comprising the step of placing feature models that are modeled in Cartesian coordinates at geodetic coordinates in the world database.

7. The method as in claim 1, further comprising the step of rendering the triangulated network by applying lighting, shading, and texture to the triangulated network.

8. The method as in claim 3, further comprising the step of displaying the rendered triangulated network to a user.

9. A system for modeling a world database that is spheroid in a computer graphics simulation system, comprising:

a world database modeled with geodetic terrain gridposts; and

a triangulated network mesh that is created in real-time using the geodetic grid posts to form a renderable landscape geometry.

10. A system as in claim 9, further comprising an eye position that is used to convert the triangulated network in geodetic coordinates to Cartesian coordinates.

11. A system for modeling a world database that is a spheroid in a computer graphics simulation system, comprising:

a world database modeled with geodetic terrain gridposts;

a triangulated network mesh created from the geodetic terrain gridposts;

a localizing conversion module configured for converting the triangulated network to relative localized geodetic coordinates in real-time.

12. A system as in claim 11, further comprising polar caps that are modeled as groups of polygons and attached to the triangulated network at the polar latitudes.

13. A system as in claim 12, further comprising polar caps that are approximately 500 to 1500 miles in diameter.

14. A system as in claim 11, further comprising a terrain facet with reduced size for the triangulated network mesh as the latitude increases.

15. A system as in claim 11, further comprising feature models that are modeled in Cartesian coordinates and placed at geodetic coordinates in the world database.

16. A method for modeling a world database that is spheroid in a computer graphics simulation system, comprising the steps of:

modeling the world database using geodetic terrain gridposts;

creating a triangulated network mesh from the geodetic terrain gridposts;

converting the triangulated network mesh to localized relative geodetic coordinates in real-time; and

converting the localized relative geodetic triangulated network mesh to Cartesian coordinates in real-time.

17. A method as in claim 16, further comprising the step of reducing a terrain facet size in the triangulated network mesh as the latitude increases.

18. A method as in claim 16, further comprising the step of modeling polar caps as groups of polygons that are attached to the triangulated network at the polar latitudes.

19. A method as in claim 18, further comprising the step of modeling polar caps that are approximately 1000 miles in diameter.

20. A method as in claim 16, further comprising the step of placing feature models that are modeled in Cartesian coordinates at geodetic coordinates in the world database.

21. A system for modeling a world database that is a spheroid in a computer graphics simulation system, comprising:

a world database modeled with geodetic terrain gridposts;

a triangulated network mesh created from the geodetic terrain gridposts;

a localizing conversion module configured for converting the triangulated network mesh to relative localized geodetic coordinates in real-time.

22. A system as in claim 21, further comprising a terrain facet with reduced size for the triangulated network mesh as the latitude increases.

23. A system as in claim 21, further comprising polar caps that are modeled as groups of polygons and attached to the triangulated network at the polar latitudes.

24. A system as in claim 22, wherein the polar caps are approximately 500 to 1500 miles in diameter.

25. A system as in claim 21, further comprising feature models that are modeled in Cartesian coordinates and positioned in the database at geodetic coordinates.

26. A method for modeling a world database that is a spheroid in a computer graphics simulation system, comprising the steps of:

modeling the world database using a plurality of geodetic terrain gridposts;

creating a triangulated network mesh based on the geodetic terrain gridposts;

storing the triangulated network in geodetic coordinates;

storing the feature models in Cartesian coordinates;

attaching feature models to the triangulated network for the world database at geodetic coordinates; and

rendering the triangulated network and the attached feature models on top of geometry formed by the triangulated network.

27. A method as in claim 26, further comprising the step of placing feature models that are modeled in Cartesian coordinates at positions in the database which are geodetic coordinates.

28. A method as in claim 26, further comprising the step of reducing a terrain facet size of the triangulated network as the latitude increases.

29. A method as in claim 26, further comprising the step of reducing the themel size as the latitude increases.

30. A method as in claim 26, further comprising the step of modeling polar caps as groups of polygons that are attached to the triangulated network at the polar latitudes.

31. A method as in claim 30, further comprising the step of modeling polar caps that are approximately 1000 miles in diameter.

32. A method as in claim 26, further comprising the step of storing feature models in a feature model database in Cartesian coordinates and the feature model database stores feature locations in relation to the world database in geodetic coordinates.

33. A method as in claim 26, further comprising the step of modeling static models in Cartesian coordinates and locating the static models at geodetic coordinates.

34. A method as in claim 26, further comprising the step of modeling dynamic models in Cartesian coordinates and locating the dynamic models at geodetic coordinates.

35. A method as in claim 26, further comprising the step of selecting a feature model from the group feature models consisting of buildings, transportation features, foliage, and airfields.

36. A method as in claim 26, further comprising the step of storing global texture in geodetic coordinates.

37. A method as in claim 26, further comprising the step of storing height fields in geodetic coordinates.

38. A method as in claim 26, further comprising the step of storing themel fields in geodetic coordinates.

39. A system for modeling a spheroid world database in a computer graphics simulation system, comprising:

a world database modeled with geodetic terrain gridposts;

a triangulated network mesh using the geodetic gridposts and the triangulated network is stored in geodetic coordinates;

feature models that are connected to the world database at geodetic coordinates and stored in Cartesian coordinates.