Conversion of data for two or three dimensional geometric entities

1. A computer-implemented method comprising:

in a running graphics application program, receiving a sequence of function calls from a computer-assisted design (CAD) program to one or more drawing functions, the drawing functions implementing an application program interface (API) for generating graphical output on a two-dimensional medium, wherein the drawing functions are implemented in a library substitute for an original library implementing the API;

in response to each function call, determining in an automatic manner without human intervention if the function call is one of one or more predetermined kinds of function calls, and if it is then:

if the function call is of a kind that passes point data, adding the point data to a data structure,

if the function call is of a kind that passes entity data, adding the entity data to the data structure, and

if the function call is of a kind that indicates an end condition, exporting the data in the data structure to one or more text export files and clearing the data structure of the data so that the data is not exported a second time;

after receiving the last of the sequence of function calls, closing the one or more export files;

wherein the sequence of function calls comprises two or more end condition function calls, so that exporting occurs two or more times in response to the two or more end condition function calls;

wherein the point data represents one or more vertices and the entity data represents one or more geometric entities; and

wherein the text export file is in a second format, the second format being different from a first format used by the CAD program, wherein the data structure comprises a plurality of tables, and the wherein the point data is added to a first table and the entity data is added to a second table.

2. The computer-implemented method of claim 1 , wherein the one or more text export files are drawing exchange format (DXF) files.

3. The computer-implemented method of claim 1 , wherein the entity data include data identifying a triangle.

4. The computer-implemented method of claim 1 , wherein the entity data include data identifying a quadrilateral.

5. The computer-implemented method of claim 1 , wherein the entity data include data identifying a normal vector to a surface.

6. The computer-implemented method of claim 1 , wherein the entity data includes color information.

7. The computer-implemented method of claim 1 , wherein the entity data includes surface texture information.

8. The computer-implemented method of claim 1 , wherein the entity data includes transparency information.

9. The computer-implemented method of claim 1 , wherein exporting the data includes recording the data in an external storage unit.

10. A computer program product, tangibly embodied on a computer-readable medium, comprising instructions operable to cause a computer to:

in a running graphics application program, receive a sequence of function calls from a computer-assisted design (CAD) program to one or more drawing functions, the drawing functions implementing a first application program interface (API) for generating graphical output on a two-dimensional medium, wherein the drawing functions comply with a second API and are implemented in a library substitute for a library implementing the second API;

in response to each function call, determine in an automatic manner without human intervention if the function call is one of one or more predetermined kinds of function calls, and if it is then:

if the function call is of a kind that passes point data, add the point data to a data structure,

if the function call is of a kind that passes entity data, add the entity data to the data structure, and

if the function call is of a kind that indicates an end condition, export the data in the data structure to one or more text export files and clearing the data structure so that the data is not exported a second time;

after receiving the last of the sequence of function calls, close the one or more export files;

wherein the sequence of function calls comprises two or more end condition function calls, so that exporting occurs two or more times in response to the two or more end condition function calls;

wherein the point data represents one or more vertices and the entity data represents one or more geometric entities; and

wherein the text export file is in a second format, the second format being different from a first format used by the CAD program, wherein the data structure comprises a plurality of tables, and the wherein the point data is added to a first table and the entity data is added to a second table.

11. The computer program product of claim 10 , wherein the one or more text export files are drawing exchange format (DXF) files.

12. The computer program product of claim 10 , wherein the entity data include data identifying a triangle.

13. The computer program product of claim 10 , wherein the entity data include data identifying a quadrilateral.

14. The computer program product of claim 10 , wherein the entity data include data identifying a normal vector to a surface.

15. The computer program product of claim 10 , wherein the entity data includes color information.

16. The computer program product of claim 10 , wherein the entity data includes surface texture information.

17. The computer program product of claim 10 , wherein the entity data includes transparency information.

18. The computer program product of claim 10 , wherein exporting the data includes recording the data in an external storage unit.