Methods and apparatus for production of three-dimensional objects by stereolithography

• US 5,059,359 A
• Filed: 04/18/1988
• Issued: 10/22/1991
• Est. Priority Date: 04/18/1988
• Status: Expired due to Term

• Current Assignee: 3D Systems, Inc. (3D Systems Corporation)
• Original Assignee: 3D Systems (3D Systems Corporation)
• Inventors: Harlow, Richard A., Albert, David J., Steinbaugh, Phil, Smalley, Dennis R., Hull, Charles W., Lewis, Charles W., Tarnoff, Harry L., Spence, Stuart T., Nguyen, Hop D., Remba, David Z., Vorgitch, Tom J.
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US07/182,830
• Time in Patent Office: 1,282 Days
• Field of Search: 264/22, 264/40.1, 264/255, 264/298, 264/308, 264/236, 264/347, 425/135, 425/150, 425/174.4, 425/404, 425/445, 364/474.05, 364/474.24, 364/476, 364/522, 365/107, 365/119, 365/120, 365/127, 156/64, 156/272.8, 156/273.3, 156/273.5, 156/275.5, 156/307.1, 156/378, 156/379.6, 427/8, 427/53.1, 427/54.1, 427/430.1, 118/402, 118/403, 118/428, 118/429, 118/620, 118/712, 250/492.1
• US Class Current: 264/401
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B29C 64/40 Structures for supporting 3D objects during manufacture and intended to be sacrificed after completion thereof
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 40/00 Auxiliary operations or equipment, e.g. for material handling
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: G01J 1/4257 applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam monitoring arrangements for lasers in general H01S3/0014
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G03F 7/70416 2.5D lithography
• CPC Class Codes: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: G06T 17/00 Three dimensional [3D] modelling, e.g. data description of 3D objects
• CPC Class Codes: G06T 17/10 Constructive solid geometry [CSG] using solid primitives, e.g. cylinders, cubes
• CPC Class Codes: G06T 17/20 Finite element generation, e.g. wire-frame surface description, tesselation

Abstract

An improved sterolithography system for generating a three-dimensional object by creating a cross-sectional pattern of the object to be formed at a selected surface of a fluid medium capable of altering its physical state in response to appropriate synergistic stimulation by impinging radiation, particle bombardment or chemical reaction, information defining the object being specially processed to reduce curl and distortion, and increase resolution, strength, accuracy, speed and economy of reproduction even for rather difficult object shapes, and successive adjacent laminae, representing corresponding successive adjacent cross-sections of the object, being automatically formed and integrated together to provide a step-wise laminar buildup of the desired object, whereby a three-dimensional object is formed and drawn from a substantially planar surface of the fluid medium during the forming process.

Claims

1. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to process data descriptive of said three-dimensional object comprised of at least some polygons having vertices, the polygons substantially spanning a surface of the object, by overlaying the descriptive data with a plurality of slicing planes spaced along a slicing axis, placing at least some of the polygon vertices to at least one of the slicing planes to obtain preliminary descriptive data, and then converting the preliminary descriptive data to data descriptive of object cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

2. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to process data descriptive of said three-dimensional object comprised of at least some polygons having vertices, the polygons substantially spanning a surface of the object, by overlaying the descriptive data with a plurality of slicing planes spaced along a slicing axis, placing at least some of the polygon vertices to at least one of the slicing planes to obtain preliminary descriptive data, and then converting the preliminary descriptive data to data descriptive of object cross-sections, said data descriptive of said cross-sections being created, at least in part, from the preliminary descriptive data at planes offset from the slicing planes; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

3. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of object cross-sections, by overlaying the object descriptive data with a plurality of slicing levels spaced along a slicing axis, and generating near-flat skin data on a cross-section from the object descriptive data at more than one of said slicing levels; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

4. The system of claim 3 wherein said at least one computer is programmed to form said near-flat skin data which is up facing near-flat skin data.

5. The system of claim 3 wherein said at least one computer is programmed to form said near-flat skin data which is down-facing near-flat skin data.

6. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data representative of cross-sections of the object, the data representative of said cross-sections specifying, at least in part, lines of solidified material on a cross-section which leave areas of substantially unsolidified material on that cross-section; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

7. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into preliminary data descriptive of cross-sections of the object specifying, at least in part, lines of solidified material having a width, and to modify at least some of the preliminary data in order to offset at least some of the lines to at least partially compensate for the width of the lines to obtain data descriptive of said cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

8. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, with a first exposure specified for the first block of lines which is different from a second exposure specified for the second block of lines; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

18. The system of claim 8

wherein said at least one computer is programmed to convert said data descriptive of the object to said data descriptive of object cross-sections, including generating cross-hatch data specifying forming said first block of lines of solidified material on a cross-section at said first exposure, and generating skin data specifying forming said second block of lines of solidified material at said second exposure different from the first exposure on that same cross-section.

47. The system of claim 8 wherein said at least one computer is programmed to convert said data descriptive of the object to said data descriptive of object cross-sections, including generating at least some boundary data specifying forming said first block of lines of solidified material on a cross-section at said first exposure, and generating skin data specifying forming said second block of lines of solidified material on the cross-section at said second exposure different from the first exposure.

9. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of a faceted representation of the object into data descriptive of object cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

10. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of said three-dimensional object comprised of at least some polygons having vertices, the polygons substantially spanning a surface of the object;

processing said object descriptive data by overlaying the object descriptive data with a plurality of slicing planes spaced along a slicing axis, and placing at least some of the polygon vertices to at least one of the slicing planes to obtain preliminary object descriptive data;

converting the preliminary object descriptive data to data representative of object cross-sections; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

11. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of said three-dimensional object comprised of at least some polygons having vertices, the polygons substantially spanning a surface of the object;

processing said descriptive data by overlying said data with a plurality of slicing planes spaced along a slicing axis, and placing at least some of the polygon vertices to at least one of the slicing planes to obtain preliminary object descriptive data;

converting the preliminary object descriptive data to data representative of object cross-sections, the data representative of said cross-sections being created, at least in part, from the object descriptive data at planes offset from the slicing planes; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

12. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the three-dimensional object;

converting the object descriptive data into data representative of object cross-sections by overlaying the object descriptive data with a plurality of slicing levels spaced along a slicing axis, and generating near-flat skin data for a cross-section from said object descriptive data at more than one of said slicing levels; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

13. The method of claim 12, wherein the converting step further comprises generating said near-flat data which is up-facing near-flat data.

14. The method of claim 12, wherein the converting step further comprises generating said near-flat data which is down-facing near-flat data.

15. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the three-dimensional object;

converting the data descriptive of the object into preliminary data descriptive of cross-sections of the object, the preliminary data descriptive of said cross-sections specifying lines of solidified material having a width;

modifying at least some of the data to offset at least some of the lines to at least partially compensate for the width of the lines to obtain data descriptive of said cross-sections; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object substantially cross-section by cross-section.

16. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the three-dimensional object;

converting the data descriptive of the object to data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, with a first exposure specified for the first block of lines which is different from a second exposure specified for the second block of lines; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

46. The method of claim 16 further comprising converting the data descriptive of the object to said data descriptive of object cross-sections, including generating cross-hatch data specifying forming said first block of lines of solidified material on a cross-section at said first exposure, and forming said second block of lines of solidified material on the same cross-section at said second exposure different from the first exposure.

48. The method of claim 16 further comprising converting the data descriptive of the object to said data descriptive of object cross-sections, including generating at least some boundary data specifying forming said first block of lines of solidified material on a cross-section at said first exposure, and generating skin data specifying said second block of lines of solidified material on the cross-section at said second exposure different from the first exposure.

17. A method for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of a faceted representation of the object;

converting the object descriptive data to data descriptive of object cross-sections; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

19. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, said system comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of object cross-sections by generating data descriptive of a boundary of a cross-section, and boundary orientation information, and generating skin data, specifying lines of solidified material within the boundary of that cross-section, at least in part, from the data descriptive of the boundary and the boundary orientation information; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

20. The system of claim 19 wherein said at least one computer generates said skin data which is flat skin data.

21. The system of claim 19 wherein said at least one computer generates said skin data which is near-flat skin data.

22. The system of claim 19 wherein said at least one computer generates said skin data which is up-facing skin data.

23. The system of claim 19 wherein said at least one computer generates said skin data which is down-facing skin data.

24. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, said system comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of object cross-sections including generating data descriptive of a boundary of a cross-section, and boundary orientation information, and then generating cross-hatch data, specifying lines of solidified material within the boundary of that same cross-section, at least in part, from the data descriptive of the boundary and the boundary orientation information; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

25. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, said system comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, and specifying a spacing between the lines in the first block which is different from a spacing between the lines in the second block; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

56. The system of claim 25 wherein said at least one computer is programmed to convert said data descriptive of the object to said data representative of cross-sections of the object including generating cross-hatch data specifying said first block of lines of solidified material on a cross-section, and skin data specifying said second block of lines of solidified, material on that cross-section.

26. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, said system comprising:

at least one computer including a CAD computer, programmed to convert data descriptive of the object, generated on the CAD computer, to data descriptive of a faceted representation of the object, and to convert the data descriptive of the faceted representation to data descriptive of object cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

27. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon selective exposure to synergistic stimulation, comprising:

at least one computer programmed to convert a descriptive representation of the object to representations of object cross-sections, the representations of said cross-sections specifying a surface comprised of substantially transformed material enclosing at least some material that is not substantially transformed in an area specified to be solid by the descriptive representation; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said representations of said cross-sections to form said object cross-section by cross-section.

28. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon selective exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data representative of object cross-sections by first generating preliminary cross-sectional data from the data descriptive of the object located at spaced splicing planes, and then adding at least some near-flat data to the preliminary cross-sectional data to form said data representative of said cross-sections, which specifies an object which is substantially uniformly oversized compared to the object described by the object descriptive data; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

29. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon selective exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data representative of object cross-sections by first generating preliminary cross-sectional data from the object descriptive data located at spaced slicing planes, and the removing at least some near-flat data from the preliminary cross-sectional data to form said data representative of said cross-sections which specifies an object which is substantially uniformly undersized compared to the object specified by the object descriptive data; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

30. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon selective exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data representative of a number of object cross-sections, which are situated between an up-facing feature of the object spaced from a down-facing feature of the object by a distance, by utilizing a number of slicing planes spaced along a slicing axis between the up and down-facing features, which planes substantially span the distance between the up- and down-facing features, wherein the number of cross-sections is one less than the number of slicing planes; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

31. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon selective exposure to synergistic stimulation, comprising:

providing data descriptive of the object;

utilizing a number of slicing planes, spaced along a slicing axis between an up-facing feature of the object and a down-facing feature of the object spaced by a distance from the up-facing feature, which planes substantially span the distance between the up- and down-facing features, to convert the data descriptive of the object into data representative of a number of object cross-sections situated between the up- and down-facing features, wherein the number of cross-sections is one less than the number of slicing planes; and

selective exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

32. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object;

converting the data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, and specifying a spacing between the lines of the first block which is different from a spacing between the lines of the second block; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

57. The method of claim 32 further comprising converting the object descriptive data into said data descriptive of object cross-sections, including generating cross-hatch data specifying said first block of lines of solidified material on a cross-section and generating skin data specifying said second block of lines of solidified material on that cross-section.

33. A system for forming three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, the lines in the first block specified to be exposed before the lines on the second block; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

39. The system of claim 33 wherein said at least one computer is programmed to convert said data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming boundary lines of solidified material on a cross-section prior to forming hatch lines of solidified material on the cross-section.

41. The system of claim 33 wherein said at least one computer is programmed to convert said data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming boundary lines of solidified material on a cross-section prior to forming skin lines of solidified material on the cross-section.

43. The system of claim 33 wherein said at least one computer is programmed to convert said data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming hatch lines of solidified material on a cross-section prior to forming skin lines of solidified material on the cross-section.

34. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object;

converting the data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying first and second blocks of lines of solidified material on a cross-section, the lines in the first block specified to be exposed before the lines in the second block; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

40. The method of claim 34 further comprising converting said data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming boundary lines of solidified material on a cross-section prior to forming hatch lines of solidified material on the cross-section.

42. The method of claim 34 further comprising converting the data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming boundary lines of solidified material on a cross-section prior to forming skin lines of solidified material on the cross-section.

44. The method of claim 34 further comprising converting the data descriptive of the object into said data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying forming hatch lines of solidified material on a cross-section prior to forming skin lines of solidified material on the cross-section.

35. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying a first block of lines of solidified material on a cross-section generated from a first boundary, and a second block of lines of solidified material on the cross-section generated from a second boundary; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

36. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object;

converting the data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying a first block of lines of solidified material on a cross-section generated from a first boundary, and a second block of lines of solidified material on the cross-section generated from a second boundary; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

37. A system for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying a first boundary on a cross-section generated from the data descriptive of the object located at at least one slicing plane, and specifying a second boundary on the cross-section generated from the data descriptive of the object located at at least one different slicing plane; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

38. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object;

converting the data descriptive of the object into data descriptive of cross-sections of the object, the data descriptive of said cross-sections specifying a first boundary on a cross-section generated from the data descriptive of the object located at at least one slicing plane, and specifying a second boundary on the cross-section generated from the data descriptive of the object located at at least one different slicing plane; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

45. A method for forming a three-dimensional object cross-section by cross-section out of a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object;

converting the data descriptive of the object to data descriptive of object cross-sections including generating data descriptive of a boundary on a cross-section, and boundary orientation information, and then generating cross-hatch data specifying lines of solidified material within the boundary at least in part from the data descriptive of the boundary and the boundary orientation information; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data representative of said cross-sections to form said object cross-section by cross-section.

49. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, said system comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of object cross-sections, including generating at least some boundary data specifying forming a first block of lines of solidified material on a cross-section, and generating cross-hatch data specifying forming a second block of lines of solidified material on the same cross-section which leaves areas of substantially unsolidified material on that cross-section; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said cross-sectional data to form said object cross-section by cross-section.

50. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of object cross-sections, including generating preliminary cross-sectional data specifying lines of solidified material on the cross-sections, and removing any of said preliminary data specifying duplicate lines of solidified material on the cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

51. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of object cross-sections, said data descriptive of said cross-sections specifying over-curing at least some regions on a cross-section that overlay regions on a previous cross-section to insure adhesion between these cross-sections; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

52. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of the object to data descriptive of object cross-sections, including generating preliminary data specifying lines of solidified material on the cross-sections, and ordering the preliminary data to reduce jumping distance of said beam of said synergistic stimulation; and

means for selectively exposing layers of said material to said beam of said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

53. A method for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of the object generated on a CAD computer;

converting the data descriptive of the object to data descriptive of a faceted representation of the object;

converting the data descriptive of the faceted representation of data descriptive of object cross-sections; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

54. A system for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising:

at least one computer programmed to convert data descriptive of a faceted representation of the object, the faceted representation comprising a plurality of facets substantially spanning a surface of the object, including specified facets having slopes with respect to the surface, to data descriptive of cross-sections of the object utilizing at least in part information representative of the slopes; and

means for selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.

55. A method for forming a three-dimensional object cross-section by cross-section from a material capable of selective physical transformation upon exposure to synergistic stimulation, comprising the steps of:

providing data descriptive of a faceted representation of the object, the faceted representation comprising a plurality of facets substantially spanning a surface of the object, including specified facets having slopes relative to the surface of the object, to data descriptive of object cross-sections utilizing at least in part information representative of said slopes; and

selectively exposing layers of said material to said synergistic stimulation in accordance with said data descriptive of said cross-sections to form said object cross-section by cross-section.