US3889107A
Expired / Lapsed
US
⏱️ 0.0 years remaining
System of polygon sorting by dissection
Assignee: Evans and Sutherland Computer Corp
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Filing: 1973-09-27
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Granted: 1975-06-10
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Expires: 1993-09-27
Abstract
Abstract A polygon-dissection structure is disclosed incorporated in a system for processing geometric data, e.g. data representing three-dimensional polygons, as by subdividing such polygons to accomplish sorting of the data. The system operates to divide a working volume, e.g. a perspective pyramid, into successivelysmaller subvolumes. The separating planes are placed at arbitrary angles to coincide with the edges and surfaces of polygons that define objects to be represented. Polygons which straddle separating planes are dissected into two parts which are thereafter treated separately. Dissection by the system results in simplification in accounting for the polygons in relation to specific subvolumes. The system can be applied to the detection of those polygons which hide others thereby enabling a solution to the hidden-surface problem. Additionally, the system affords a simple mechanism for resolving shadowed portions of polygons as well as portions of polygons obstructed by semi-transparent surfaces and for explicitly computing and displaying implied lines of intersections existing between two inter-penetrating polygons. Alternatively, the system provides an efficient way of detecting if any or a multiplicity of polyhedra solids interpenetrate.
Inventors
- 👤 Ivan E Sutherland
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:37
CPC Classifications
G; G09; G09G; G09G1/00; G09G1/06; G06; G06T; G06T15/00; G06T15/10; G06T15/40; G06T15/405
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
A method for processing data in relation to a volume of space comprising the steps of: representing data in the form of electrical signals manifesting objects and positional relationships of said objects in said volume of space; defining a selected viewpoint in relation to said volume of space; selectively definiNg a specific plane in terms of electrical signals, from various possible planes lying in said volume of space, said specific plane being related to one of said objects, said possible planes including planes extending transverse to the axis of said selected viewpoint; and testing said electrical signals manifesting objects and positional relationships of said objects in said volume of space in relation to said specific plane to generate signals that are definitive of data representing said objects on each side of said specific plane.
Claim 2
Independent Claim
134 words
A method for processing data in relation to a volume of space comprising the steps of: representing data in the form of electrical signals manifesting objects and positional relationships of said objects in said volume of space; defining a selected viewpoint in relation to said volume of space; selectively definiNg a specific plane in terms of electrical signals, from various possible planes lying in said volume of space, said specific plane being related to one of said objects, said possible planes including planes extending transverse to the axis of said selected viewpoint; and testing said electrical signals manifesting objects and positional relationships of said objects in said volume of space in relation to said specific plane to generate signals that are definitive of data representing said objects on each side of said specific plane.
Claim 3
Dependent Claim
26 words
A method wherein each of the steps of claim 1 is progressively repeated in sequence to provide display electrical signals defining select portions of said objects.
Claim 4
Dependent Claim
15 words
A method according to claim 1 wherein said electrical signals represent vertex locations defining polygons.
Claim 5
Dependent Claim
25 words
A method according to claim 1 wherein said plane in said volume of space is defined coincident with an edge of one of said objects.
Claim 6
Dependent Claim
45 words
A method according to claim 4 further including the steps of: representing the opacity of said objects with opacity electrical signals and modifying said signals definitive of data representing said objects on each side of said specific plane in accordance with said opacity electrical signals.
Claim 7
Dependent Claim
142 words
A data processing system comprising: means for providing sets of electrical signals representative of positional vertices definitive of polygons in space; first means for registering one set of said sets of electrical signals; second means for registering representations definitive of a plane in said space; processing means connected to receive signals from: said means for providing signals definitive of polygons in space, said first register means and said second register means, for processing said one set of electrical signals with another set of said sets of electrical signals provided from said means for providing, subsequent to said one set, to provide separate developed sets of electrical signals representative of vertices sorted with respect to said plane in said space, said processing means including a pair of output means for individually receiving said signals representative of vertices sorted with respect to said plane.
Claim 8
Dependent Claim
142 words
A data processing system comprising: means for providing sets of electrical signals representative of positional vertices definitive of polygons in space; first means for registering one set of said sets of electrical signals; second means for registering representations definitive of a plane in said space; processing means connected to receive signals from: said means for providing signals definitive of polygons in space, said first register means and said second register means, for processing said one set of electrical signals with another set of said sets of electrical signals provided from said means for providing, subsequent to said one set, to provide separate developed sets of electrical signals representative of vertices sorted with respect to said plane in said space, said processing means including a pair of output means for individually receiving said signals representative of vertices sorted with respect to said plane.
Claim 9
Dependent Claim
30 words
A system according to claim 6 and further including selection means to specify a series of said representations definitive of planes to define progressively smaller volumes for said positional vertices.
Claim 10
Dependent Claim
30 words
A system according to claim 7 further including means for detecting coincidence of a boundary of one of said volumes and one of said polygons for controlling said selection means.
Claim 11
Dependent Claim
30 words
A system according to claim 8 wherein said first register means includes means to register signals indicating that one of said polygons is definitive of a silhouette of an object.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-09 | 1978-12-09 | 1979-06-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-09 | 1982-12-09 | 1983-06-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-09 | 1986-12-09 | 1987-06-10 | $7700.00 | Window Closed / Lapsed |