System and method for composition of NURBS surfaces
AssigneeSiemens Product Lifecycle Management Software Inc.
InventorsJoerg Hanisch, Lian Fang, Show Wang
Life of this patent
Estimating the term…
Abstract
A system, method, and computer program for preserving design intent of a Non-Uniform Rational B-spline (NURBS) surface without representation of a parent surface, comprising representing an output surface having control points that is independent from a refinement of the surface; interpolating a base surface from the output surface; calculating a delta vector that is a difference between the output surface and the base surface; and transforming the delta vector based upon a local coordinate system of a normal vector and a tangent plane of the base surface and appropriate means and computer-readable instructions.
Claims19
A method for preserving design intent of a Non-Uniform Rational B-spline (NURBS) surface without representation of a parent surface, comprising:
- representing an output surface having control points that are independent from a refinement of said output surface, the output surface c defined by
- c
-
- (
- u
- ,
- v
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- =
- ∑
- i
- =
- 0
- I
- -
- 1
-
-
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- j
- =
- 0
- J
- -
- 1
-
-
- c
- i
- ,
- j
-
- N
- m
- ,
- i
- ,
- u
-
- (
- u
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-
- N
- n
- ,
- j
- ,
- v
-
- (
- v
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- ;
- interpolating a base surface from said output surface, the base surface b defined by
- b
-
- (
- u
- ,
- v
- )
- =
- ∑
- k
- =
- 0
- K
- -
- 1
-
-
- ∑
- l
- =
- 0
- L
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- b
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- l
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- r
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-
- N
- s
- ,
- t
- ,
- q
-
- (
- v
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- ;
- calculating a delta vector that is a difference between said output surface and said base surface;
- and
- transforming said delta vector based upon a local coordinate system of a normal vector and a tangent plane of said base surface to form a delta surface, wherein r>1, s>1, m>1, and n>1 are orders, p={pk}k=0K+r−1 and q={ql}l=0L+s−1 are knot sequences of b in a u-direction and a v-direction, respectively, Nr,k,p denotes the kth normalized B-spline of order r with respect to a knot sequence p, Ns,l,q denotes the k1th normalized B-spline of order s with respect to a knot sequence q, bk,lε3 denotes a (k,l)th control point, u={ui}i=0l+m−1 and v={vj}j=0j+s−1 are knot sequences of b in a u-direction and a v-direction, respectively.
A system for preserving design intent of a Non-Uniform Rational B-spline (NURBS) surface without representation of a parent surface, comprising:
- a computer system, wherein said computer system includes a memory, a processor, a user input device, and a display device;
- a computer generated geometric model stored in said memory of said computer system, wherein the geometric model is in a computer-aided design (CAD) format;
- and
- wherein the computer system is configured to:
- represent an output surface having control points that are independent from a refinement of said output surface, the output surface c defined by
- c
-
- (
- u
- ,
- v
- )
- =
- ∑
- i
- =
- 0
- I
- -
- 1
-
-
- ∑
- j
- =
- 0
- J
- -
- 1
-
-
- c
- i
- ,
- j
-
- N
- m
- ,
- i
- ,
- u
-
- (
- u
- )
-
- N
- n
- ,
- j
- ,
- v
-
- (
- v
- )
- ,
- interpolate a base surface from said output surface, the base surface b defined by
- b
-
- (
- u
- ,
- v
- )
- =
- ∑
- k
- =
- 0
- K
- -
- 1
-
-
- ∑
- l
- =
- 0
- L
- -
- 1
-
-
- b
- k
- ,
- l
-
- N
- r
- ,
- k
- ,
- p
-
- (
- u
- )
-
- N
- s
- ,
- t
- ,
- q
-
- (
- v
- )
- ,
- calculate a delta vector that is a difference between said output surface and said base surface, and
- transform said delta vector based upon a local coordinate system of a normal vector and a tangent plane of said base surface to form a delta surface, wherein r>1, s>1, m>1, and n>1 are orders, p={pk}k=0k+r−1 and q={ql}l=0L+s−1 are knot sequences of b in a u-direction and a v-direction, respectively, Nr,k,p denotes the kth normalized B-spline of order r with respect to a knot sequence p, Ns,l,q denotes the 1th normalized B-spline of order s with respect to a knot sequence q, bk,lε3 denotes a (k,l)th control point, u={ui}i=0 l+m−1 and v={vj}j=0J+s−1 are knot sequences of b in a u-direction and a v-direction, respectively.
A data processing system for preserving design intent of a Non-Uniform Rational B-spline (NURBS) surface without representation of a parent surface, comprising:
- a storage device storing program code;
- and
- a processor operably connected to the storage device, the processor configured to execute the program code to:
- represent an output surface having control points that are independent from a refinement of said output surface, the output surface c defined by
- c
-
- (
- u
- ,
- v
- )
- =
- ∑
- i
- =
- 0
- I
- -
- 1
-
-
- ∑
- j
- =
- 0
- J
- -
- 1
-
-
- c
- i
- ,
- j
-
- N
- m
- ,
- i
- ,
- u
-
- (
- u
- )
-
- N
- n
- ,
- j
- ,
- v
-
- (
- v
- )
- ;
- interpolate a base surface from said output surface, the base surface b defined by
- b
-
- (
- u
- ,
- v
- )
- =
- ∑
- k
- =
- 0
- K
- -
- 1
-
-
- ∑
- l
- =
- 0
- L
- -
- 1
-
-
- b
- k
- ,
- l
-
- N
- r
- ,
- k
- ,
- p
-
- (
- u
- )
-
- N
- s
- ,
- t
- ,
- q
-
- (
- v
- )
- ;
- calculate a delta vector that is a difference between said output surface and said base surface;
- and
- transform said delta vector based upon a local coordinate system of a normal vector and a tangent plane of said base surface to form a delta surface, wherein r>1, s>1, m>1, and n>1 are orders, p={pk}k=0K+r−1 and q={ql}l=0L+s−1 are knot sequences of b in a u-direction and a v-direction, respectively, Nr,k,p denotes the kth normalized B-spline of order r with respect to a knot sequence p, Ns,l,q denotes the 1th normalized B-spline of order s with respect to a knot sequence q, bk,lε3 denotes a (k,1)th control point, u={ui}i=0l+m−1 and v={vj}j=0J+s−1 are knot sequences of b in a u-direction and a v-direction, respectively.
A system for preserving design intent of a Non-Uniform Rational B-spline (NURBS) surface without representation of a parent surface, comprising:
- a computer system, wherein said computer system includes a memory, a processor, a user input device, and a display device;
- a computer generated geometric model stored in said memory of said computer system, wherein the geometric model is in a computer-aided design (CAD) format;
- and
- wherein the computer system is configured to identify the NURBS surface, wherein the NURBS surface is a child surface formed from modification of the parent surface in accordance with the design intent, modify coordinates of said child surface independent from said parent surface to form a modified child surface, and preserve said design intent of the NURBS surface using the modified child surface.
Dependencies are inferred from the claim text.