Nature Simulation Systems Inc. v. Autodesk, Inc. ( 2022 )


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  • Case: 20-2257   Document: 31     Page: 1    Filed: 01/27/2022
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    NATURE SIMULATION SYSTEMS INC.,
    Plaintiff-Appellant
    v.
    AUTODESK, INC.,
    Defendant-Appellee
    ______________________
    2020-2257
    ______________________
    Appeal from the United States District Court for the
    Northern District of California in No. 3:19-cv-03192-SK,
    Magistrate Judge Sallie Kim.
    ______________________
    Decided: January 27, 2022
    ______________________
    MATTHEW MICHAEL WAWRZYN, Wawrzyn LLC, Chi-
    cago, IL, argued for plaintiff-appellant.
    BRIAN ROBERT MATSUI, Morrison & Foerster LLP,
    Washington, DC, argued for defendant-appellee. Also rep-
    resented by SETH W. LLOYD; RUDOLPH KIM, ROMAN A.
    SWOOPES, Palo Alto, CA.
    ______________________
    Case: 20-2257      Document: 31     Page: 2    Filed: 01/27/2022
    2           NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.
    Before NEWMAN, LOURIE, and DYK, Circuit Judges.
    Opinion for the court filed by Circuit Judge NEWMAN.
    Dissenting opinion filed by Circuit Judge DYK.
    NEWMAN, Circuit Judge.
    Nature Simulation Systems, Inc. (“NSS”) is the owner
    of United States Patents No. 10,120,961 (“the ’961 patent”)
    and No. 10,109,105 (“the ’105 patent”), both entitled
    “Method for Immediate Boolean Operations Using Geomet-
    ric Facets.” The patents relate to methods of packaging
    computer-aided data for three-dimensional objects. 1
    NSS brought suit for infringement against Autodesk,
    Inc. in the United States District Court for the Northern
    District of California. At issue are claims 1 and 8 of the
    ’961 patent and claim 1 of the ’105 patent. The district
    court held a claim construction (Markman) hearing, and
    ruled the claims invalid on the ground of claim indefinite-
    ness, 
    35 U.S.C. § 112
    (b). 2 That decision is the subject of
    this appeal.
    We conclude that the district court erred on the legal
    standard for claim indefiniteness, and that on the correct
    standard the claims are not indefinite. The decision of in-
    validity on this ground is reversed.
    1   The ’961 patent is a continuation-in-part of the ’105
    patent, and the specifications and claims do not materially
    differ with respect to the issues of this appeal; thus the par-
    ties and this court generally cite to the ’961 patent.
    2  Nature Simulation Systems Inc. v. Autodesk, Inc.,
    No. 19-CV-03192-SK, ECF. No. 61, (N.D. Cal. July 31,
    2020) (“Dist. Ct. Op.”); Final Judgment, 
    2020 WL 5525170
    (N.D. Cal. Aug. 11, 2020).
    Case: 20-2257     Document: 31     Page: 3    Filed: 01/27/2022
    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.               3
    BACKGROUND
    Standards of review
    Claim construction is a question of law, and receives de
    novo review on appeal. Markman v. Westview Instruments,
    Inc., 
    517 U.S. 370
    , 390–91 (1996); Teva Pharms. USA Inc.
    v. Sandoz, Inc., 
    574 U.S. 318
    , 325 (2015). Claim indefinite-
    ness is a legal conclusion, in implementation of 
    35 U.S.C. § 112
    . See Atmel Corp. v. Info. Storage Devices, Inc., 
    198 F.3d 1374
    , 1378 (Fed. Cir. 1999) (“‘A determination of claim
    indefiniteness is a legal conclusion that is drawn from the
    court’s performance of its duty as the construer of patent
    claims.’ Indefiniteness, therefore, like claim construction,
    is a question of law that we review de novo.”) (quoting Per-
    sonalized Media Communications, LLC v. Int’l Trade
    Comm’n, 
    161 F.3d 696
    , 705 (Fed. Cir. 1998)).
    Claim indefiniteness is decided from the viewpoint of
    persons skilled in the field of the invention. Personalized
    Media, 161 F.3d at 705. The district court and the parties
    agreed that for the technology here at issue, such persons
    would have “at least a master’s degree in computer science
    or a related field, or a bachelor’s degree in computer science
    or a related field plus two years of relevant experience,
    with experience in computer graphics, computer-aided de-
    sign, solid modeling, or geometric modeling.” Dist. Ct. Op.
    at 7.
    United States patents are accompanied by a presump-
    tion of validity, 
    35 U.S.C. § 282
    , and invalidity must be es-
    tablished by clear and convincing evidence. Sonix Tech.
    Co. Ltd. v. Pubs. Int’l, Ltd., 
    844 F.3d 1370
    , 1377 (Fed. Cir.
    2017).
    The patented inventions
    The ’961 and ’105 patents are for a computer-imple-
    mented method for building three-dimensional objects em-
    ploying a computation method called “Boolean operation.”
    The patents introduce the invention as follows:
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    4          NATURE SIMULATION SYSTEMS INC.     v. AUTODESK, INC.
    This invention provides an immediate Boolean op-
    eration method for building three (3) dimensional
    geometric models from primary geometric objects
    to Computer Aided Design, Computer Graphics,
    Solid Modeling systems, and Surface Modeling sys-
    tems, which are widely used in product design,
    manufacturing, and simulation. Mechanic indus-
    try, culture and sports, everywhere there are geo-
    metric shapes, may have CAD/CG applications.
    ’961 patent, col.1, ll.7–14. The patents are for data struc-
    tures and algorithms for the claimed method, which is de-
    scribed as a modification of a known Boolean operation
    published in 1981 for analyzing and representing three-di-
    mensional geometric shapes (“the Watson method”). The
    district court states: “NSS concedes that the general idea
    of performing Boolean operations in this area was well
    known before the patents in dispute, as the asserted pa-
    tents cite to prior art disclosing this concept.” Dist. Ct. Op.
    at 2. The court summarized the prior art:
    There are two methods from prior art that are cited
    in the asserted patents. The Delaunay method is a
    known method of triangulation (known as the “De-
    launay triangulation”), and the Watson method is
    a known algorithm for computing a Delaunay tri-
    angulation that is described in a paper written in
    1981 by D.F. Watson.
    
    Id.
     (citing ’961 patent col.6 ll.64–66; ’105 patent col.6 ll.42–
    44). The patents state that the “modified Watson method”
    described therein provides simplicity and flexibility com-
    pared with prior methods, and is easier to program and im-
    plement. ’961 patent, col.1, ll.17–62. Both sides presented
    technology tutorials to the district court; the NSS tutorial
    was presented by inventor Shangwen Cao, and the Auto-
    desk tutorial was presented by expert Dr. Daniel Aliaga.
    At the Markman hearing, Autodesk requested con-
    struction of eight terms in the claims, and supported this
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    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.              5
    request with the Declaration of Dr. Aliaga. NSS argued
    that the challenged terms do not require construction, are
    clearly set forth in the specification, and should receive
    their ordinary meaning in this field of technology.
    The district court based its decision on two of the chal-
    lenged terms, shown in boldface in clauses [2] and [3] of
    Claim 1:
    1. A method that performs immediate Boolean op-
    erations using geometric facets of geometric objects
    implemented in a computer system and operating
    with a computer, the method comprising:
    [1] mapping rendering facets to extended
    triangles that contain neighbors;
    [2] building intersection lines starting with
    and ending with searching for the first pair
    of triangles that hold a start point of an in-
    tersection line by detecting whether two
    minimum bounding boxes overlap and per-
    forming edge-triangle intersection calcula-
    tions for locating an intersection point,
    then searching neighboring triangles
    of the last triangle pair that holds the
    last intersection point to extend the in-
    tersection line until the first intersection
    point is identical to the last intersection
    point of the intersection line ensuring that
    the intersection line gets closed or until all
    triangles are traversed;
    [3] splitting each triangle through which
    an intersection line passes using modified
    Watson method, wherein the modified
    Watson method includes removing dupli-
    cate intersection points, identifying posi-
    tions of end intersection points, and
    splitting portion of each triangle including
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    6          NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.
    an upper portion, a lower portion, and a
    middle portion;
    [4] checking each triangle whether it is ob-
    scure or visible for Boolean operations or
    for surface trimming;
    [5] regrouping facets in separate steps that
    includes copying triangles, deleting trian-
    gles, reversing the normal of each triangle
    of a geometric object, and merging reserved
    triangles to form one or more new extended
    triangle sets; and
    [6] mapping extended triangles to render-
    ing facets.
    ’961 patent, col.9, ll.17–48 (bracketed numbers and bold-
    face added).
    After the Markman hearing the district court ruled
    that these two claim terms are indefinite, rendering the
    claims invalid. The district court did not define the two
    terms; instead, the court held that a claim term is indefi-
    nite, as a matter of law, if there are any “unanswered ques-
    tions” about the term. The court referred to the conflict
    between the opinion of Autodesk’s expert, and the patent
    examiner’s resolution of indefiniteness, and stated:
    [T]he question is thus: if the PTO issues a patent
    after amendment to clarify an indefinite term, but
    an expert later opines that a POSITA would not un-
    derstand the term, how does the Court determine
    whether the term is indefinite? The only way to do
    so here is to look at each argument to see if Auto-
    desk raises any unanswered questions. Here, Au-
    todesk does.
    Dist. Ct. Op. at 8. The district court recited several “unan-
    swered questions,” and further stated that even if the ques-
    tions are answered in the specification, the definiteness
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    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.               7
    requirement is not met if the questions are not answered
    in the claims. Thus the court held the claims invalid under
    
    35 U.S.C. § 112
    .
    NSS states that the court applied incorrect legal stand-
    ards, and that on the correct law the claims are not indefi-
    nite.
    DISCUSSION
    Patent claims must provide reasonable certainty in de-
    fining what is patented, in conformity with the require-
    ments of 
    35 U.S.C. § 112
    . We start with the statute:
    
    35 U.S.C. § 112
    Section 112 states the required content of the patent
    document. Section 112(a) provides that the specification
    must describe the invention in full, clear, concise, and exact
    terms, as to enable its practice by any person skilled in the
    field of the invention, and must include the best mode
    known to the inventor:
    § 112. Specification
    (a) In General.-- The specification shall contain a
    written description of the invention, and of the
    manner and process of making and using it, in such
    full, clear, concise, and exact terms as to enable any
    person skilled in the art to which it pertains, or
    with which it is most nearly connected, to make
    and use the same, and shall set forth the best mode
    contemplated by the inventor or joint inventor of
    carrying out the invention.
    Section 112(b) requires that the specification conclude with
    claims that state the subject matter that is patented:
    (b) Conclusion.-- The specification shall conclude
    with one or more claims particularly pointing out
    and distinctly claiming the subject matter which
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    8          NATURE SIMULATION SYSTEMS INC.     v. AUTODESK, INC.
    the inventor or a joint inventor regards as the in-
    vention.
    The claims define the patent right, and perform the “no-
    tice” function of legal documents; thus precision and clarity
    are necessary. See Ariad Pharms., Inc. v. Eli Lilly & Co.,
    
    598 F.3d 1336
     (Fed. Cir. 2010):
    [The claims’] principal function, therefore, is to pro-
    vide notice of the boundaries of the right to exclude
    and to define limits; it is not to describe the inven-
    tion, although their original language contributes
    to the description and in certain cases satisfies it.
    Claims define and circumscribe, the written de-
    scription discloses and teaches.
    
    Id. at 1347
    . See Nautilus, Inc. v. Biosig Instruments, Inc.,
    
    572 U.S. 898
    , 909 (2014) (“a patent must be precise enough
    to afford clear notice of what is claimed, thereby ‘ap-
    pris[ing] the public of what is still open to them.’” (quot-
    ing Markman, 
    517 U.S. at 373
    )).
    The claims are viewed and understood in the context of
    the specification and the prosecution history, as the Court
    summarized in Nautilus:
    Cognizant of the competing concerns, we read
    § 112, ¶ 2 to require that a patent’s claims, viewed
    in light of the specification and prosecution history,
    inform those skilled in the art about the scope of
    the invention with reasonable certainty. The defi-
    niteness requirement, so understood, mandates
    clarity, while recognizing that absolute precision is
    unattainable.
    572 U.S. at 910. When the meaning or scope of a patent
    claim is disputed by litigants, the judicial role is to construe
    the claim as a matter of law, on review of appropriate
    sources of relevant information. As summarized in Phillips
    v. AWH Corp., the court looks first to the intrinsic record of
    the patent document, including “the words of the claims
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    NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.               9
    themselves, the remainder of the specification, the prose-
    cution history, and extrinsic evidence concerning relevant
    scientific principles, the meaning of technical terms, and
    the state of the art.” 
    415 F.3d 1303
    , 1314 (Fed. Cir. 2005)
    (en banc) (quoting Innova/Pure Water, Inc. v. Safari Water
    Filtration Sys., Inc., 
    381 F.3d 1111
    , 1116 (Fed. Cir. 2004)).
    Here, however, the district court did not construe the
    claims, did not apply the protocols of intrinsic and extrinsic
    evidence, and did not resolve the meaning and scope of the
    challenged claims. The district court applied an incorrect
    standard of “unanswered questions” and a flawed analysis
    of validity.
    The district court’s standard of “unanswered
    questions”
    The district court held the claims indefinite based on
    the “unanswered questions” that were suggested by Auto-
    desk’s expert. For the term “searching neighboring trian-
    gles of the last triangle pair that holds the last intersection
    point,” the court recited three unanswered questions:
    Aliaga points to several unanswered questions
    about this language: (1) whether the phrase re-
    quires searching repeatedly or iteratively or merely
    once; (2) what the “last triangle pair” or “last inter-
    section point” is; (3) how can one “extend an inter-
    section line” when in some cases it is not possible,
    as Aliaga demonstrates.
    Dist. Ct. Op. at 17–18 (citing Aliaga Decl. ¶ 26).
    For the term “modified Watson method,” the district
    court recited four unanswered questions provided by Auto-
    desk’s expert:
    The claim language leaves unanswered the follow-
    ing questions: (1) What is a neighboring point of in-
    tersection (referred to as PET in the patents)?; (2)
    What is the meaning of an ‘identical’ point of
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    10         NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.
    intersection?; (3) What is the meaning of removing
    a point of intersection?; (4) From what is the point
    of intersection being removed? NSS does not re-
    spond to these specific questions, which highlight
    the ambiguity of the claim language.
    Dist. Ct. Op. at 9.
    In response to NSS’s argument that these questions
    are answered in the specification, the court held that defi-
    niteness requires that the questions are answered in “the
    claim language, standing alone,” as stated in the Aliaga
    Declaration:
    ¶ 27. [T]he claim language, standing alone,
    does not specify which of those neighboring, inter-
    secting triangles should be used to identify addi-
    tional intersection points. Nor does the claim
    specify (where there are multiple potential inter-
    section points for a given pair of neighboring trian-
    gles) which of the multiple potential intersection
    points should be used to extend the intersection
    line. Thus, the claim language is indefinite.
    Aliaga Decl. ¶ 27. “Claim language, standing alone” is not
    the correct standard of law, and is contrary to uniform
    precedent. Patent claims are viewed and understood in
    light of the specification, the prosecution history, and other
    relevant evidence, as “would have allowed a skilled artisan
    to know the scope of the claimed invention with reasonable
    certainty.” Sonix Tech., 844 F.3d at 1376.
    The district court did not apply this standard protocol
    for analyzing claim definiteness, and did not construe the
    claims. Instead, the court held that the questions raised
    by Autodesk must be answered, and that the answers must
    be in the claims. NSS states that on the correct claim con-
    struction, the claims are not indefinite.
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    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.               11
    The specification
    The specification describes the invention in text, draw-
    ings, and flowcharts. NSS states on this appeal that even
    if the theory of “unanswered questions” were accepted, any
    relevant questions are answered in the specification. For
    example, with respect to the intersection points that were
    a focus of the criticism recited by the district court, NSS
    cites the description in the specification captioned “The
    First Intersection Point” and “Extending an Intersection
    Line.” ’961 patent, col.5, l.41–col.6, l.24. NSS also points
    to the Figure 4 flowchart for building intersection lines, to
    Figures 6A and 6B for showing intersection points, and
    Figures 9A–9D for examples of intersection lines.
    The specification describes, and the claim recites, that
    the intersection line is built from the intersection points
    around the objects being compared, “searching neighboring
    triangles of the last triangle pair that holds the last inter-
    section point to extend the intersection line until the first
    intersection point is identical to the last intersection point
    of the intersection line ensuring that the last line gets
    closed or until all triangles are traversed.” ’961 patent,
    col.9, ll.23–33.
    Figure 13 is a flowchart of “Delaunay mesh modified
    Watson method that created the sequence” shown in Fig-
    ure 12. Figures 12A–12H show the decomposition of a
    square into triangles, the placement of intersection points
    within those triangles, and the use of triangles containing
    intersection points to build polygons from which new trian-
    gles are generated, along with comparisons with the prior
    art Watson method. Figure 13 shows that where any tri-
    angle contains a valid intersection point, the claimed
    method “moves the triangle to the deleted Triangle Set,
    uses deleted Triangle Set to build a polygon,” and “uses the
    polygon to generate triangles.”
    The specification describes the Watson and Delaunay
    prior art, in text and drawings to show how they are used
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    12         NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.
    and modified in the subject invention. Dr. Aliaga acknowl-
    edged this prior art in his expert declaration, stating: “To
    be clear, I am familiar with the Delaunay method, which is
    a known method of triangulation that is mentioned in the
    patents. . . . And I am also aware of the ‘Watson’ algorithm
    for computing a Delaunay triangulation that is described
    in a 1981 paper by D.F. Watson cited in the patents.” Ali-
    aga Decl. ¶ 15.
    The claims are properly viewed in light of this
    knowledge, for this prior art constitutes “extrinsic evidence
    concerning relevant scientific principles [and] the meaning
    of technical terms.” Phillips, 415 F.3d at 1313 (quoting In-
    nova/Pure Water, 
    381 F.3d at 1116
    ). The Court guided in
    Nautilus:
    One must bear in mind, moreover, that patents are
    “not addressed to lawyers, or even to the public
    generally,” but rather to those skilled in the rele-
    vant art. Carnegie Steel Co. v. Cambria Iron
    Co., 
    185 U.S. 403
    , 437 (1902) (also stating that
    “any description which is sufficient to apprise
    [steel manufacturers] in the language of the art of
    the definite feature of the invention, and to serve
    as a warning to others of what the patent claims as
    a monopoly, is sufficiently definite to sustain the
    patent”).
    572 U.S. at 909. The function of the claims is not to
    duplicate the specification.
    The district court declined to consider information in
    the specification that was not included in the claims. For
    example, in rejecting NSS’s argument that the modified
    Watson method is described in the specification, the dis-
    trict court stated:
    NSS points to column 7 of the specification and re-
    lies on step 5(a) of column 7 to show the modifica-
    tion of the Watson method. (’961 patent at 7:17–
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    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.              13
    23). This language adds an additional condition:
    “or last segment passes through the triangle.”
    Again, this language is not contained in the claim
    language and does not explain the challenged claim
    language.
    Dist. Ct. Op. at 10.
    The district court misperceived the function of patent
    claims; see In re Vamco Machine & Tool, Inc., 
    752 F.2d 1564
    (Fed. Cir. 1985):
    The function of claims is (a) to point out what the
    invention is in such a way as to distinguish it from
    what was previously known, i.e., from the prior art;
    and (b) to define the scope of protection afforded by
    the patent. In both of those aspects, claims are not
    technical descriptions of the disclosed inventions
    but are legal documents like the descriptions of
    lands by metes and bounds in a deed which define
    the area conveyed but do not describe the land.
    
    Id.
     at 1577 n.5 (emphases original). As noted in SRI Inter-
    national v. Matsushita Electric Corp. of Am., 
    775 F.2d 1107
    , 1121 n.14 (Fed. Cir. 1985): “Specifications teach.
    Claims claim.”
    The prosecution history
    The prosecution history here is significant, for the pa-
    tent examiner had initially rejected the claims on the
    ground of indefiniteness, and the examiner required addi-
    tional definition in the claim clauses here at issue. For ex-
    ample, the examiner had initially rejected the claims for
    indefiniteness of the clause “extending intersection lines
    until they get closed by searching neighboring triangles;”
    the examiner wrote: “What is causing the closure of the in-
    tersection lines? The nexus between ‘extending the inter-
    section lines’ and ‘searching neighboring triangle pairs’ is
    also not clearly set forth.” Appl. No. 15/840,052, Official
    Action (Non-Final Rejection) of Feb. 6, 2018, at 3. The
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    14         NATURE SIMULATION SYSTEMS INC.      v. AUTODESK, INC.
    applicant, in consultation with the examiner, amended this
    term in claim clause [2], as shown in the prosecution rec-
    ord:
    [2] building intersection lines starting with and
    ending with searching for the first pair of triangles
    that hold a start point of an intersection line by de-
    tecting whether two minimum bounding boxes
    overlap and performing edge-triangle intersection
    calculations for locating an intersection point, ex
    tending the intersection lines until they get closed
    by searching neighboring triangles or all triangles
    are traversed; then searching neighboring trian-
    gles of the last triangle pair that holds the last in-
    tersection point to extend the intersection line until
    the first intersection point is identical to the last
    intersection point of the intersection line ensuring
    that the intersection line gets closed or until all tri-
    angles are traversed;
    Appl. No. 15/840,052, Amend. of Apr. 4, 2018, at 9 (mark-
    ings in original). With this amendment the examiner with-
    drew the indefiniteness rejection relating to the
    intersection lines.
    The applicant and the examiner also interacted to
    amend the term “modified Watson method.” An Exam-
    iner’s Amendment of August 28, 2018 amended claim
    clause [3] as follows:
    [3] splitting each triangle through which an inter-
    section line passes using modified Watson method,
    wherein the modified Watson method includes re-
    moving duplicate intersection points, identifying
    positions of end intersection points, and splitting
    portion of each triangle including an upper portion,
    a lower portion, and a middle portion;
    Appl. No. 15/840,052, Examiner’s Amend. in Notice of Al-
    lowance, Sept. 18, 2018, at 4–5 (markings in original).
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    NATURE SIMULATION SYSTEMS INC.     v. AUTODESK, INC.             15
    With the agreed amendments, the examiner withdrew
    the rejections for indefiniteness and allowed the claims. 
    Id.
    However, the district court rejected the examiner’s con-
    clusion as to indefiniteness, the court reciting the initial
    rejection and the amendment, and stating that this action
    did not answer “the questions posed by Aliaga”:
    The prosecution history does not show how or why
    the amendment answered the unanswered ques-
    tions. The prosecution history does not provide a
    clear reason for the amendment that clarifies the
    underling ambiguity. The PTO initially rejected
    Claim 1 as indefinite: “The nexus between ‘extend-
    ing the intersection lines’ and ‘searching neighbor-
    ing triangles’ is also not clearly set forth. The
    examiner is not able to ascertain the scope of the
    claimed invention,” (Dkt. 37-1 (Ex. A at page 4).)
    In response, NSS added the following language:
    “building intersection lines starting with and end-
    ing with . . . calculations for locating an intersection
    point, then searching neighboring triangles of the
    last triangle pair that holds the last intersection
    point to extend the intersection line until the first
    intersection point is identical to the last intersec-
    tion point of the intersection line ensuring that the
    intersection line gets closed or until all triangles
    are traversed.” (Id.) This added language does not
    answer the questions posed by Aliaga.
    Dist. Ct. Op. at 19 (ellipses and parentheticals in original).
    The district court gave no weight to the prosecution
    history showing the resolution of indefiniteness by adding
    the designated technologic limitations to the claims. The
    court did not discuss the Examiner’s Amendment, and held
    that since Dr. Aliaga’s questions were not answered, the
    claims are invalid.
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    16         NATURE SIMULATION SYSTEMS INC.    v. AUTODESK, INC.
    Actions by PTO examiners are entitled to appropriate
    deference as official agency actions, for the examiners are
    deemed to be experienced in the relevant technology as
    well as the statutory requirements for patentability:
    We presume that an examiner would not introduce
    an indefinite term into a claim when he/she chooses
    to amend the claim for the very purpose of putting
    the application in a condition for allowance.
    Tinnus Enters., LLC v. Telebrands Corp., 733 F. App’x
    1011, 1020 (Fed. Cir. 2018). See also PowerOasis, Inc. v. T-
    Mobile USA, Inc., 
    522 F.3d 1299
    , 1304 (Fed. Cir. 2008)
    (stating that PTO examiners are “assumed to have some
    expertise in interpreting the references and to be familiar
    from their work with the level of skill in the art and whose
    duty it is to issue only valid patents.” (quoting Am. Hoist &
    Derrick Co. v. Sonra & Sons, Inc., 
    725 F.2d 1350
    , 1359
    (Fed. Cir. 1984) (overruled on other grounds))).
    The Court recognized, in discussing claim definiteness,
    that:
    The standard we adopt accords with opinions of
    this Court stating that “the certainty which the law
    requires in patents is not greater than is reasona-
    ble, having regard to their subject-matter.” Miner-
    als Separation, Ltd. v. Hyde, 
    242 U.S. 261
    , 270
    (1916).
    Nautilus, 572 U.S. at 910.
    The subject matter herein is an improvement on the
    known Watson and Delaunay methods, and partakes of
    known usages for established technologies. Precedent
    teaches that when “the general approach was sufficiently
    well established in the art and referenced in the patent”
    this “render[ed] the claims not indefinite.” Presidio Com-
    ponents, Inc. v. Am. Tech. Ceramics Corp., 
    875 F.3d 1369
    ,
    1377 (Fed. Cir. 2017). The situation here is analogous, for
    the 1981 Watson method and the Delaunay method were
    Case: 20-2257     Document: 31    Page: 17    Filed: 01/27/2022
    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.             17
    known in the art. It is not disputed that the specification
    describes and enables practice of the claimed method, in-
    cluding the best mode. The claims, as amended during
    prosecution, were held by the examiner to distinguish the
    claimed method from the prior art and to define the scope
    of the patented subject matter. The district court made no
    contrary findings. Indefiniteness under 
    35 U.S.C. § 112
    was not established as a matter of law.
    CONCLUSION
    The district court’s decision is reversed. We remand for
    further proceedings.
    REVERSED AND REMANDED
    Case: 20-2257    Document: 31      Page: 18   Filed: 01/27/2022
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    NATURE SIMULATION SYSTEMS INC.,
    Plaintiff-Appellant
    v.
    AUTODESK, INC.,
    Defendant-Appellee
    ______________________
    2020-2257
    ______________________
    Appeal from the United States District Court for the
    Northern District of California in No. 3:19-cv-03192-SK,
    Magistrate Judge Sallie Kim.
    ______________________
    DYK, Circuit Judge, dissenting.
    Contrary to the majority, I think that the asserted
    claims are invalid because they are indefinite. The fact
    that a patent examiner introduced the indefinite language
    does not absolve the claims from the requirements of 
    35 U.S.C. § 112
    . I respectfully dissent.
    The majority faults the district court for applying an
    incorrect “unanswered questions” standard, Maj. Op. 9, but
    this is not the district court’s decision. In a detailed and
    thorough analysis, the district court read the patent’s
    claims in light of the specification to determine if it would
    inform those skilled in the art about the scope of the inven-
    tion with reasonable certainty, which is exactly what is re-
    quired under Nautilus, Inc. v. Biosig Instruments, Inc., 572
    Case: 20-2257    Document: 31      Page: 19     Filed: 01/27/2022
    2         NATURE SIMULATION SYSTEMS INC.     v. AUTODESK, INC.
    U.S. 898, 910 (2014). Regardless, the question of definite-
    ness is a legal question which we review de novo, and the
    majority's legal conclusion is, in my view, manifestly incor-
    rect.
    The field of art here, computer-aided design, is unusu-
    ally complex, involving methods of using computer systems
    to build geometric objects. The patents purport to improve
    on two established methods of computer-aided design: con-
    structive solid geometry, which combines simple objects us-
    ing Boolean operations (e.g., intersection, combination,
    exclusion) to build complex objects, and boundary repre-
    sentation, which represents three-dimensional objects by
    defining their surfaces as meshes of two-dimensional ob-
    jects.
    Claim 1 of 
    U.S. Patent No. 10,120,961
     (“the ’961 pa-
    tent”) claims:
    1. A method that performs immediate Boolean op-
    erations using geometric facets of geometric objects
    implemented in a computer system and operating
    with a computer, the method comprising:
    mapping rendering facets to extended tri-
    angles that contain neighbors;
    building intersection lines starting with
    and ending with searching for the first pair
    of triangles that hold a start point of an in-
    tersection line by detecting whether two
    minimum bounding boxes overlap and per-
    forming edge-triangle intersection calcula-
    tions for locating an intersection point,
    then searching neighboring triangles of the
    last triangle pair that holds the last inter-
    section point to extend the intersection line
    until the first intersection point is identical
    to the last intersection point of the intersec-
    tion line ensuring that the intersection line
    Case: 20-2257    Document: 31      Page: 20    Filed: 01/27/2022
    NATURE SIMULATION SYSTEMS INC.   v. AUTODESK, INC.               3
    gets closed or until all triangles are trav-
    ersed;
    splitting each triangle through which an
    intersection line passes using modified
    Watson method, wherein the modified
    Watson method includes removing dupli-
    cate intersection points, identifying posi-
    tions of end intersection points, and
    splitting portion of each triangle including
    an upper portion, a lower portion, and a
    middle portion . . . .
    ’961 patent, col. 9, ll. 17–40; see also 
    U.S. Patent No. 10,109,105,
     col. 8, l. 47–col. 9, l. 3. (emphasis added). The
    indefiniteness issue concerns the underscored language.
    There is no dispute that the term “modified Watson
    method” does not have, and did not have at the time the
    patents were issued, an ordinary and customary meaning
    to a person of ordinary skill in the art. The majority finds
    that Figures 12 and 13 of each patent define the “modified
    Watson method.” Maj. Op. 11–12 (“The specification de-
    scribes the Watson and Delaunay prior art, in text and
    drawings to show how they are used and modified in the
    subject invention.”). Figures 12A through 12H of the pa-
    tents at issue “show a Delaunay mesh sequence in which
    each intersection point is inserted into the mesh step by
    step,” while Figure 13 “is the flowchart of Delaunay mesh
    modified Watson method that created the sequence of [Fig-
    ures] 12A through 12H.” ’961 patent, col. 3, ll. 36–41.
    The problem with the majority’s definition is that it ig-
    nores the claim language. As the district court found, J.A.
    9–10, and Nature concedes, Nature Reply Br. 6, claim 1
    adds limitations not found in Figures 12A–H or 13: “remov-
    ing duplicate intersection points, identifying positions of
    end intersection points, and splitting portion of each trian-
    gle including an upper portion, a lower portion, and a mid-
    dle portion.” Thus, the majority’s definition of “modified
    Case: 20-2257    Document: 31      Page: 21    Filed: 01/27/2022
    4         NATURE SIMULATION SYSTEMS INC.     v. AUTODESK, INC.
    Watson method” in claim 1 is inconsistent with the claim
    itself: the majority looks to figures 12 and 13 to find the
    “modified Watson method” but those figures do not include
    the additional limitations which are expressly required by
    the claim language. Even more significant, nothing in the
    patent specification defines what these additional limita-
    tions mean. The only expert evidence on these limitations
    in the record is by Autodesk’s expert, who testified without
    contradiction that these limitations are “not describe[d]” in
    the patent, “ambiguous” and “unclear,” and “inconsistent
    with” Figure 13 and the accompanying text. J.A. 54–56.
    The majority simply does not address this problem, in-
    stead relying on the fact that these limitations were sug-
    gested by the patent examiner. The majority holds that
    “[a]ctions by PTO examiners are entitled to appropriate
    deference” because examiners are “deemed to be experi-
    enced in the relevant technology as well as the statutory
    requirements for patentability.” Maj. Op. 16. But the test
    for definiteness is whether the claims “inform those skilled
    in the art about the scope of the invention with reasonable
    certainty,” Nautilus, 572 U.S. at 910, not whether the claim
    language was added by a patent examiner or was not in-
    definite to the examiner. There is no reasonable basis in
    the claims or specification for the majority’s decision. I re-
    spectfully dissent.