Case: 19-1557   Document: 88     Page: 1   Filed: 05/20/2020




   United States Court of Appeals
       for the Federal Circuit
                 ______________________

          MCRO, INC., DBA PLANET BLUE,
                 Plaintiff-Appellant

                            v.

      BANDAI NAMCO GAMES AMERICA INC.,
          TREYARCH CORPORATION,
                 Defendants

  SONY COMPUTER ENTERTAINMENT AMERICA
    LLC, SUCKER PUNCH PRODUCTIONS, LLC,
  INFINITY WARD, INC., LUCASARTS, A DIVISION
   OF LUCASFILM ENTERTAINMENT COMPANY
    LTD. LLC, ACTIVISION PUBLISHING, INC.,
   BLIZZARD ENTERTAINMENT, INC., NAUGHTY
   DOG, INC., ELECTRONIC ARTS, INC., DISNEY
   INTERACTIVE STUDIOS, INC., SQUARE ENIX,
                       INC.,
                Defendants-Appellees
               ______________________

                       2019-1557
                 ______________________

     Appeal from the United States District Court for the
 Central District of California in Nos. 2:12-cv-10322-GW-
 FFM, 2:12-cv-10329-GW-FFM, 2:12-cv-10333-GW-FFM,
 2:12-cv-10335-GW-FFM, 2:12-cv-10338-GW-FFM, 2:14-cv-
 00332-GW-FFM, 2:14-cv-00336-GW-FFM, 2:14-cv-00352-
 GW-FFM, 2:14-cv-00358-GW-FFM, 2:14-cv-00383-GW-
 FFM, Judge George H. Wu.
Case: 19-1557    Document: 88      Page: 2   Filed: 05/20/2020




 2                MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



                  ______________________

                  Decided: May 20, 2020
                  ______________________

    MARK STEWART RASKIN, King & Wood Mallesons LLP,
 New York, NY, for plaintiff-appellant. Also represented by
 MICHAEL DEVINCENZO, JOHN FRANCIS PETRSORIC, ROBERT
 WHITMAN; MARC AARON FENSTER, PAUL ANTHONY
 KROEGER, Russ August & Kabat, Los Angeles, CA.

    JOHN D. GARRETSON, Shook, Hardy & Bacon, LLP,
 Kansas City, MO, for defendants-appellees Sony Computer
 Entertainment America LLC, Sucker Punch Productions,
 LLC, Naughty Dog, Inc. Also represented by BETH A.
 LARIGAN.

     SONAL NARESH MEHTA, Wilmer Cutler Pickering Hale
 and Dorr LLP, Palo Alto, CA, for defendants-appellees In-
 finity Ward, Inc., Activision Publishing, Inc., Blizzard En-
 tertainment, Inc., Electronic Arts, Inc.

    EVAN FINKEL, Pillsbury Winthrop Shaw Pittman LLP,
 Los Angeles, CA, for defendants-appellees LucasArts, Dis-
 ney Interactive Studios, Inc. Also represented by JAMES
 CHANG.

      BENJAMIN J. FOX, Morrison & Foerster LLP, Los Ange-
 les, CA, for defendant-appellee Square Enix, Inc. Also rep-
 resented by WENDY J. RAY.
                   ______________________

     Before REYNA, MAYER, and TARANTO, Circuit Judges.
 TARANTO, Circuit Judge.
     McRO, Inc., d/b/a Planet Blue (McRO) brought this
 case against more than a dozen video game developers (the
 Developers), alleging that the Developers infringed three
Case: 19-1557      Document: 88    Page: 3    Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                 3



 method claims of U.S. Patent No. 6,611,278, owned by
 McRO. The district court held the claims invalid for ineli-
 gibility under 35 U.S.C. § 101, but we reversed that holding
 in McRO, Inc. v. Bandai Namco Games America Inc., 837
 F.3d 1299 (Fed. Cir. 2016) (McRO I). On remand, the dis-
 trict court ultimately held that the Developers were enti-
 tled to summary judgment of noninfringement because the
 accused products do not practice the claimed methods and
 to summary judgment of invalidity because the specifica-
 tion fails to enable the full scope of the claims.
     McRO appeals. We affirm the judgment of noninfringe-
 ment. We vacate the judgment of invalidity and remand
 for the district court to consider any appropriate further
 proceedings in light of, among other things, the Developers’
 offer to withdraw their counterclaims without prejudice.
 See ECF No. 86.
                               I
                              A
      McRO owns U.S. Patent No. 6,611,278, which describes
 and claims a method for automatically generating anima-
 tions, with a three-dimensional appearance, depicting lip
 movements and facial expressions. The method uses two
 basic building blocks: “phonemes” and “morph targets.” A
 “phoneme,” the patent explains, is “the smallest unit of
 speech, and corresponds to a single sound.” ’278 patent,
 col. 1, lines 38–40. A “morph target” is a model of a mouth
 position—one “reference model” displays a “neutral mouth
 position,” while other models display “other mouth posi-
 tions, each corresponding to a different phoneme or set of
 phonemes.” Id., col. 1, lines 48–53.
     The patent describes specifying a model by identifying
 groups of vertices placed in particular positions. In a “typ-
 ical case,” “[e]ach morph target has the same topology as
 the neutral model, the same number of vertices, and each
 vertex on each model logically corresponds to a vertex on
Case: 19-1557      Document: 88      Page: 4    Filed: 05/20/2020




 4                 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 each other model.” Id., col. 1, lines 54–59. Because of that
 precise correspondence, each morph target can be defined
 as a set of “deltas,” each delta a vertex-specific vector: there
 is a “vector from each vertex n on the reference to each ver-
 tex n on each morph target,” and that vector is the “delta”
 for that vertex. Id., col. 1, lines 60–63.
     To animate a particular facial expression, an artist de-
 fines a plurality of morph targets (with corresponding delta
 sets) and assigns a scalar “morph weight”—“a value usu-
 ally from 0 to 1”—to each target. Id., col. 1, lines 65–67.
 Next, the artist chooses a vertex on the reference model
 and adds the “corresponding delta set’s vertex multiplied
 by the scalar morph weight.” Id., col. 2, lines 1–3. Repeat-
 ing this vertex-specific process for each morph target being
 used to create the desired animation, the artist sums the
 resulting vectors and proceeds to the next reference-model
 vertex. See id., col. 2, lines 4–5. The specification summa-
 rizes this process with a formula, stating that for “each ver-
 tex v in the neutral model”:




 J.A. 15 (cleaning up ’278 patent, col. 2, line 6). 1



     1    In the sigma (summation) term of the formula,
 there are n morph targets (x = 1 through n) that contribute
 to the ultimate result. For each morph target x, its delta (a
 vector) for the chosen vertex—i.e., the particular vertex’s
 vector within |delta setx|—is multiplied by the scalar
 morph weight for that morph target. The n resulting vec-
 tors (for x = 1 through n) are added in the ordinary way for
 vectors, i.e., term by term in the ordered-sequence repre-
 sentation. Then the sum, in its ordered-sequence represen-
 tation, is added to the ordered-sequence representation of
 the corresponding vertex of the neutral model.
Case: 19-1557      Document: 88     Page: 5     Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                    5



      Although prior-art methods used morph weight sets,
 the patent asserts, artists using those methods had to “set
 all of these weights at each frame to an appropriate value.”
 ’278 patent, col. 2, lines 26–27. Accordingly, those methods
 were time-consuming and laborious, and artists therefore
 sought to reduce the required work with a “‘keyframe’ ap-
 proach, where the artist [would] set[] the appropriate
 weights at certain important times (‘keyframes’) and a pro-
 gram [would] interpolate[] each of the channels at each
 frame.” Id., col. 2, lines 28–31. But the keyframe approach
 itself was “very tedious and time consuming, as well as in-
 accurate.” Id., col. 2, lines 31–34.
      By contrast, the ’278 patent teaches a method of “auto-
 matically” generating animations using morph weight sets.
 In particular, it describes a method in which a time-
 marked transcript of recorded text denoting each pho-
 neme—a “time aligned phonetic transcription” (TAPT)—is
 received by a computer system. Id., col. 2, line 64, through
 col. 3, line 5. The system takes this input and applies “a
 set of rules that determine the system[’]s output compris-
 ing a stream or streams of morph weight sets.” Id., col. 3,
 lines 2–5. The specification describes an exemplary set of
 rules, with six distinct morph targets, for animating the
 word “hello.” See id., col. 7, line 33, through col. 8, line 55.
 It further provides several “illustrative examples of other
 rules which may be used.” See id., col. 9, line 32, through
 col. 11, line 11.
      McRO asserts claims 1, 4, and 13 of its patent. Claim
 1 is representative for purposes of the issues on appeal:
     1. A method for automatically animating lip syn-
     chronization and facial expression of three-dimen-
     sional characters comprising:
     obtaining a first set of rules that defines a morph
           weight set stream as a function of phoneme
           sequence and times associated with said
           phoneme sequence;
Case: 19-1557     Document: 88      Page: 6   Filed: 05/20/2020




 6                 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



     obtaining a plurality of sub-sequences of timed
           phonemes corresponding to a desired audio
           sequence for said three-dimensional charac-
           ters;
     generating an output morph weight set stream by
           applying said first set of rules to each sub-
           sequence of said plurality of sub-sequences
           of timed phonemes; and
     applying said output morph weight set stream to
           an input sequence of animated characters to
           generate an output sequence of animated
           characters with lip and facial expression
           synchronized to said audio sequence.
 Id., col. 11, lines 44–59.
                                B
      In 2012, McRO sued the Developers for patent infringe-
 ment based on the Developers’ production and sale of video
 games that used one of two third-party software applica-
 tions—FaceFX or Annosoft—to model facial animations.
 Both FaceFX and Annosoft use a technique called “bones
 animation,” which attaches “special control objects (called
 ‘bones’)” to multiple vertices on a three-dimensional image
 (i.e., an image that looks three-dimensional). J.A. 4649.
 Each bone stores information, whether as a 4x4 matrix or
 as an equivalent 16-term vector, that acts as a “transform”
 to direct the attached vertices to move to certain positions.
 J.A. 4650. This movement, which can be complex, gener-
 ally combines “simpler linear transformations such as ro-
 tations, translations, [or] scales.” Id. Because a vertex can
 attach to multiple bones, each bone is assigned a weight
 and the “resulting position of a vertex is determined by
 blending the transforms that it is attached to according to
 the weights.” J.A. 4649.
      After claim construction, the Developers filed a motion
 for judgment on the pleadings, arguing that each asserted
Case: 19-1557      Document: 88    Page: 7    Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                  7



 claim is invalid under 35 U.S.C. § 101. In 2014, the district
 court granted the Developers judgment on the pleadings
 and terminated the case. McRO, Inc. v. Sony Computer
 Entertainment America, LLC, 55 F. Supp. 3d 1214 (C.D.
 Cal. 2014). Although the claims “are tangible, each cover-
 ing an approach to automated three-dimensional computer
 animation,” the court noted, the claims “preempt the field
 of lip synchronization using a rules-based morph target ap-
 proach.” Id. at 1224, 1227.
     We reversed the district court’s determination. McRO
 I, 837 F.3d at 1302–03. Holding that the patent does not
 preempt the field of rules-based animation, we stated that
 the claims “are limited to rules with certain common char-
 acteristics, i.e., a genus.” Id. at 1313. Specifically, the
 “rules are limiting in that they define morph weight sets as
 a function of the timing of phoneme sub-sequences.” Id.
 Although “[p]atent law has evolved to place additional re-
 quirements on patentees seeking to claim a genus,” we ex-
 plained, “these limits have . . . principally been in terms of
 whether the patentee has satisfied the tradeoff of broad
 disclosure for broad claim scope implicit in 35 U.S.C.
 § 112.” Id. at 1313–14.
       The case returned to the district court, and in July
 2018, the court tentatively granted the Developers’ motion
 for summary judgment of noninfringement. The court con-
 cluded that the bones animation technique, because it does
 not use three-dimensional vectors for its movement of ver-
 tices, does not practice the “morph weight set” limitation.
 But, the court stated, it would “not issue a final ruling” un-
 til it determined whether the asserted claims of the ’278
 patent are enabled, as required by 35 U.S.C. § 112.
     In November 2018, the district court granted the De-
 velopers’ motion for summary judgment of invalidity (as-
 serted by most of the Developers through counterclaims).
 The district court noted that the Developers had identified
 two animation techniques—bones animation and the
Case: 19-1557     Document: 88       Page: 8   Filed: 05/20/2020




 8                 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 “BALDI system”—that are not enabled by the specification.
 McRO, Inc. v. Namco Bandai Games America, Inc., No. CV
 12-10322-GW(FFMx), 2018 WL 9410401, at *12 (C.D. Cal.
 Nov. 13, 2018) (Enablement Opinion). The court concluded
 that the Developers had provided clear and convincing ev-
 idence that “at the time of the invention, a person of skill
 in the art would not have the tools to practice the full scope
 of the ‘first set of rules’ limitation.” Id.
     The district court entered a final judgment of nonin-
 fringement and invalidity on January 9, 2019. McRO
 timely appealed to this court. We have jurisdiction pursu-
 ant to 28 U.S.C. § 1295(a)(1).
                                II
     We review the grant of summary judgment de novo and
 ask whether there is a “genuine dispute of material fact,
 after viewing the evidence in the light most favorable to the
 nonmoving party.” Weber v. Allergan, Inc., 940 F.3d 1106,
 1110 (9th Cir. 2019); Eli Lilly & Co. v. Hospira, Inc., 933
 F.3d 1320, 1327 (Fed. Cir. 2019) (applying regional circuit
 law). Claim construction is a legal question that may in-
 volve underlying factual findings. Teva Pharms. USA, Inc.
 v. Sandoz, Inc., 574 U.S. 318, 331–32 (2015). Similarly,
 whether a patent satisfies the enablement requirement is
 a question of law based on underlying factual findings. Wy-
 eth & Cordis Corp. v. Abbott Labs., 720 F.3d 1380, 1384
 (Fed. Cir. 2013). The party challenging the validity of the
 patent must provide clear and convincing evidence to sup-
 port such factual findings. Cephalon, Inc. v. Watson
 Pharms., Inc., 707 F.3d 1330, 1336 (Fed. Cir. 2013).
                                A
     We begin with McRO’s appeal of the judgment of non-
 infringement. We agree with the Developers that the claim
 term “morph weight set” requires three-dimensional vec-
 tors. That is, we conclude that the district court was cor-
 rect as a matter of law in ruling that a “vector,” in the
Case: 19-1557      Document: 88    Page: 9    Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                  9



 context of the ’278 patent, must have “3-D magnitude and
 direction computed by pure subtraction/addition between
 the neutral and target models, with one vector correspond-
 ing to each set of two vertices.” J.A. 16–17. Because the
 parties agree that there is no infringement under this con-
 struction, we affirm the district court’s grant to the Devel-
 opers of summary judgment of noninfringement.
      The district court construed the term “morph weight
 set” as “[a] set of values, one for each delta set, that, when
 applied, transform the neutral model to some desired state,
 wherein each delta set is the set of vectors from each vertex
 on the neutral (reference) model to each vertex on a model
 of another mouth position.” J.A. 902. This construction
 combines two express definitions from the specification—
 “morph weight set” is defined in terms of a “delta set,”
 which, in turn, is defined in terms of “vectors.” ’278 patent,
 col. 4, lines 35–37; id., col. 1, lines 60–62. The parties do
 not dispute this construction of “morph weight set.”
      The parties do dispute the meaning of “vector” within
 that construction. The district court construed “vector” as
 “a vector with direction and magnitude in three-dimen-
 sional space.” J.A. 21. This construction accords with the
 Developers’ argument that “the vectors constituting the
 ‘delta set’ must be vectors in three-dimensional space.”
 J.A. 7302. The construction rejects McRO’s proposal that
 the term should be construed as, simply, “an ordered set of
 numbers.” J.A. 6138. The court noted that it had already
 “rejected [McRO’s] request to construe ‘delta set’ in the con-
 text of ‘morph weight set’ as ‘wherein each delta set is the
 mathematical representation of the difference between the
 neutral model and another model,’” and the court con-
 cluded that McRO was “effectively urging the same imper-
 missibly broad meaning.” J.A. 17.
     The difference matters for assessing the accused bones
 system for infringement. The bones system, in its relevant
 aspect, uses vectors as that term is used in one general
Case: 19-1557     Document: 88       Page: 10     Filed: 05/20/2020




 10                 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 mathematical sense, i.e., any ordered collection of individ-
 ual terms such as (a1, a2, a3, . . ., an). But there is no dispute
 that the relevant aspect of the bones system does not come
 within the meaning of “vector” if that word is limited, in
 the ’278 patent, to the ordinary three-dimensional geomet-
 ric vector, which can be represented by a three-term se-
 quence (ax, ay, az), each term for one of the three spatial
 dimensions. The district court adopted the latter construc-
 tion, rejecting infringement on that basis.
      We agree with the district court. The proper claim con-
 struction is based “not only in the context of the particular
 claim in which the disputed term appears, but in the con-
 text of the entire patent, including the specification.” Phil-
 lips v. AWH Corp., 415 F.3d 1303, 1313–16 (Fed. Cir. 2005);
 see Ruckus Wireless, Inc. v. Innovative Wireless Solutions,
 LLC, 824 F.3d 999, 1003 (Fed. Cir. 2018) (“Ultimately,
 ‘[t]he only meaning that matters in claim construction is
 the meaning in the context of the patent.’” (quoting Trus-
 tees of Columbia Univ. v. Symantec Corp., 811 F.3d 1359,
 1365 (Fed. Cir. 2016))). Here, the specification compels the
 three-dimensional geometric construction of “vector”
 adopted by the district court.
     Vertices in the neutral model (points on a face) are lo-
 cations in three-dimensional space, and the specification’s
 express definition of “delta set” requires a one-to-one corre-
 spondence between the vertices of the neutral model and
 the vertices of each morph target, with a “vector” connect-
 ing these corresponding vertices in three-dimensional
 space. According to the specification, a “delta” is “com-
 puted as a vector from each vertex n on the reference to each
 vertex n on each morph target.” ’278 patent, col. 1, lines
 60–62 (emphasis added). The term “vertex” naturally car-
 ries a spatial meaning, as do the words “from” and “to,” and
 they imply that a delta is a direct path from the vertex (a
 spatial point) on the reference to the vertex (a spatial point)
 on the morph target, i.e., a three-dimensional vector. The
 conclusion is reinforced by the specification’s statement, in
Case: 19-1557     Document: 88     Page: 11     Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                  11



 the paragraph preceding the definitional sentence, that
 “[e]ach morph target has the same topology as the neutral
 model . . . .” Id., col. 1, lines 53–56 (emphasis added). All
 these terms strongly favor the narrow geometric meaning
 of “vector”—especially in the spatial context of the inven-
 tion, reflected in claim 1’s stated object of creating visually
 recognizable “three-dimensional characters.” Id., col. 11,
 line 44.
     The equation in the specification confirms the require-
 ment of three-dimensional vectors that can be added and
 subtracted. Each delta set (a set of vectors) is assigned a
 “scalar” morph weight, “usually from 0 to 1,” and each vec-
 tor is multiplied by that scalar value. See id., col. 1, line
 65, through col. 2, line 3. Then, the corresponding scalar-
 multiplied vectors from each set are added together—these
 summations are, finally, added to the corresponding neu-
 tral vertices. Id., col. 2, lines 5–9. The specification pro-
 vides an equation that summarizes this process:




 J.A. 15 (cleaning up ’278 patent, col. 2, line 6).
      The specification’s surrounding discussion confirms
 that this equation is naturally understood as referring to
 three-dimensional vectors. The “symbol |xxx| is used to
 indicate the corresponding vector in each referenced set,”
 the specification explains, and, specifically, |neutral| rep-
 resents “vertex v in the neutral model.” See ’278 patent,
 col. 2, lines 5–13. The vertex in the neutral model (a point
 on a face) is a location in three-dimensional space, which is
 represented by a three-dimensional vector from the Carte-
 sian origin. Accordingly, to add |neutral| to the result of
 the summation, the result of the summation must be a
 three-dimensional vector.         And to get that result,
 |delta setx| must also be a three-dimensional vector.
 Thus, the equation strongly supports the district court’s
Case: 19-1557    Document: 88      Page: 12   Filed: 05/20/2020




 12               MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 construction: a “vector” must have “3-D magnitude and di-
 rection computed by pure subtraction/addition between the
 neutral and target models, with one vector corresponding
 to each set of two vertices.” J.A. 16–17.
      McRO offers two arguments that this specification evi-
 dence should be interpreted differently. The first argu-
 ment, which relies on the key definitional sentence,
 misreads our precedent and ignores most of the language
 in that sentence. According to McRO, the phrase “a vector
 from each vertex n on the reference” implies that each ver-
 tex on the reference can have multiple corresponding vec-
 tors because “it is a well settled rule that the article ‘a’
 means one or more and not ‘a single.’” Brief for Appellant
 at 24 (citing KCJ Corp. v. Kinetic Concepts, Inc., 223 F.3d
 1351, 1356 (Fed. Cir. 2000)). The patent would have used
 the phrase “a single vector,” McRO argues, if it had meant
 to require one-to-one correspondence. Id. But McRO mis-
 reads KCJ Corp., which explains that “an indefinite article
 ‘a’ or ‘an’ in patent parlance carries the meaning of ‘one or
 more’ in open-ended claims containing the transitional
 phrase ‘comprising.’” 223 F.3d at 1356 (emphasis added).
 This specific canon of claim construction has no bearing
 here. And as discussed, the word “a” is hardly the only rel-
 evant textual evidence of meaning.
      McRO’s second argument, which relies on the para-
 graph in the specification that precedes the key definitional
 sentence, gives too much weight to an ambiguous phrase
 that does not clearly refer to the relevant term. After dis-
 cussing the topological correspondence between the neu-
 tral model and each morph target, the passage states that
 “such rigid correspondence may not be necessary.” Id., col.
 1, lines 58–59. This language, McRO contends, overrides
 the natural understanding of all the specification evidence
 we have discussed and renders the specification’s guidance
 optional. But the statement that “such rigid correspond-
 ence may not be necessary” is too equivocal and uncertain
 to alter the clear teaching of the specification. Indeed, it
Case: 19-1557     Document: 88     Page: 13     Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                  13



 does not even refer specifically to the claim term, “morph
 weight set”; it might be referring to some notion independ-
 ent of that claim limitation, which, by the specification, is
 defined to include the “vector” requirement. Nothing in the
 specification shows a use of “vector,” or representation of
 “delta sets” (sets of vectors), other than the ordinary, geo-
 metric, three-dimensional one.
      What remains is McRO’s brief argument, relying on ex-
 trinsic evidence, that one ordinary meaning of “vector” is
 broader than the district court’s construction. Citing a
 computer graphics textbook called “Real Time Rendering,”
 Dr. Gleicher (McRO’s expert) stated that “[t]he term ‘vec-
 tor’ in mathematics, computer science and computer
 graphics is a general concept that roughly means an or-
 dered list of numbers.” J.A. 2289 (citing J.A. 2068–69). It
 is, in fact, not disputed that one broad meaning of “vector”
 in mathematics and other fields is an “ordered list of num-
 bers.” But the existence of one broader meaning in the field
 is not controlling. What matters is the meaning most ap-
 propriate in the context of the particular patent. Here, it
 is clear, based on the intrinsic evidence, that the term “vec-
 tor” has the narrower geometric meaning in this patent.
 That construction, as is undisputed, compels the judgment
 of noninfringement, which we therefore affirm.
                               B
      We now address McRO’s appeal of the judgment of in-
 validity based on the specification’s failure to enable the
 full scope of claim 1’s required “first set of rules.” We agree
 with McRO that the Developers failed to identify with par-
 ticularity any method of animation that falls within the
 scope of claim 1 and is not enabled. Without any specific
 examples, the district court’s reasoning is too abstract, too
 conclusory, to support summary judgment. We do not go
 so far as to hold that there is a triable issue of fact on ena-
 blement—instead, we vacate the judgment and remand for
 the district court to consider how to proceed.
Case: 19-1557    Document: 88        Page: 14   Filed: 05/20/2020




 14                MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



                                 1
     The requirement of enablement, stated in 35 U.S.C.
 § 112, enforces the essential “quid pro quo of the patent
 bargain” by requiring a patentee to teach the public how
 “to practice the full scope of the claimed invention.” AK
 Steel Corp. v. Sollac, 344 F.3d 1234, 1244 (Fed. Cir. 2003).
 “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 . . .
 to make and use the same . . . .” 35 U.S.C. § 112 ¶ 1 (2006)
 (now § 112(a)). Although a patent’s specification need not
 “describe how to make and use every possible variant of the
 claimed invention,” “when a range is claimed, there must
 be reasonable enablement of the scope of the range.” AK
 Steel, 344 F.3d at 1244. To qualify as “reasonable,” “the
 specification . . . must teach those skilled in the art how to
 make and use the full scope of the claimed invention with-
 out ‘undue experimentation.’” ALZA Corp. v. Andrx
 Pharm., LLC, 603 F.3d 935, 940 (Fed. Cir. 2010) (citing
 Genentech Inc. v. Novo Nordisk A/S, 108 F.3d 1361, 1365
 (Fed. Cir. 1997)).
     This statutory requirement is limited to what is
 claimed. Section 112 requires enablement of “only the
 claimed invention,” not matter outside the claims. Union
 Carbide Chemicals & Plastics Tech. Corp. v. Shell Oil Co.,
 308 F.3d 1167, 1186 (Fed. Cir. 2002) (citing Durel Corp. v.
 Osram Sylvania Inc., 256 F.3d 1298, 1306–07 (Fed. Cir.
 2001)); Liquid Dynamics Corp. v. Vaughan Co., 449 F.3d
 1209, 1224 & n.2 (Fed. Cir. 2006); In re Vaeck, 947 F.2d
 488, 495 (Fed. Cir. 1991) (all that must be enabled is “the
 claimed invention”). For that reason, the “enablement in-
 quiry necessarily depends on an interpretation of the
 claims.” Liquid Dynamics, 449 F.3d at 1224 & n.2.
     Once the precise scope of the claimed invention is de-
 fined, the question is whether undue experimentation is
Case: 19-1557     Document: 88    Page: 15    Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                15



 required to make and use the full scope of embodiments of
 the invention claimed. See Union Carbide, 308 F.3d at
 1186 n.9 (“Evidence of unsuccessful experimentation with-
 out any link to the claims at issue is not evidence of a lack
 of enablement.”). Whether undue experimentation is re-
 quired “is not a single, simple factual determination, but
 rather is a conclusion reached by weighing many factual
 considerations.” ALZA, 603 F.3d at 940 (citing In re
 Wands, 858 F.2d 731, 737 (Fed. Cir. 1988)). Conducting
 the Wands analysis has routinely involved concrete identi-
 fication of at least some embodiment or embodiments as-
 serted not to be enabled—including what particular
 products or processes are or may be within the claim, so
 that breadth is shown concretely and not just as an ab-
 stract possibility, and how much experimentation a skilled
 artisan would have to undertake to make and use those
 products or processes. See, e.g., id. at 939–43 (conducting
 Wands analysis in terms of the specifically identified claim
 embodiments—tablets and capsules for oral medication
 dosages). 2




     2    In cases involving claims that state certain struc-
 tural requirements and also require performance of some
 function (e.g., efficacy for a certain purpose), we have ex-
 plained that undue experimentation can include undue ex-
 perimentation in identifying, from among the many
 concretely identified compounds that meet the structural
 requirements, the compounds that satisfy the functional
 requirement. See, e.g., Idenix Pharms. LLC v. Gilead Scis.
 Inc., 941 F.3d 1149, 1155–56 (Fed. Cir. 2019); Enzo Life
 Scis., Inc. v. Roche Molecular Systems, Inc., 928 F.3d 1340,
 1346–47, 1349 (Fed. Cir. 2019); Wyeth & Cordis Corp. v.
 Abbott Labs., 720 F.3d 1380, 1384, 1387 (Fed. Cir. 2013);
 Enzo Biochem, Inc. v. Calgene, Inc., 188 F.3d 1362, 1372
 (Fed. Cir. 1999); ALZA, 603 F.3d at 939.
Case: 19-1557    Document: 88      Page: 16   Filed: 05/20/2020




 16               MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



      All the enablement cases on which the district court re-
 lied, and on which the Developers rely in this court, in-
 volved specific identification of products or processes that
 were or may be within the scope of the claims and were
 allegedly not enabled. In Automotive Technologies Interna-
 tional, Inc. v. BMW of North America, for example, we con-
 sidered whether a claimed “side impact crash sensor for a
 vehicle having front and rear wheels” was enabled. 501
 F.3d 1274, 1277 (Fed. Cir. 2007). We observed that, under
 the governing claim construction (not disputed by the par-
 ties), the claim term embraced “electronic side impact sen-
 sors.” Id. at 1282. The enablement question, then, was a
 concrete one: whether the “specification did not enable the
 full scope of the invention because it did not enable elec-
 tronic side impact sensors.” Id.
     In Genentech, Inc. v. Novo Nordisk, A/S, 108 F.3d
 1361, 1367–68 (Fed. Cir. 1997), a case involving a func-
 tional cleaving property, the court noted the wide range of
 enzyme-protein combinations that were not enabled; in-
 deed, it concluded that the specification omitted crucial de-
 tails (e.g., starting materials, process conditions) for
 teaching even a single way of producing the claimed result
 for the identified matter. In MagSil Corp. v. Hitachi
 Global Storage Technologies, Inc., 687 F.3d 1377, 1381–83
 (Fed. Cir. 2012), the claim covered all changes in resistance
 of 10% or more (e.g., 100% or 1000%) in a particular pro-
 cess, and it was the lack of any teaching of how to achieve
 the resistance change even a little bit above 10% that was
 not enabled (and was concededly unknown at the time). In
 Sitrick v. Dreamworks, LLC, 516 F.3d 993, 999–1001 (Fed.
 Cir. 2008), the claim covered both video games and movies,
 and it was movies that the court held to be not enabled. In
 In re Vaeck, 947 F.2d at 495, the claims covered use of any
 of the many known species of cyanobacteria, but there was
 no enabling of the required gene expression in any but a
 small subset (and such expression in cyanobacteria was un-
 predictable). In Trustees of Boston University v. Everlight
Case: 19-1557     Document: 88      Page: 17     Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                    17



 Electronics Co. Ltd., 896 F.3d 1357, 1360, 1362 (Fed. Cir.
 2018), the parties agreed that the claim covered six permu-
 tations for the relationship between a growth layer and a
 buffer layer, and it was one of those permutations that the
 court concluded was not enabled. 3
     In short, none of the cases invoked by the district court
 and by the Developers have involved an abstract assertion
 of breadth, without concrete identification of matter that is
 not enabled but is or may be within the claim scope. As
 next explained, this case, in its current posture, involves
 such an abstract assertion of breadth. Under our claim
 construction, the bones and BALDI techniques are nonin-
 fringing and so cannot support a nonenablement determi-
 nation. And no other concretely identified animation
 techniques have been advanced to support the district
 court’s and Developers’ enablement analyses.
                                2
      The district court in this case determined that the spec-
 ification of the ’278 patent fails to enable claim 1’s “first set
 of rules” limitation. Enablement Opinion at *10. Specifi-
 cally, claim 1 requires “obtaining a first set of rules that
 defines a morph weight set stream as a function of pho-
 neme sequence and times associated with said phoneme



     3    See also Idenix, 941 F.3d at 1157 (vast number of
 substituents at positions on ring other than 2′-up); Enzo
 Life Scis., 928 F.3d at 1346–67, 1349 (all phosphate-labeled
 polynucleotides that are hybridizable and detectable, in-
 cluding any type of labels and linkages and any location of
 labels); Wyeth, 720 F.3d at 1384, 1387 (large number of
 compounds varying substituent groups outside a sirolimus
 ring and of potential rapamycin compounds); ALZA, 603
 F.3d at 939 (non-osmotic oral dosage forms—tablets and
 capsules); Enzo Biochem, 188 F.3d at 1372 (all eukaryotic
 and prokaryotic cell types).
Case: 19-1557    Document: 88       Page: 18   Filed: 05/20/2020




 18                MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 sequence.” ’278 patent, col. 11, lines 43–48. This claim, the
 specification reveals, requires at least two operations.
      First, the specification makes clear that obtaining the
 set of rules presupposes identifying which mouth shapes
 (morph targets) should be used for representing a particu-
 lar phoneme (or phoneme sequence) appearing on the “time
 aligned phonetic transcription” that is being synched to an
 animation. See id., col. 4, lines 31–45 (“The method prefer-
 ably comprises a set of rules that determine what the out-
 put morph weight set stream will be when any sequence
 o[f] phonemes and their associated times is encountered.”);
 id., col. 1, lines 49–53 (“morph targets” are models of mouth
 positions—one “reference model” corresponds to a “neutral
 mouth position,” while other models display “other mouth
 positions, each corresponding to a different phoneme or set
 of phonemes”). For example, the specification explains, an
 artist would have to know that “the ‘l’ in ‘hello’” requires a
 wider mouth shape than the “‘l’ in ‘burly.’” ’278 patent, col.
 10, lines 22–25.
     But on the record before us, this aspect of the claimed
 rules need not have been taught in the specification, and
 the district court did not rule otherwise. An “artisan’s
 knowledge of the prior art and routine experimentation can
 often fill gaps, interpolate between embodiments, and per-
 haps even extrapolate beyond the disclosed embodiments,
 depending upon the predictability of the art,” AK Steel, 344
 F.3d at 1244, and a “patent need not teach, and preferably
 omits, what is well known in the art,” Spectra-Physics, Inc.
 v. Coherent, Inc., 827 F.2d 1524, 1534 (Fed. Cir. 1987).
 Here, the district court explained that “both experts appar-
 ently agree that the state of computer animation overall
 and the development of rules for animation was well-devel-
 oped in other contexts.” Enablement Opinion at *17; see
 J.A. 4945 (McRO’s expert); J.A. 5772 (the Developers’ ex-
 pert). The specification itself indicates that animators
 knew how to match mouth positions to phonemes—doing
 so just took a significant amount of time because the
Case: 19-1557     Document: 88     Page: 19    Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                 19



 process was manual. See ’278 patent, col. 2, lines 26–42.
 The inventors here do not purport to have discovered that
 the “l” in “hello” requires a wider mouth shape than the “l”
 in “burly.”
      The second, and assertedly novel, aspect of the inven-
 tion, is a set of rules that tells the system how to automat-
 ically output the chosen mouth shapes in a format that can
 create an animation—as a continuous stream of morph
 weight sets that can transform a neutral model. See id.,
 col. 4, lines 46–60 (“The primary function of the rules is to
 determine[] 1) the appropriate morph weight set corre-
 spondence with each TAPT sub-sequence; and 2) the time
 parameters of the morph weight set transitions between
 the representation of the prior TAPT sub-sequence or other
 timed data and the current one.”). Because this process is
 the novel aspect of the claimed invention, the specification
 must reasonably teach how to make and use this aspect of
 the invention. See Auto. Techs., 501 F.3d at 1283; Genen-
 tech, 108 F.3d at 1366.
                               3
     The Developers have not, at this point in the case, met
 their burden of identifying a set of rules, for automatically
 outputting chosen mouth shapes, that is or may be within
 the scope of claim 1. See MagSil, 687 F.3d at 1380 (“A party
 must prove invalidity based on nonenablement by clear
 and convincing evidence.”).
     The district court identified, and relied on for the “more
 important[]” part of its analysis, two specific examples of-
 fered by Dr. Wyvill (the Developers’ expert): bones anima-
 tion (the accused product) and the BALDI system.
 Enablement Opinion at *12. As discussed above, bones an-
 imation uses 4x4 matrices or vectors of length sixteen to
 perform a combination of linear transformations on multi-
 ple vertices. J.A. 4649–50. Similarly, as the district court
 recognized, the BALDI system uses an “‘interlocking set of
 mathematical equations . . . that balance the influence of
Case: 19-1557    Document: 88       Page: 20    Filed: 05/20/2020




 20                MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



 different proximate phonemes on various aspects of the
 model’s facial expression.’” Enablement Opinion at *12
 (citing J.A. 5891–92). Dr. Wyvill stated that the specifica-
 tion of the ’278 patent does not “even remotely suggest that
 the inventor had possession of the species of rule sets that
 defines a morph weight set stream as a function of pho-
 neme sequence and time for bone animation,” J.A. 5893,
 and that the “BALDI system provides a good example of a
 system that uses ‘rules’ that are far more complex and in-
 tricate than anything the ’278 Patent describes,” J.A. 5891.
 The district court concluded that those statements “suggest
 that at the time of the invention, a person of skill in the art
 would not have the tools to practice the full scope of the
 ‘first set of rules’ limitation.” Enablement Opinion at *12.
     Given our construction of the term “morph weight
 sets,” however, both bones animation and the BALDI sys-
 tem are clearly “outside the scope of the claims” and are
 thus “irrelevant to enablement.” See Durel, 256 F.3d at
 1307. With respect to bones animation, our noninfringe-
 ment decision compels this conclusion—“bones” are not,
 and do not use, three-dimensional geometric vectors to
 move vertices. See supra pp. 10–13; see also Brief for Ap-
 pellee at 15 (“Bone transform values . . . do not specify, or
 even contain enough information to derive, the position or
 the displacement of any vertex on any facial model.”). Rec-
 ord evidence compels the same conclusion with respect to
 the BALDI process, at least in the context of a summary-
 judgment motion. Dr. Wyvill, in the context of an expert
 opinion regarding obviousness, conceded that BALDI’s “pa-
 rameter target values corresponding to each phoneme do
 not represent delta sets as construed” and that BALDI’s
 equations “do not represent the displacements of each ver-
 tex in terms of a simple xyz displacement vector.” J.A.
 5839.
Case: 19-1557     Document: 88       Page: 21      Filed: 05/20/2020




 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA                      21



                                 4
     Without bones animation and the BALDI process avail-
 able as claim-covered techniques that must be enabled, the
 district court’s reasoning is too abstract and too conclusory
 to support summary judgment.
       Apart from its discussion of bones and BALDI, the dis-
 trict court made two basic observations. First, the court
 noted, the “first set of rules” limitation “is broad, encom-
 passing more than simply a rule scheme that involves rules
 applied at keyframes or rules in the form of ‘if . . . then . . .
 else’ constructs.” Enablement Opinion at *8. Second, the
 court stated, a “review of the specification supports the con-
 clusion that the patent disclosure only provides working
 examples of rules related to a keyframe approach using an
 ‘if . . . then . . . else’ construct.” Id. at *10. Tying these two
 observations together, the court concluded that McRO had
 failed to “provide . . . any exemplary metric that might al-
 low the [c]ourt to understand the exact bounds of what is
 claimed in the ’278 Patent as a first set of rules.” Id. at *11.
 Accordingly, McRO could not “avoid an enablement chal-
 lenge by simply arguing that [the Appellees] ha[d] failed to
 identify an operative alternative embodiment.” Id.
     But these observations merely state the conclusion
 that the claims are too broad and the specification’s discus-
 sion is too narrow. The observations do not justify the con-
 clusion with any concrete support. To say that the “first
 set of rules” limitation is broader than “if . . . then . . . else”
 statements based on keyframes is not to say what else is or
 may be within the phrase—and it was the burden of the
 Developers, not McRO, to prove that such specific content
 exists and that it is not enabled. Where, as here, there is
 at least some expert testimony supporting enablement,
 even if at a high level of generality, see, e.g., J.A. 4893–94,
 J.A. 4944–47, the district court’s reasoning and the support
 offered by the Developers are not enough to justify sum-
 mary judgment of nonenablement for the Developers.
Case: 19-1557      Document: 88        Page: 22   Filed: 05/20/2020




 22                 MCRO, INC.   v. BANDAI NAMCO GAMES AMERICA



      We see no reason in this case to depart from our usual
 requirement that the challenger identify specifics that are
 or may be within the claim but are not enabled. Specifics
 have always mattered. See supra pp. 16–17. Here, a “fuller
 set of fact-findings [about what is] within the scope of the
 claims” is necessary “to decide the enablement issue.” Du-
 rel, 256 F.3d at 1307.
                                 III
      We affirm the district court’s judgment that the Devel-
 opers did not infringe the ’278 patent. We vacate the dis-
 trict court’s judgment that the Developers were entitled to
 summary judgment that the ’278 patent is invalid for lack
 of enablement. Without holding that the Developers could
 not make such a showing, we remand the case for such fur-
 ther proceedings as are appropriate, considering the Devel-
 opers’ offer to withdraw their invalidity counterclaims. 4
       The parties shall bear their own costs.
      AFFIRMED IN PART, VACATED IN PART, AND
                    REMANDED




       4We deny McRO’s request to direct that the case be
 assigned to a different district judge on remand. See Juicy
 Whip, Inc. v. Orange Bang, Inc., 382 F.3d 1367, 1371, 1373–
 74 (Fed. Cir. 2004).
