CLO Virtual Fashion Inc v. Zhejiang Lingdi Digital Technology Co Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: CLO Virtual Fashion Inc. (South Korea)
  • Defendant: Zhejiang Lingdi Digital Technology Co., Ltd. (d/b/a Linctex) (People's Republic of China)
  • Plaintiff's Counsel: Fenwick & West LLP
• Case Identification: 2:23-cv-00274, E.D. Tex., 06/14/2023
• Venue Allegations: Venue is alleged to be proper because the Defendant is not a resident of the United States, and thus may be sued in any judicial district.
• Core Dispute: Plaintiff alleges that Defendant's Style3D Studio software for 3D garment design infringes three U.S. patents related to virtual sewing and pattern measurement technologies.
• Technical Context: The technology at issue resides in the field of 3D computer-aided design for the fashion industry, focusing on software tools that simulate the process of sewing and measuring virtual clothing patterns.
• Key Procedural History: The complaint alleges a history of misappropriation, claiming Defendant used unlicensed "cracked" versions of Plaintiff's software to develop its competing product. It also references legal proceedings initiated by the Plaintiff in China, which resulted in a court-authorized raid on Defendant's offices on May 10, 2023, to collect evidence. Plaintiff allegedly provided Defendant with notice of the patents-in-suit on June 7, 2023.

Case Timeline

Date	Event
2015-04-27	Priority Date for '773 and '355 Patents
2019-08-19	Priority Date for '448 Patent
2020-08-04	'773 Patent Issued
2021-03-02	Date of Defendant's alleged Facebook advertisement
2022-01-11	'448 Patent Issued
2022-08-09	'355 Patent Issued
2023-05-10	Court-authorized raid on Defendant's offices in China
2023-06-07	Plaintiff sends infringement notice letter to Defendant
2023-06-13	Defendant's Chief Science Officer receives letter
2023-06-13	Defendant refuses FedEx delivery of letter at headquarters
2023-06-14	Defendant accepts FedEx delivery of letter at headquarters
2023-06-14	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,733,773 - "Method and apparatus for creating digital clothing" (Issued Aug. 4, 2020)

The Invention Explained

• Problem Addressed: The patent addresses inefficiencies in "free sewing" features within 3D clothing design software Compl. ¶42 In free sewing, users have the autonomy to define seam lines of arbitrary length, but this creates a burden: the user must manually ensure that two segments intended to be sewn together are of equal length Compl. ¶43 Failure to do so accurately can result in a compromised virtual garment with unrealistic wrinkles or stretching '773 Patent, col. 1:43-49
• The Patented Solution: The invention is a software method that assists the user during the free sewing process Compl. ¶45 When a user defines a first seam segment, and then moves to define the corresponding second segment, the system automatically detects the cursor's position and displays a "candidate ending point" on the second pattern piece '773 Patent, col. 2:32-41 This candidate point is calculated to make the length of the second segment "substantially equal" to the first, thereby guiding the user to create a perfectly matched seam with minimal effort '773 Patent, abstract The system can also display the numerical difference in lengths and provide a warning if the disparity is too large '773 Patent, col. 2:55-65
• Technical Importance: This technology aims to improve the usability and efficiency of virtual garment creation by reducing manual adjustments and potential for user error in a core design task Compl. ¶54

Key Claims at a Glance

The complaint asserts at least independent claim 1 Compl. ¶76

• Claim 1 (method):
  • Setting a first selected segment to be sewn on a pattern.
  • Setting a second selected segment, which comprises inputting a starting point.
  • Detecting a current cursor position.
  • Displaying a candidate ending point on the second segment to make its length substantially equal to the first segment's length.
  • Connecting the starting point to a present point on the second segment (closest to the cursor) to form a line.
  • Moving the present point to the candidate ending point if the difference between them is less than a reference value.
  • Displaying a difference value between the first segment's length and the line's length.
  • Selecting the present point as the ending point in response to user input.
  • Setting the final second selected segment as the section between its starting and ending points.

U.S. Patent No. 11,410,355 - "Method and apparatus for creating digital clothing" (Issued Aug. 9, 2022)

The Invention Explained

• Problem Addressed: As a continuation of the application leading to the '773 patent, the '355 patent addresses the same technical problem: the difficulty and inefficiency of manually matching seam lengths in virtual "free sewing" Compl. ¶38 Compl. ¶¶43-44
• The Patented Solution: The solution is also a software-based user assistance tool. While sharing a common specification with the '773 patent, the claims of the '355 patent introduce a specific user interface enhancement: the use of color to provide immediate visual feedback '355 Patent, claim 1 The system displays the length and/or difference value in a first color when the seam lengths are "substantially equal," and in a second, different color when they are "substantially different" '355 Patent, col. 15:5-12
• Technical Importance: This feature provides an intuitive, at-a-glance visual cue to the designer about the status of the seam match, further streamlining the workflow and reducing the cognitive load on the user Compl. ¶54

Key Claims at a Glance

The complaint asserts at least independent claim 1 Compl. ¶99

• Claim 1 (method):
  • Setting a first selected segment to be sewn.
  • Setting a second selected segment, which includes setting a start point, determining a present point based on cursor position, moving the present point to a candidate ending point, selecting the end point via user input, and setting the final segment.
  • A key distinction is the added limitation: "wherein, when the second length is substantially equal to the first length, at least one of the... length and a difference value... is displayed in a first color".
  • And a further limitation: "wherein, when the second length is substantially different from the first length, at least one of the... length and the difference value is displayed in a second color, the second color being different from the first color".

U.S. Patent No. 11,222,448 - "Method and apparatus for measuring measurement of two-dimensional pattern corresponding to three-dimensional virtual clothing" (Issued January 11, 2022)

• Technology Synopsis: The patent addresses the problem that measuring a distance on a 3D virtual garment can be inaccurate because the fabric may be stretched, folded, or draped, distorting the true length found on the original 2D flat pattern Compl. ¶58 The invention provides a method to measure lengths directly on the 2D pattern, including a system for measuring a line segment that spans across two or more separate 2D pattern pieces, accounting for the space between them '448 Patent, col. 2:8-15
• Asserted Claims: The complaint asserts at least independent claim 1 Compl. ¶120
• Accused Features: The "Point to Point Measure" function in the accused Style3D software is alleged to infringe this patent Compl. ¶121

III. The Accused Instrumentality

Product Identification

• The accused instrumentality is Defendant's virtual design program, Style3D Studio ("Style3D") Compl. ¶67

Functionality and Market Context

• Style3D is software for 3D digital clothing design and cloth simulation, marketed to fashion designers and enterprises Compl. ¶10 Compl. ¶67 The complaint focuses on two specific features:
  1. "Free Sewing" mode: This tool allows users to define and sew together segments on 2D patterns Compl. ¶79
  2. "Point to Point Measure" function: This tool allows users to measure distances on 2D patterns, including across separate pattern pieces Compl. ¶121 Compl. ¶123
• The complaint alleges that Style3D is a "knock-off" product developed by a direct competitor Compl. ¶31 It further alleges that Defendant used more than 50 unlicensed, "cracked" versions of Plaintiff's own software in its research and development to create Style3D Compl. ¶23 Compl. ¶24 One screenshot in the complaint shows Style3D's user interface for selecting a pattern piece to begin a sewing operation Compl. p. 22, Figure 1 Another screenshot shows Style3D's interface for the "Point to Point Measure" function being used on a 2D shirt pattern Compl. p. 40, Figure 17

IV. Analysis of Infringement Allegations

U.S. Patent No. 10,733,773 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
[a] setting a first selected segment by inputting the first selected segment to be sewn on a first segment on a pattern	In "Free Sewing" mode, the user selects a segment on a first pattern piece (e.g., a rectangular fabric piece) to define the first seam line.	¶79	col. 4:36-44
[b] setting a second selected segment, comprising [b.1] inputting a starting point of the second selected segment on a second segment...	The user then inputs a starting point for the corresponding seam on a second pattern piece (e.g., a trapezoid-shaped fabric piece).	¶80; ¶81	col. 5:46-54
[d] displaying a point on the second segment as a candidate ending point of the second selected segment to make a length of the second selected segment substantially equal to a length of the first...	As the user moves the cursor along the second pattern piece, Style3D displays a candidate ending point (identified as a blue dot) that would make the length of the second segment equal to the first. The complaint includes a screenshot showing this candidate point where the displayed length difference is "0.00" Compl. p. 25, Figure 6	¶83	col. 6:34-46
[f] moving the present point to the candidate ending point, in response to the difference between the present point and the candidate ending point being less than a second reference value	The complaint alleges that the software causes the cursor's present point (the blue dot) to "snap to" the candidate end point when it is within a certain proximity, satisfying this "moving" step.	¶85	col. 6:47-56
[g] displaying a difference value between the length of the first selected segment and a length of the line	Style3D allegedly displays the lengths of both the first and second segments, as well as the numerical difference between them, in the format N.NN (XX.XX, YY.YY).	¶86	col. 7:6-14
[h] selecting the present point as an ending point of the second selected segment, in response to a user input	The user finalizes the seam by making a mouse click, which selects the present point as the end point for the second segment. The complaint shows a screenshot where the selected line turns orange to indicate selection Compl. p. 26, Figure 7	¶87	col. 7:21-24

Identified Points of Contention ('773 Patent)

• Scope Questions: A potential issue is the meaning of "moving the present point." The claim requires the system to move the point to the candidate ending point. The dispute may focus on whether the alleged "snap to" functionality Compl. ¶85 constitutes the system performing this "moving" step, or if it is merely a user-guidance feature that does not meet the limitation's active requirement.
• Technical Questions: The complaint's allegations rely on observations of the software's user interface. A factual question will be what evidence demonstrates that the underlying software logic performs the specific sequence of steps recited in claim 1, such as connecting points to form a line "based on a difference between the current cursor position and the present point being less than a first reference value."

U.S. Patent No. 11,410,355 Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
[a] setting a first selected segment to be sewn on a first segment on a pattern	In "Free Sewing" mode, a user selects a segment on a pattern piece to serve as the first seam.	¶101	col. 4:36-44
[b.3] moving the present point to a candidate ending point... wherein the candidate ending point is determined to make a second length of the second selected segment substantially equal to a first length...	The software displays a candidate ending point (identified by a blue dot) that makes the second segment length equal to the first, as shown by a "0.00" difference value. The complaint alleges the system moves the present point to this candidate point.	¶105	col. 6:34-46; col. 6:47-56
[b.6] wherein, when the second length is substantially equal to the first length, at least one of the first length, the second length and a difference value... is displayed in a first color	The complaint alleges that when the difference between the segment lengths is less than a reference value (i.e., they are substantially equal), the difference value is displayed in blue. A screenshot is provided to illustrate this functionality Compl. p. 36, Figure 16	¶108; ¶109	col. 15:5-9
[b.7] wherein, when the second length is substantially different from the first length, at least one of the first length, the second length and the difference value is displayed in a second color...	The complaint alleges that Style3D displays the difference value as a "warning sign" in red when the difference is greater than a reference value. The complaint provides a screenshot showing the numerical difference value displayed in red text when the lengths do not match Compl. p. 35, Figure 15	¶108; ¶109	col. 15:9-12

Identified Points of Contention ('355 Patent)

• Scope Questions: The interpretation of "substantially equal" and "substantially different" will be central. The dispute will likely revolve around whether these terms require a specific numerical threshold and whether the accused product's color-changing logic meets that definition. The complaint alleges a change from red to blue, which appears to map directly to the "first color" and "second color" limitations.
• Technical Questions: The case may turn on evidence of the specific reference values or thresholds used by Style3D to trigger the change in color. Discovery into the source code or internal design documents of the accused product could be pivotal in determining whether its operation aligns with the claim limitations.

V. Key Claim Terms for Construction

• From the '773 and '355 Patents:

  • The Term: "moving the present point to the candidate ending point"
  • Context and Importance: This term is critical because it defines an automated action performed by the system. The infringement analysis will depend on whether the accused Style3D software's "snap to" feature constitutes the system itself "moving" the point, as opposed to merely suggesting a location for the user to manually move the cursor to. Practitioners may focus on this term because it distinguishes a passive guidance tool from an active, automated adjustment system.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent's overall purpose is to assist the user and improve usability '773 Patent, col. 1:59-62 This context could support an interpretation where any system-driven cursor behavior that places the point at the candidate location, even if initiated or confirmed by the user, meets the "moving" requirement.
    • Evidence for a Narrower Interpretation: The claim language recites "moving the present point... in response to the difference... being less than a second reference value" '773 Patent, claim 1 This suggests a specific, conditional, and automated software action, not just a passive visual guide. The flowchart in Figure 2 of the patent shows "MOVE CURSOR POSITION" as a distinct system step (S25), which could support a narrower reading requiring full system control over the movement.

• From the '355 Patent:

  • The Term: "substantially equal" / "substantially different"
  • Context and Importance: These terms are the direct trigger for the claimed color-changing feature. Their construction will determine the scope of infringement, as the definition will dictate the conditions under which the accused product must change colors to infringe. The definiteness of these terms may also be a focus.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification does not appear to provide a precise numerical definition for "substantially," which may suggest the term should be given its ordinary meaning in the art, possibly allowing for a small tolerance or range of values rather than absolute identity.
    • Evidence for a Narrower Interpretation: Figure 7 of the common specification shows an example where the lengths are equal and the displayed difference value is exactly "0.00" '355 Patent, FIG. 7 This embodiment could be used to argue that "substantially equal" means numerically identical or extremely close to it, and "substantially different" means any non-zero difference.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement for all three patents. Inducement is based on allegations that Linctex provides instructions and tutorials on its website that teach users how to use Style3D's features in an infringing manner Compl. ¶89 Compl. ¶110 Compl. ¶126 Contributory infringement is based on the allegation that the Style3D software is especially made for infringing use and has no substantial non-infringing uses Compl. ¶90 Compl. ¶111 Compl. ¶127
• Willful Infringement: Willfulness is alleged for all three patents based on Defendant's alleged knowledge of the patents since at least June 7, 2023, following receipt of a notice letter from Plaintiff Compl. ¶93 Compl. ¶114 Compl. ¶130 The complaint notes that Defendant's continued infringement after this date was willful and deliberate.

VII. Analyst's Conclusion: Key Questions for the Case

• A core issue will be one of technical operation: For the '773 and '355 patents, does the accused "snap to point" feature in Style3D's "Free Sewing" mode perform the active step of "moving" the cursor as required by the claims, or does it function as a passive user guide? The case will likely require a deep dive into the software's functionality to determine if its operational logic matches the claimed sequence of steps.
• A second key question will be one of algorithmic correspondence: For the '448 patent, does the accused "Point to Point Measure" tool's method for calculating length across two separate 2D patterns meet the claimed limitations of "determining attributes of areas" and then changing the length "to account for separation"? The dispute may center on whether the underlying algorithm in Style3D performs a function equivalent to that described and claimed in the patent.
• An overarching evidentiary question will be the impact of the alleged misappropriation: The complaint's detailed allegations of copying, including the use of "cracked" software and a court-ordered raid in China, create a powerful narrative. The extent to which evidence from these events is admissible and persuasive could significantly influence the analysis of intent, particularly for the claims of willfulness and indirect infringement.