Artistic techniques for generating line drawings

Abstract

Generating a line drawing includes receiving scene data, including the position of a camera that captures the scene data; calculating a 3D mesh of the scene data; calculating a camera angle relative to the 3D mesh using the camera's position; analyzing the scene data and analyzing the position of potential lines based on the camera angle relative to the 3D mesh; generating a base curve for the position of the potential lines; and generating a stylized curve by generating quadratic lines on the base curve based on user input.

Description

Technical Field

[0001] 〔Cross - Reference to Related Applications〕

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63 / 511,085, entitled "Artistic driven Approach to Linework Generation," filed on June 29, 2023. The disclosure of the above - related application is incorporated herein by reference.

[0002]

[0002] This disclosure relates to line drawing generation, and more particularly, to an artistic approach to line drawing generation in animation.

Background Art

[0003]

[0003] In the production of movies with a world rooted in the comic - book style, the importance of incorporating line drawings can be indispensable. Due to the significantly increased demand for line drawings, lines are applied throughout both characters and the environment. Therefore, an efficient method is needed to preserve the line - drawing style and batch - process the generation of line drawings with minimal effort.

Summary of the Invention

Problems to be Solved by the Invention

[0004]

[0004] This disclosure implements techniques for line drawing generation.

Means for Solving the Problems

[0005]

[0005] One implementation discloses a method for generating line drawings. The method includes the steps of: receiving scene data including the position of a camera that captures the scene data; calculating a 3D mesh of the scene data; calculating a camera angle relative to the 3D mesh using the position of the camera; analyzing the scene data and analyzing the positions of potential lines based on the camera angle relative to the 3D mesh; generating a base curve for the positions of the potential lines; and generating a stylized curve by generating quadratic lines on the base curve based on user input.

[0006]

[0006] Another implementation discloses a system for generating line drawings. The system is a processor for receiving scene data and calculating a 3D mesh, comprising: a processor for calculating a camera angle relative to the 3D mesh using camera positions included in the scene data; an analysis unit for analyzing the scene data and analyzing the positions of potential lines based on the camera angles relative to the 3D mesh; a base curve generation unit for generating a base curve for the positions of the potential lines; and a secondary line generation unit for generating secondary lines on the base curve based on user input to generate a stylized curve.

[0007]

[0007] Further implementations disclose a non-temporary computer-readable storage medium for storing a computer program for generating line drawings. The computer program includes executable instructions which cause the computer to: receive the scene data, including the position of a camera that captures the scene data; calculate a 3D mesh of the scene data; use the position of the camera to calculate a camera angle relative to the 3D mesh; analyze the scene data and analyze the positions of potential lines based on the camera angle relative to the 3D mesh; generate a base curve for the positions of the potential lines; and generate a stylized curve by generating quadratic lines on the base curve based on user input.

[0008]

[0008] Other features and advantages will also become apparent from this specification, which illustrates aspects of the present disclosure as examples.

[0009]

[0009] By examining the attached drawings in which the same parts are shown by the same reference numerals, the details of this disclosure can be partially gathered with respect to both its structure and operation. [Brief explanation of the drawing]

[0010] [Figure 1] This is a flowchart of a line drawing generation method using one implementation of the disclosed method. [Figure 2A] This figure shows an example of the original geometry of a 3D mesh. [Figure 2B] This figure shows an example of a base curve generated for the position of a potential line. [Figure 2C] This figure shows an example of a rendered, stylized curve. [Figure 3] This figure shows an example of interpolation techniques for combining hand-drawn lines with curves generated by a line drawing generation method. [Figure 4] This figure shows a dual-rest redrawing technique based on one implementation of the present disclosure. [Figure 5A] This figure shows a character divided into multiple parts based on screen-space angular velocity. [Figure 5B] This figure shows an analysis of the activities in each partition. [Figure 6] This is a block diagram of the line drawing generation unit according to one implementation of the present disclosure. [Figure 7A] This is a diagram of a computer system and user implemented in this disclosure. [Figure 7B] This is a functional block diagram showing a computer system that hosts a line drawing generation application implemented in this disclosure. [Modes for carrying out the invention]

[0011]

[0021] As described above, there is a need for an efficient method of saving a line drawing style and efficiently batch-processing the generation of line drawings with minimal effort.

[0012]

[0022] Certain implementations of the present disclosure provide an artistic approach to line drawing generation. After reading the following description, the implementation methods of the present disclosure in various implementations and applications will become apparent. Although various implementations of the present disclosure are described herein, it should be understood that these implementations are presented by way of example only and not by way of limitation. Therefore, the detailed description of various implementations should not be construed as limiting the scope or extension of the present disclosure.

[0013]

[0023] Features provided in various implementations for an artistic approach to line drawing generation can include the following.

[0014]

[0024] (a) Advanced artistic control for fine-tuning the appearance of lines while each world and character has its own line drawing style.

[0015]

[0025] (b) Hand-drawn style line drawings that spread beyond the surface for characters with a messy appearance.

[0016]

[0026] (c) Persuasive redrawing of line drawings by dynamic updates rather than remaining static geometrically.

[0017] <0%000094> (d) Synchronizing line drawing animations with the step-by-step timing of character animations.

[0018]

[0028] (e) An efficient method of saving a line drawing style and batch-processing the generation of line drawings with minimal effort.

[0019]

[0029] (f) The ability to combine hand-drawn line drawings and procedurally generated line drawings.

[0020]

[0030] Figure 1 is a flowchart of a line drawing generation method 100 according to one implementation of the present disclosure.

[0021]

[0031] In the implementation shown in Figure 1, in step 110, the scene data is first received and a 3D mesh is calculated. The scene data also includes the position of the camera capturing the scene. Next, in step 120, the camera angle relative to the 3D mesh is calculated. In step 130, the scene data is analyzed and the position of potential lines is analyzed based on the camera angle relative to the 3D mesh. Next, in step 140, a base curve is generated for the position of potential lines.

[0022]

[0032] In one implementation, step 150 checks whether the base curve lacks visual consistency. If visual consistency is lacking, step 160 generates a set of multiple base curves that should fade in and fade out to ensure visual consistency from the camera viewpoint. In one implementation, step 160, which generates a set of base curves that should fade in and fade out to ensure visual consistency, also includes recalculating the camera angle relative to the 3D mesh (step 120).

[0023]

[0033] In one implementation, in step 170, a quadratic curve is generated on top of the base curve based on user input to produce a stylized curve. In some implementations, "stylized" quadratic curves mean that various properties such as tapering and offsets are assigned to them to achieve a complex but natural appearance. Next, in step 180, the stylized curve is rendered.

[0024]

[0034] Figures 2A to 2C show examples of the original 3D mesh, base curve, and rendered stylized curve.

[0025]

[0035] Figure 2A shows an example of the original geometry of a 3D mesh.

[0026]

[0036] Figure 2B shows an example of a base curve generated for the position of a potential line.

[0027]

[0037] Figure 2C shows an example of a rendered, stylized curve.

[0028]

[0038] The line art generation method in Figure 1 produced convincing line art, but it was determined that better results could sometimes be obtained by combining this method with hand-drawn lines. In some implementations, drawings were created using Blender and exported to Houdini. In other implementations, vector data was exported from a digital content creation application. These sets of drawings were then interpolated and merged with the curves generated by the line art generation method.

[0029]

[0039] Figure 3 shows an example of interpolation technique 300 for combining hand-drawn lines and curves generated by a line drawing generation method. In the implementation shown in Figure 3, lines drawn in frames 310, 320, 330, 340, 350, and 360 are interpolated and merged between frames. Enlarged view 332 between frame 330 and frame 340 shows the details of the interpolation and merging process.

[0030]

[0040] Referring to enlarged figure 332, a fading-out line moves forward in time along with the geometry onto which it is projected, while the opacity of the line decreases, the line tapers, or both. Enlarged figure 332 also shows that a fading-in line starts from the position on which it is projected, and as the line fades in, it is advected backward in time along the geometry, again using opacity and tapering to reveal the line.

[0031]

[0041] In one implementation, combining the generated line drawings with animation adds further complexity. Therefore, in the animation, when a line is "drawn," the curve gradually reveals its opacity, like an invisible pencil drawing a line on paper. Similarly, when a line is "erased," the curve loses its opacity as if being gradually wiped away. The rate at which this process (i.e., both the appearance and erasure of lines) occurs is known as the "redraw rate." In some implementations, the line is tapered from one end to the other rather than adjusting its opacity.

[0032]

[0042] In some implementations, determining the optimal "redraw speed" can be difficult. For example, a high redraw speed can be distracting when a character is relatively stationary. Conversely, setting the redraw speed too low for a moving character can cause lines to freeze on the model, resulting in contour issues where the outline may appear detached from the silhouette. To address these issues, a "dual rest" technique can be used.

[0033]

[0043] Figure 4 shows a dual-rest redrawing technique 400 according to one implementation of the present disclosure. In the implementation shown in Figure 4, two line sets 410 and 420 work in conjunction, with one set (e.g., line set 1 - solid lines) being "drawn" while the other set (e.g., line set 2 - dashed lines) is "erased," and vice versa. It was determined that by setting appropriate redrawing speeds for the two line sets 410 and 420, a natural-looking line drawing update can be obtained.

[0034]

[0044] Further implementations have taken the dual-rest redraw concept to the next level by creating a system that automatically detects the degree of change in character performance. This new system establishes an appropriate redraw rate across different parts of the character. In other words, it automatically divides the character area based on movement in screen space and places parts of the body that move together in the same partition.

[0035]

[0045] Figures 5A and 5B show an example of dividing character regions based on screen space movement in one implementation of the present disclosure.

[0036]

[0046] Figure 5A shows a character divided into multiple parts based on screen-space angular velocity.

[0037]

[0047] Figure 5B shows an analysis of the activities in each partition.

[0038]

[0048] In the example shown in Figure 5A, only the character's left arm 500 shows movement, while the remaining part 502 shows little to no movement. Therefore, during the period when movement of the left arm is detected, the redrawing of part 502 results in a slow-moving graph 510 (upper graph in Figure 5B), while the redrawing of part 500 results in a fast-moving graph 520 (lower graph in Figure 5B). In both graphs in Figure 5B, the dotted curves 512 and 522 quantify the speed of movement, and the solid and dashed curves 514, 516, 524, and 526 are sets of lines to be drawn / erased (as shown in Figure 4).

[0039]

[0049] In further implementations, the techniques shown in Figures 5A and 5B can be extended to groups of objects that move together in screen space, such as vehicles on a highway or props in a room.

[0040]

[0050] Figure 6 is a block diagram of a line drawing generation system 600 according to one implementation of the present disclosure. In the implementation shown in Figure 6, the system 600 includes a processor 610, an analysis unit 620, a base curve generation unit 630, a secondary line generation unit 640, and a visual consistency generation unit 650.

[0041]

[0051] In one implementation, the processor 610 receives scene data 660 and calculates a 3D mesh. The processor 610 also uses the camera position included in the scene data to calculate the camera angle relative to the 3D mesh. The analysis unit 620 analyzes the scene data and analyzes the position of potential lines based on the camera angle relative to the 3D mesh. The base curve generation unit 630 generates a base curve for the position of the potential lines.

[0042]

[0052] In one implementation, the visual consistency generator 650 determines whether the base curve lacks visual consistency. If visual consistency is lacking, the base curve generator 630 generates a set of multiple base curves that should fade in and fade out to ensure visual consistency from the camera viewpoint. In one implementation, generating a set of base curves includes recalculating the camera angle relative to the 3D mesh.

[0043]

[0053] In one implementation, the secondary line generation unit 640 generates a secondary line on top of the base curve based on user input, thereby generating a stylized curve. In some implementations, "stylized" secondary lines mean that various characteristics such as different taperings and offsets are assigned to achieve a complex but natural appearance. The secondary line generation unit 640 transmits the generated stylized curve to the visual consistency generation unit 650. In some implementations, "stylized" secondary lines mean that various characteristics such as different taperings and offsets are assigned to achieve a complex but natural appearance.

[0044]

[0054] In one implementation, the line art generation system 600 also includes a combiner 680 that combines a set of stylized curves and hand-drawn sketches. Furthermore, the combiner 680 may include interpolating the hand-drawn sketches and merging them with the curves generated by the line art generation method. Visually consistent stylized curves can be rendered by any general-purpose renderer 670.

[0045]

[0055] In one implementation, steps 110-180 and blocks 610-650 are comprised entirely of hardware including one or more digital signal processors (DSPs), general-purpose microprocessors, application-specific integrated circuits (ASICs), field-programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. One implementation includes one or more programmable processors and corresponding computer system components, which store and execute computer instructions to provide the operation of the wallet infrastructure at, for example, the user level and the provider level (providers of products, assets, content, etc.).

[0046]

[0056] Figure 7A shows a computer system 700 and user 702 according to an implementation of the present disclosure. User 702 uses the computer system 700 to implement an application 790 for line drawing generation with respect to process 100 in Figure 1 and system 600 in Figure 6.

[0047]

[0057] The computer system 700 stores and executes the line drawing generation application 790 shown in Figure 7B. Furthermore, the computer system 700 can communicate with a software program 704. The software program 704 may contain software code for the line drawing generation application 790. The software program 704 can be loaded onto an external medium such as a CD, DVD, or storage drive, as will be further described below.

[0048]

[0058] Furthermore, the computer system 700 can be connected to the network 780. The network 780 can be connected in various different architectures, such as a client-server architecture, a peer-to-peer network architecture, or other types of architectures. For example, the network 780 can communicate with a server 785 that coordinates the engine and data used within the line drawing generation application 790. Also, the network can be of different types. For example, the network 780 can be the Internet, a local area network or any variation of a local area network, a wide area network, a metropolitan area network, an intranet or extranet, or a wireless network.

[0049]

[0059] Figure 7B is a functional block diagram showing a computer system 700 hosting a line drawing generation application 790 according to an implementation of the present disclosure. The controller 710 is a programmable processor that controls the operation of the computer system 700 and its components. The controller 710 loads instructions (for example, in the form of computer programs) from memory 720 or built-in controller memory (not shown), executes these instructions to control the system, and provides, for example, data processing. In its execution, the controller 710 provides a software system to the line drawing generation application 790. Alternatively, this service can be implemented as a separate hardware component in the controller 710 or the computer system 700.

[0050]

[0060] Memory 720 temporarily stores data for use by other components of the computer system 700. In one implementation, memory 720 is implemented as RAM. In another implementation, memory 720 also includes long-term or permanent memory such as flash memory and / or ROM.

[0051]

[0061] The storage 730 stores data temporarily or for extended periods for use by other components of the computer system 700. For example, the storage 730 stores data used by the line drawing generation application 790. In one implementation, the storage 730 is a hard disk drive.

[0052]

[0062] The media device 740 accepts removable media and reads and / or writes data to the inserted media. In one implementation, for example, the media device 740 is an optical disc drive.

[0053]

[0063] The user interface 750 includes components for receiving user input from the user of the computer system 700 and presenting information to the user 702. In one implementation, the user interface 750 includes a keyboard, mouse, audio speakers, and a display. In another implementation, the user interface 750 also includes a headset worn by the user and used to collect eye movements as user input. The controller 710 uses input from the user 702 to coordinate the operation of the computer system 700.

[0054]

[0064] The I / O interface 760 includes one or more I / O ports and connects to corresponding I / O devices such as external storage or supplementary devices (e.g., printers or PDAs). In one implementation, the ports of the I / O interface 760 include ports such as USB ports, PCMCIA ports, serial ports, and / or parallel ports. In another implementation, the I / O interface 760 includes a wireless interface for wireless communication with external devices.

[0055]

[0065] Network interface 770 includes wired and / or wireless network connections such as RJ-45 or “Wi-Fi” interfaces (including, but not limited to, 802.11) that support Ethernet connectivity.

[0056]

[0066] Computer system 700 includes additional hardware and software typical of a computer system (e.g., power, cooling, operating system), but these components are not specifically shown in Figure 7B for the sake of simplification. Other implementations may use different configurations of the computer system (e.g., different bus or storage configurations or multiprocessor configurations).

[0057]

[0067] The descriptions herein of the disclosed implementations are provided so that a person skilled in the art can implement or utilize this disclosure. A number of modifications to these implementations will be readily apparent to a person skilled in the art, and the principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the implementations shown herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein. Accordingly, additional modifications and implementations are possible.

[0058]

[0068] One particular implementation discloses a method for generating line drawings. The method includes the steps of: receiving scene data including the position of a camera that captures the scene data; calculating a 3D mesh of the scene data; calculating a camera angle relative to the 3D mesh using the position of the camera; analyzing the scene data and analyzing the positions of potential lines based on the camera angle relative to the 3D mesh; generating a base curve for the positions of the potential lines; and generating a stylized curve by generating quadratic lines on the base curve based on user input.

[0059]

[0069] In one implementation, the step of generating the stylized curve includes assigning properties to achieve a natural appearance. In one implementation, the properties include various taperings and offsets. In one implementation, the method further includes the step of determining whether the base curve lacks visual consistency. In one implementation, the method further includes the step of generating a set of multiple base curves and fading them in and out when the base curve lacks visual consistency. In one implementation, the method further includes the step of rendering the stylized curve. In one implementation, the method further includes the step of adding hand-drawn lines to the stylized curve. In one implementation, the step of adding hand-drawn lines includes exporting vector data from a digital content creation application to generate a set of drawings. In one implementation, the method further includes the step of interpolating the set of drawings and merging them with the stylized curve.

[0060]

[0070] Another specific implementation discloses a system for generating line drawings. The system includes a processor for receiving scene data and calculating a 3D mesh, the processor for calculating a camera angle relative to the 3D mesh using camera positions included in the scene data; an analysis unit for analyzing the scene data and analyzing the positions of potential lines based on the camera angle relative to the 3D mesh; a base curve generation unit for generating a base curve for the positions of the potential lines; and a secondary line generation unit for generating secondary lines on the base curve based on user input to generate a stylized curve.

[0061]

[0071] In one implementation, the secondary line generator generates the stylized curve by assigning characteristics to achieve a natural appearance. In one implementation, the assigned characteristics include various taperings and offsets. In one implementation, the system further includes a visual consistency generator for determining whether the base curve lacks visual consistency, and the base curve generator generates a set of base curves, fading them in and out when the base curve lacks visual consistency. In one implementation, the system further includes a combiner for adding a set of hand-drawn illustrations to the stylized curve. In one implementation, the combiner generates a set of illustrations by exporting vector data from a digital content creation application. In one implementation, the combiner further interpolates the set of illustrations and merges them with the stylized curve.

[0062]

[0072] In yet another specific implementation, a non-temporary computer-readable storage medium is disclosed for storing a computer program for generating line drawings. The computer program includes executable instructions which cause the computer to: receive the scene data, including the position of a camera capturing the scene data; calculate a 3D mesh of the scene data; use the position of the camera to calculate a camera angle relative to the 3D mesh; analyze the scene data and analyze the positions of potential lines based on the camera angle relative to the 3D mesh; generate a base curve for the positions of the potential lines; and generate a stylized curve by generating quadratic lines on the base curve based on user input.

[0063]

[0073] In one implementation, the executable instructions causing the computer to generate the stylized curve include executable instructions causing the computer to assign characteristics including various taperings and offsets. In one implementation, the non-temporary computer-readable storage medium further includes executable instructions causing the computer to generate a set of multiple base curves and fade them in and out when the base curve lacks visual consistency. In one implementation, the non-temporary computer-readable storage medium further includes executable instructions causing the computer to add hand-drawn lines to the stylized curve, export vector data from a digital content creation application to generate a set of drawings, interpolate the set of drawings and merge them with the stylized curve.

[0064]

[0074] Not all features of each of the embodiments described above are necessarily required in any particular implementation of the Disclosure. Furthermore, the descriptions and drawings presented herein should be understood to represent the subject matter broadly intended by this Disclosure. Moreover, the scope of this Disclosure fully includes other implementations that may be apparent to those skilled in the art, and therefore, the scope of this Disclosure should not be limited by anything other than the appended claims. [Explanation of Symbols]

[0065] 110 Receive scene data and calculate 3D mesh Calculate the camera angle for 120 3D meshes. Analyze 130 scene data and analyze the position of potential lines based on the camera angle relative to the 3D mesh. 140 Generate a base curve for the position of potential lines. 150. Is there a lack of visual consistency? 160 Generate a set of multiple base curves to fade in and fade out. 170 Based on user input, generate a quadratic curve on top of the base curve to create a stylized curve. 180 Rendering stylized curves 300 Interpolation Techniques 310, 320, 330, 340, 350, 360 frames 332 Enlarged view 400 Dual Rest Redraw Techniques 410,420 line set 500 Left-handed 502 Remaining part 600 Line Drawing Generation System 610 Processor 620 Analysis Department 630 Base curve generation unit 640 Secondary line generation section 650 Visual Consistency Generation Unit 660 Scene Data 670 Renderer 680 Combiner 700 Computer Systems 702 users 704 Software Programs 710 Controller 720 memory 730 storage 740 media devices 750 User Interfaces 760 I / O interfaces 770 Network Interfaces 780 Network 785 Servers 790 Line drawing generation application

Claims

1. A method for generating line drawings, The steps include receiving the scene data, which includes the position of the camera that captures the scene data, The steps include calculating the 3D mesh of the aforementioned scene data, A step of calculating the camera angle relative to the 3D mesh using the position of the camera, The steps include analyzing the scene data and analyzing the position of potential lines based on the camera angle relative to the 3D mesh, The steps include generating a base curve for the position of the potential line, The steps include generating a quadratic curve on the base curve based on user input to generate a stylized curve, A method characterized by including the following.

2. The method according to claim 1, characterized in that the step of generating the stylized curve includes assigning properties to achieve a natural appearance.

3. The method according to claim 2, characterized in that the aforementioned characteristics include various taperings and offsets.

4. The method according to claim 1, further comprising the step of determining whether the base curve lacks visual consistency.

5. The method according to claim 4, further comprising the step of generating a set of multiple base curves and fading them in and out when the base curve lacks visual consistency.

6. The method according to claim 1, further comprising the step of rendering the stylized curve.

7. The method according to claim 1, further comprising the step of adding hand-drawn lines to the stylized curve.

8. The method according to claim 7, characterized in that the step of adding hand-drawn lines includes exporting vector data from a digital content creation application to generate a set of drawings.

9. The method according to claim 8, further comprising the step of interpolating the set of drawings and merging them with the stylized curves.

10. A system for generating line drawings, A processor for receiving scene data and calculating a 3D mesh, comprising a processor for calculating the camera angle relative to the 3D mesh using the camera position included in the scene data, An analysis unit analyzes the aforementioned scene data and analyzes the position of potential lines based on the camera angle relative to the 3D mesh, A base curve generation unit for generating a base curve for the position of the potential line, A secondary line generation unit generates a secondary line on the base curve based on user input to generate a stylized curve, A system characterized by including

11. The system according to claim 10, characterized in that the secondary line generation unit generates the stylized curve by assigning characteristics to achieve a natural appearance.

12. The system according to claim 11, characterized in that the assigned characteristics include various taperings and offsets.

13. The system further includes a visual consistency generation unit for determining whether the base curve lacks visual consistency, The system according to claim 10, characterized in that the base curve generation unit generates a set of base curves and fades them in and out when the base curves lack visual consistency.

14. The system according to claim 10, further comprising a combiner for adding a set of hand-drawn illustrations to the stylized curve.

15. The system according to claim 14, characterized in that the combiner exports vector data from a digital content creation application to generate a set of drawings.

16. The system according to claim 15, wherein the combiner further interpolates the set of drawings and merges them with the stylized curves.

17. A non-temporary computer-readable storage medium for storing a computer program for generating line drawings, wherein the computer program includes executable instructions, and the executable instructions are transmitted to the computer. Receiving the scene data, including the position of the camera that captures the scene data, Calculating the 3D mesh of the aforementioned scene data, Using the position of the camera, the camera angle relative to the 3D mesh is calculated, The scene data is analyzed, and the position of potential lines is analyzed based on the camera angle relative to the 3D mesh. To generate a base curve for the position of the aforementioned potential line, Based on user input, a quadratic curve is generated on the base curve to produce a stylized curve, To have them do it, A non-temporary computer-readable storage medium characterized by the following features.

18. The non-temporary computer-readable storage medium according to claim 17, characterized in that the executable instruction causing the computer to generate the stylized curve includes an executable instruction causing the computer to assign characteristics including various taperings and offsets.

19. The non-temporary computer-readable storage medium according to claim 17, further comprising an executable instruction causing the computer to generate a set of multiple base curves and fade them in and out when the base curve lacks visual consistency.

20. Adding hand-drawn lines to the aforementioned stylized curves, Exporting vector data from a digital content creation application to generate a set of drawings, Interpolating the set of drawings and merging them with the stylized curves, Further includes an executable instruction that causes the computer to perform the following: A non-temporary computer-readable storage medium according to claim 17, characterized in that...

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