CN100587723C - Three-dimensional animations cartoon flame creation method - Google Patents

Abstract

The invention discloses a cartoon flame generation method of 3D animation; the method comprises the following steps: based on a hand-drawn cartoon flame sample, the contour line of the flame sample isextracted and drawn on a billboard, and the flame sample is deformed by the axial deformation technology to synthesize wind moving flame effect and flame propagation effect. The inside of the flame is drawn by colors with gradient change, and a shape is arranged at the foot segment of the flame to achieve the purpose that when watching the flame on the billboard from the top of the 3D space, theflame still brings people with certain stereoscopic impression. The cartoon flame generated by adopting the method can keep the quality of the hand-drawn cartoon flame, when the wind moving flame effect and the flame propagation effect are presented, a new flame animation sequence is avoided from redrawing, and the animation length is not limited. By adopting the method, cartoon moving line animation production efficiency can be greatly improved. As a system directly generates and saves animation sequence image, the method breaks away from the use of paper sheet which are required in hand-drawn cartoon flame and can save a great amount of paper sheets.

Description

The cartoon flame creation method of three-dimensional animation

Technical field

The present invention relates to cartoon special efficacy animation producing method, relate in particular to the cartoon flame creation method of three-dimensional animation.

Background technology

Effects such as flowing water, flame, smog all have crucial effect to the sense of reality of setting off animation atmosphere and enhancing animation by contrast in cartoon, and wherein flame effect is an object common in the animation, for example torch, bonfire, fire etc.The cartoon flame animation still relies on manual drawing at present, and the animation art designing approximately can draw 20 width of cloth left and right sides pictures (animation of about 1 second length) in one day, and a cartoon effect length was generally for 3～6 seconds, and artificial the drafting needs 4～5 days, inefficiency.If the wind effect of performance cartoon flame, or cartoon flame spread effect, the animate personnel need repaint new cartoon flame sequence, and are time-consuming, and the waste paper.

Area of computer aided is made animation system and is conceived to mainly realize some making step in the traditional-handwork animation with computer means that its main algorithm is key picture (Keyframe) interpolation at present.But these methods that generate midway film automatically require the object between the key picture all continuous on geometry and time.Because cartoon flame contains the random motion component, thereby has destroyed the corresponding relation between the picture, causes said method complete failure.In addition, cartoon flame is the two-dimensional picture with artistic style of manual drawing, and they are difficult to also can't utilize physical knowledge such as channel theory etc. that it is set up model with particIe system (Particle system) expression.People propose the animation producing method of many processing flames in two more than ten years in the past, but mostly are devoted to generate the animation of the sense of reality, and to the effective solution of the unmanned always proposition of automatic generation cartoon style flame animation.

Summary of the invention

The cartoon flame creation method that the purpose of this invention is to provide a kind of three-dimensional animation, only need specify a spot of reference mark and parameter just can generate random length automatically, not have the periodicity emphasis cartoon flame animation of mechanical sense again by this method user, comprise that specifically cartoon flame wind effect and cartoon flame spread effect.It is real-time that formation speed reaches.

To achieve these goals, the cartoon flame creation method of three-dimensional animation of the present invention is the cartoon flame sample based on manual drawing, and they are carried out deformation process, controls these models with parameter and generates corresponding cartoon style flame animation automatically.

The inventive method specifically may further comprise the steps:

1) the cartoon flame animation sequence of input manual drawing;

2) the cartoon flame image with input carries out the black and white binary conversion treatment;

3) utilize 8 neighborhood templates scanning cartoon flame image and extract flame contours;

4) the cartoon flame outline data that extracts is placed in the two-dimensional coordinate system;

5) with the SPL that is defined on the Y-axis arc length deformation coordinate axle is set;

6) input flame pattern instruction generates static cartoon flame profile diagram, wind cartoon flame profile diagram or cartoon flame and spreads profile diagram:

When if execution command is stationary flame, then:

Input cartoon flame location parameter;

Input cartoon flame size parameter;

Generate static cartoon flame profile diagram;

When if execution command is wind flame, then:

Input flame deflection angle;

Input flame vibration mode;

Generate wind cartoon flame profile diagram;

When if execution command is propagation of flame, then:

Input propagation of flame path;

Input flame stable state height;

Generate cartoon flame and spread profile diagram;

7) in the cartoon flame profile diagram, draw color;

8) cartoon flame is plotted on the billboard;

9) cartoon flame bottom 3D processing;

10) generate the output of cartoon flame animation and video.

Among the present invention, the SPL that said usefulness is defined on the Y-axis is provided with arc length deformation coordinate axle, comprises the steps:

A, establish

For being defined in interval [u ₀, u ₁] last SPL,

For

The normal vector function,

Arc length s can be expressed as:

$s\left(u\right)={\∫}_{u_1}^{u_0}{\left|\right|{\stackrel{\→}{R}}^{\′}\left(u\right)\left|\right|}^2\mathrm{du}$

$={\∫}_{u_1}^{u_0}\sqrt{{\left(x^{\′}\left(u\right)\right)}^2+{\left(y^{\′}\left(u\right)\right)}^2\mathrm{du}}$

B, make P (x, y) be on the cartoon flame profile a bit, the parameter of curve u of its corresponding arc length under not distortion situation _yCan be expressed as

u _y＝u ₀+(y-s ₀)/(s ₁-s ₀)*(u ₁-u ₀)

s ₀And s ₁The arc length of corresponding flame image height of difference and bottom;

C, utilize u _yCan on the axial curve of distortion, find a some R (u _y), (x y) can calculate by following formula new some position P on deformation space

${\stackrel{\→}{P}}_d=\stackrel{\→}{R}\left(u_y\right)+x\·\stackrel{\→}{N}\left(u_y\right)$

D, the cartoon flame sample is embedded in the shaft distortion coordinate system, calculates each coordinate in axle becomes coordinate system on the cartoon flame contours.

Among the present invention, said generation wind cartoon flame profile diagram comprises the steps:

A, utilization index function # _i=e ^-(1-i/N). Δ θ modulates deformed shaft, and Δ θ is the parameter of controlled deformation axle degree of deflection here, and i is i vector on the deformed shaft, and N is counting on the deformed shaft; Perhaps, utilize interpolation calculation to obtain a series of intermediate deformation axles according to manual position and the shape of specifying required deformed shaft of scene needs;

B, utilize principal axis transformation to calculate cartoon flame contours figure coordinate after the distortion on the deformed shaft.

Among the present invention, said generation cartoon flame spreads profile diagram, comprises the steps:

A, as a reference with X-axis, the definition cartoon flame spreads the flame size that enlarges gradually in the process;

B, the cartoon flame that spreads are divided into two parts: the transition section of flame head and thereafter stable state section, the transition section flame height by the end to height transition gradually, remain unchanged at stable state section flame height;

C, specify cartoon flame to spread the path alternately according to the scene needs;

D, input flame height parameter;

E, input cartoon rate of fire travel parameter;

F, cartoon flame according to command speed at the path vertical spread;

Among the present invention, that is washed draws color in the cartoon flame profile diagram, comprise the steps:

A, elder generation are depicted as redness to cartoon flame, get 1 p then on deformed shaft _c, with p _cBe the center, utilization index coefficient in the circle of radius r=1.1w

Control realizes orange-yellow to red gradual change from the center to the edge, and P is inner certain point of cartoon flame here, and w is the cartoon flame width;

B, to center of circle p _cAdd random perturbation, the irregular movement of simulation cartoon flame brightness;

C, in cartoon flame bottom to flame color with the background color interpolation, the translucent effect that simulation cartoon flame base is produced by thermal effect.

Among the present invention, said cartoon flame bottom 3D processing, step is as follows:

Place one with reference to oval at the cartoon flame root, on elliptic contour, add random perturbation and obtain some reference mark, again with SPL to these reference mark interpolation, obtain simulating the bottom profile of cartoon flame under the depression angle.

The cartoon flame creation method of three-dimensional animation of the present invention has the following advantages:

1. guaranteed that the cartoon flame that generates has the artistic characteristics of manual drawing cartoon flame, simultaneously two-dimensional cartoon flame expanded to three dimensions, flame size, just, movement velocity is parametrization and controls, and can adapt to the different scene needs in the cartoon.

2. the user only needs to import a small amount of reference mark alternately and parameter just can generate the cartoon flame animation that random length does not repeat mechanical sense, and this method is given birth to cartoon flame speed and reached real-time.Compare with manual drawing cartoon flame animation, can improve cartoon flame cartoon making efficient greatly.

3. this method directly generates the animation sequence image and preserves, and has broken away from the use of manual drawing cartoon flame animation to paper, thereby has saved a large amount of paper.

Description of drawings

Fig. 1 is three-dimensional animation cartoon flame product process figure of the present invention;

Fig. 2 is stationary flame product process figure;

Fig. 3 is wind flame product process figure;

Fig. 4 is the propagation of flame process flow diagram.

Embodiment

Further specify the present invention below in conjunction with accompanying drawing.

The cartoon flame product process of three-dimensional animation as shown in Figure 1, this flow process has the following steps successively:

1. cartoon flame sample pre-service:

1) the cartoon flame animation sequence of input manual drawing;

2) the cartoon flame image with input carries out the black and white binary conversion treatment;

3) utilize 8 neighborhood templates scanning cartoon flame image and extract flame contours;

8 neighborhood template marks are as follows:

-1，-1	0，-1	1，-1
			-1，0	0，0	1，0
-1，1	0，1	1，1

A. find one not the mark outline line on point and with its mark;

B. the point of this mark as the current search center and with (0 ,-1) as initial search direction;

C. clockwise direction search outline line in 8 neighborhood templates if do not find not mark a little, jumps to d, otherwise the point that mark searches and with it as new search center; On the new direction of search, repeat c;

D. jump to a up to not marking a little.

4) the cartoon flame outline data that extracts is placed in the two-dimensional coordinate system;

5) with the SPL that is defined on the Y-axis arc length deformation coordinate axle is set, step is as follows:

A, establish For being defined in interval [u ₀, u ₁] last SPL,

For The normal vector function,

Arc length s can be expressed as:

$s\left(u\right)={\∫}_{u_1}^{u_0}{\left|\right|{\stackrel{\→}{R}}^{\′}\left(u\right)\left|\right|}^2\mathrm{du}$

$={\∫}_{u_1}^{u_0}\sqrt{{\left(x^{\′}\left(u\right)\right)}^2+{\left(y^{\′}\left(u\right)\right)}^2\mathrm{du}}$

B, make P (x, y) be on the cartoon flame profile a bit, the parameter of curve u of its corresponding arc length under not distortion situation _yCan be expressed as

u _y＝u ₀+(y-s ₀)/(s ₁-s ₀)*(u ₁-u ₀)

s ₀And s ₁The arc length of corresponding flame image height of difference and bottom;

C, utilize u _yCan on the axial curve of distortion, find a some R (u _y), (x y) can calculate by following formula new some position P on deformation space

${\stackrel{\→}{P}}_d=\stackrel{\→}{R}\left(u_y\right)+x\·\stackrel{\→}{N}\left(u_y\right)$

D, the cartoon flame sample is embedded in the shaft distortion coordinate system, calculates each coordinate in axle becomes coordinate system on the cartoon flame contours.

2. input cartoon flame pattern instruction: type instruction comprises that Class1 generates static cartoon flame profile diagram, type 2 wind cartoon flame profile diagrams, and type 3 cartoon flames spread profile diagram:

When if execution command is Class1 (referring to Fig. 2 flow process), then:

Input cartoon flame location parameter;

Input cartoon flame size parameter;

Generate static cartoon flame profile diagram.

When if execution command is type 2 (referring to Fig. 3 flow process), then:

Input flame deflection angle;

Input flame vibration mode;

System default mode: a, utilization index function # _i=e ^-(1-i/N). Δ θ modulates deformed shaft, and Δ θ is the parameter of controlled deformation axle degree of deflection here, and i is i vector on the deformed shaft, and N is counting on the deformed shaft;

User interactions waves mode: according to manual position and the shape of specifying required deformed shaft of scene needs, utilize interpolation calculation to obtain a series of intermediate deformation axles;

B, utilize principal axis transformation to calculate cartoon flame contours figure coordinate after the distortion on the deformed shaft.

Generate wind cartoon flame profile diagram.

When if execution command is type 3 (referring to Fig. 4 flow process), then:

Input propagation of flame path;

Input flame stable state height;

A, as a reference with X-axis, the definition cartoon flame spreads the flame size that enlarges gradually in the process;

B, the cartoon flame that spreads are divided into two parts: the transition section of flame head and thereafter stable state section, the transition section flame height by the end to height transition gradually, remain unchanged at stable state section flame height;

C, specify cartoon flame to spread the path alternately according to the scene needs;

D, input flame height parameter;

E, input cartoon rate of fire travel parameter;

F, cartoon flame according to command speed at the path vertical spread;

Generate cartoon flame and spread profile diagram.

3. in the cartoon flame profile diagram, draw color:

A, elder generation are depicted as redness to cartoon flame, get 1 p then on deformed shaft _c, with p _cBe the center, utilization index coefficient in the circle of radius r=1.1w Control realizes orange-yellow to red gradual change from the center to the edge, and P is inner certain point of cartoon flame here, and w is the cartoon flame width;

B, to center of circle p _cAdd random perturbation, the irregular movement of simulation cartoon flame brightness;

C, in cartoon flame bottom to flame color with the background color interpolation, the translucent effect that simulation cartoon flame base is produced by thermal effect.

4. cartoon flame is plotted on the billboard (Billboard).

5. cartoon flame bottom 3D processing:

Place one with reference to oval at the cartoon flame root, on elliptic contour, add random perturbation and obtain some reference mark, again with SPL to these reference mark interpolation, obtain simulating the bottom profile of cartoon flame under the depression angle.

6. generate the cartoon flame animation and the cartoon flame animation that generates is output into video cartoon according to standard A VI form.

Claims (1)

1. the cartoon flame creation method of three-dimensional animation may further comprise the steps:

1) the cartoon flame animation sequence of input manual drawing;

2) the cartoon flame image with input carries out the black and white binary conversion treatment;

3) utilize 8 neighborhood templates scanning cartoon flame image and extract flame contours;

4) the cartoon flame outline data that extracts is placed in the two-dimensional coordinate system;

5) with the SPL that is defined on the Y-axis arc length deformation coordinate axle is set; Step is as follows:

A, establish $\stackrel{\→}{R}\left(u\right)=(x\left(u\right),y\left(u\right))$ For being defined in interval [u ₀, u ₁] last SPL,

For

The normal vector function, Arc length s can be expressed as:

$s\left(u\right)={\∫}_{u1}^{u_0}{\left|\right|{\stackrel{\→}{R}}^{\′}\left(u\right)\left|\right|}^2\mathrm{du}$

$={\∫}_{u1}^{u_0}\sqrt{{\left(x^{\′}\left(u\right)\right)}^2+{\left(y^{\′}\left(u\right)\right)}^2}\mathrm{du}$

B, make P (x, y) be on the cartoon flame profile a bit, the parameter of curve u of its corresponding arc length under not distortion situation _yCan be expressed as

u _y＝u ₀+(y-s ₀)/(s ₁-s ₀)*(u ₁-u ₀)

s ₀And s ₁The arc length of corresponding flame image height of difference and bottom;

C, utilize u _yCan on the axial curve of distortion, find a some R (u _y), (x y) can calculate by following formula new some position P on deformation space

${\stackrel{\→}{P}}_d=\stackrel{\→}{R}\left(u_y\right)+x\·\stackrel{\→}{N}\left(u_y\right)$

D, the cartoon flame sample is embedded in the shaft distortion coordinate system, calculates each coordinate in axle becomes coordinate system on the cartoon flame contours;

6) input flame pattern instruction generates static cartoon flame profile diagram, wind cartoon flame profile diagram or cartoon flame and spreads profile diagram:

When if execution command is stationary flame, then:

Input cartoon flame location parameter;

Input cartoon flame size parameter;

Generate static cartoon flame profile diagram;

When if execution command is wind flame, then:

Input flame deflection angle;

Input flame vibration mode;

Generate wind cartoon flame profile diagram; Concrete steps are:

A, utilization index function # _i=e ^-(1-i/N)Δ θ modulates deformed shaft, and Δ θ is the parameter of controlled deformation axle degree of deflection here, and i is i vector on the deformed shaft, and N is counting on the deformed shaft; Perhaps, utilize interpolation calculation to obtain a series of intermediate deformation axles according to manual position and the shape of specifying required deformed shaft of scene needs;

B, utilize principal axis transformation to calculate cartoon flame contours figure coordinate after the distortion on the deformed shaft.

When if execution command is propagation of flame, then:

Input propagation of flame path;

Input flame stable state height;

Generate cartoon flame and spread profile diagram; Concrete steps are:

A, as a reference with X-axis, the definition cartoon flame spreads the flame size that enlarges gradually in the process;

B, the cartoon flame that spreads are divided into two parts: the transition section of flame head and thereafter stable state section, the transition section flame height by the end to height transition gradually, remain unchanged at stable state section flame height;

C, specify cartoon flame to spread the path alternately according to the scene needs;

D, input flame height parameter;

E, input cartoon rate of fire travel parameter;

F, cartoon flame according to command speed at the path vertical spread;

7) in the cartoon flame profile diagram, draw color; Step is as follows:

A, elder generation are depicted as redness to cartoon flame, get 1 p then on deformed shaft _c, with p _cBe the center, utilization index coefficient in the circle of radius r=1.1w $\mathrm{\α}=e^{-\left(\right||P-P_c|\left|\right)}$ Control realizes orange-yellow to red gradual change from the center to the edge, and P is inner certain point of cartoon flame here, and w is the cartoon flame width;

B, to center of circle p _cAdd random perturbation, the irregular movement of simulation cartoon flame brightness;

C, in cartoon flame bottom to flame color with the background color interpolation, the translucent effect that simulation cartoon flame base is produced by thermal effect.

8) cartoon flame is plotted on the billboard;

9) cartoon flame bottom 3D processing; Step is as follows:

Place one with reference to oval at the cartoon flame root, on elliptic contour, add random perturbation and obtain some reference mark, again with SPL to these reference mark interpolation, obtain simulating the bottom profile of cartoon flame under the depression angle;

10) generate the output of cartoon flame animation and video.

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