Visual Presentation

One screenshot of the visualized ecosystem is shown in figure 5.5. The small dots represent the agents and the large circle represents the influence range of the dominator.

Figure 5.5: The visualized ecosystem. 

The color map is based on [18]. The colors of agents and the dominator present different pairs of arousal and valence values. The color is coded in the HSB color mode.

HSB stands for hue, saturation, brightness. The color mapping is shown in figure 5.6. The brightness gets higher from low valence to high valence. The saturation gets higher from neutral to the extreme of the emotion. Through colors, users can identify how the agents’

attributes are similar to the dominator’s attributes in the visualized ecosystem.

Figure 5.6: The color mapping.

The motion graphics of agents and the dominator are produced using generative methods instead of the fixed animations. The shape of the dominator varies in a repetitive manner over time. The virtual creatures (agents) have pairs of wings which rotate over time as well. The variation rates of the shape of the dominator and the rotation of agents’

wings are pertaining to their own arousal values. The rotation of the agents’ wings is shown in figure 5.7.

Figure 5.7: Agents with different arousal values have different speed of rotation.

The left side shows slower rotation for lower arousal value. The right side shows faster rotation for higher arousal value.

The shape of the dominator is transformed while moving. Figure 5.8 shows the different types of the transformation. In the figure 5.8, the left column shows that the dominator is moving left or right, and the right column shows that the dominator is moving up or down. The middle shows that the dominator stays still.

Figure 5.8: Different types of the transformation.

By using the generative method, complex motion graphics can be created. Instead of making fixed animations in advance, the motion of the graphics can be defined by lines of program code. Sometimes, the motion is hard to be drawn by hand because the performance is too complex. The motion of the dominator can be defined as the following code:

userrotation+=(int)(user.arousal*10.0+12); // the amount of rotation each turn userrotation=userrotation%360;

radian=radians(userrotation); //covert degree to radian for(int a=1;a<17;a++){ //16 circles

float inc=(float)(TWO_PI/(100.0-a*3)); //interval between curves

fill((int) thecolor, 210 - a * 10, (int) (70 * user.valence + 110), 80); // set color for(float i=0;i<TWO_PI;i+=inc){

beginShape(); //each curve is defined by 4 curve vertex

//*3: the matrix is scaled from 256x256 to the image size 768x768

curveVertex(user.position_X * 3, user.position_Y * 3); curveVertex(user.position_X * 3 + 10 * a * cos(i),user.position_Y * 3 + 10 * a * sin(i));

if (morph == 0) //stay

curveVertex(user.position_X * 3 + 10 * a * cos(i) + 15* cos(i + radian), user.position_Y * 3 + 10 * a* sin(i) + 15 * sin(i + radian));

else if (morph == 1) //up or down

curveVertex(user.position_X * 3 + 10 * a * cos(i + radian)+ 15 * cos(i), user.position_Y * 3 + 10 * a* sin(i) + 15 * sin(i + radian));

else //left or right

curveVertex(user.position_X * 3 + 10 * a * cos(i) + 15* cos(i + radian), user.position_Y * 3 + 10 * a* sin(i + radian) + 15 * sin(i));

curveVertex(user.position_X * 3, user.position_Y * 3);

endShape();

} }

The dominator is composed of 16 circles from the center to the edge. Each circle is composed of different number of curves. The outer circle has the least number of curves.

Each turn every curve is rotated by little amount of radians to create the motion of the circle. The amount is proportional to the arousal value of the dominator. The type of the transformation can be easily swapped. As shown in the code, the variable ‘morph’ can be easily swapped by replacing one line of program code, to have the totally different motions. The color setting is also inserted in the loop. The saturation gets lower when drawing outer circle as shown in figure 5.8.

The motion of the agents is also created by a generative method. Because the rotation speed of each agent’s wings is different, many fixed animations have to be created in advance if the generative method is not used.

The system is built using Java, and Processing is used for the visual presentation.

Initially, the system generates agents with random positions. Their attributes are equally distributed on 4 quadrants of the arousal-valence plane. Then, the arousal and valence values of selected agents are sent to Max/Msp via Open Sound Control.

The user can observe the agents run to or away from the dominator for every action following principles described in previous sections. In this way, users can interactively affect the ecosystem. Because the artificial lives in the mapping platform are visualized on the screen, the mappings are no longer behind the scene but become a vivid visual presentation. The usage of the ecosystem does not only increase the variety and the

complexity of the soundscape, but also provides a gaming experience. The users can learn how to attract agents they want and how their gestures affect the ecosystem by watching the visual display as well as by listening to the audio.

Chapter 6

USER INTERFACE AND SYSTEM ARCHIETECURE

6.1 User interface

To control the dominator in the ecosystem, we design a scepter as the user interface.

The user, as the dominator, can conduct the ecosystem using the scepter and his gestures are interpreted into the arousal-valence plane. The scepter is shown in figure 6.1. It contains an Arduino microcontroller, a 3-axis accelerometer, a force sensing resistor (FSR) and a switch button. The accelerometer detects the direction of waving to control the movement of the dominator in the ecosystem. The force sensing resistor detects the pressure from the user. The switch button is placed at the bottom of the scepter. Every time the scepter hits the ground/surface, the switch is trigger once in order to detect the tempo of hitting. The pressure and the tempo are interpreted into the valence and arousal, respectively. The valence gets negative when the pressure gets higher. The arousal gets active when the tempo gets faster. These arousal and valence values are the attributes of the dominator. The mapping is not only for intuitive control, but also complying with the role of the dominator. The actions of pointing the direction and hitting the ground by using the scepter are suggestive of a ceremony where a chief or a king holds the scepter.

Figure 6.1: The user interface, Scepter. The switch button is at the bottom. The FSR is on the surface. The accelerometer and the Arduino microcontroller are inside the scepter.

6.2 System Architecture

The system architecture is shown in figure 6.2. The system except for sound synthesizer is built using Java. Especially, Processing is used to build the visual presentation. Serial handler reads the values from the sensors and interprets them into arousal/valence values of the dominator. Sound handler sends arousal/valence values acquired from the ecosystem to sound synthesizer via Open Sound Control. The sound synthesizer is made using Max/Msp.

Serial Handler

Ecosystem

Visual Presentation

using Processing

Sound Handler

Sensors connected with Arudino

Sound Synthesizer in Max/Msp Serial

Open Sound Control in Java

Figure 6.2: The system architecture.

Chapter 7

CONCLUSION

In this work, we produce an interactive soundscape by adopting a virtual ecosystem as the mapping platform. The soundscape does not imitate any places in the real world.

Instead, it is a virtual sound space comprised of certain nature sounds and synthetic sounds of the weather. Although the sounds we create are concrete, the overall soundscape generated from our interactive mappings can be imaginary with users’

creativity.

The interaction strategy we adopt is not a direct mapping from users’ gestures to parameters of sounds or music, but through an ecosystem for indirect mappings. The user, the dominator in the ecosystem, indirectly affects the soundscape by the collectivity of features of surrounding agents. In our work, agents in the ecosystem make sounds collectively, not like in other works where every agent or virtual creature makes sound individually.

Our interactive interface is designed to fit in the role of the dominator. It symbolizes the supreme power in the ecosystem. The visual display shows how the power is exerted and affects the environment. The state of the interaction is shown both in visual and in audio outputs.

In the Eco-Conductor, generative methods, which can produce surprising and amazing results are used in both audio and visual demonstrations. Usually, the results can be too complex to be created by hand. While pieces of fixed animations or discrete sound files are looped to produce limited variations, a well-designed generative method can

generate infinite results. The creation of a generative procedure can be regarded as the creation of art in an indirect way. Generative methods stem from a promising field of study as computers become more and more powerful. Many complex methods can be executed in real-time and bring amazing results.

We hope this work can provoke attentions to the soundscape of the environment we live in. In the future, we expect more creative art works involving usages of artificial lives in a virtual world.

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