CAVEActors:  A Human Actor Library For The CAVETM        Darren R. Thompson


III.    The Specifics of Each Part

    Each part of the body has a set of x-, y-, and z-minimum and rest rotation angles defined.  Each part of the actor has a color, ambient, diffuse, specular, shininess, and emission material property defined for it.  The eye has three parts, the pupil, iris, and main, for which all the material properties above are defined.  The head has five parts for which all the material properties above are defined.  These are the face (skin), lip, nostril, eyebrow, and hair.  The breasts inherit the material properties of the middle part of the torso.  All information about each part is stored in an ascii text file, called the actor-data file.

    There are convenience functions defined for each part of the body.  These can be found at the end of this report.  These functions take a direction, the number of degrees the programmer wants the part to rotate, along with three times.  The number of degrees is always positive.  The value of the degrees will be negated if necessary.  The possible values for the head, eyes and neck directions are shown in Figure 9.  The possible direction values for the torso, arms and hands are shown in Figure 10.  The possible values for the fingers and thumbs are shown in Figure 11.  Finally, the possible directions for the legs, feet and toes are shown in Figure 12.  If the number of degrees passed is greater than the limit, then the value is clamped to the min or max angle assigned.  Notice that not all parts are above, below or centered around the axes.  Each part was created at the point of rotation.  For example, the head rotates around the bottom vertex; whereas, the eye rotates around the center of the three axes.  There are functions which will place the part at any angle within the limitations assigned.  These functions take both negative and positive angles. Figure 13 shows the three axes along with the positive rotation directions.  This coordinate system applies in the OpenGL CAVETM library and 0,0,0 is at the center of the floor.

Figure 9  Possible directions for the head, eyes and neck.

Figure 10  Possible directions for the torso, arms and hands.

Figure 11  Possible directions for the fingers and thumbs.

Figure 12  Possible directions for the legs, feet and toes.

Figure 13  The coordinate system and positive rotation directions.