The first step is to create the wireframe of the human using primitives. A frustum with variable elliptical cross-sections has been used as a building block for modelling the Kathakali dancer. The outer surface of this primitive is realised by a triangular mesh. A stack of such primitives are used to model the head, arms and body separately. Though the resolution can be easily controlled, a very high resolution is sacrificed for faster rendering.
The head has three degrees of freedom i.e.. it can be twisted, bent forward and sideways. Moreover, the movements are limited in the range that is humanely possible. To model the arms, first the shoulder joints with three degrees of freedom have been created. Next, the upper arm, the lower arm and the wrist are created using the frustum primitive. The elbow and wrist joints are simulated as hinge joints i.e.. with only one degree of freedom.
The Kathakali dance form is famous for its elaborate apparel and ornamentation. Hence, to give a realistic effect, texture mapping has been used to create an appropriate pattern on the front of the dress. The image used for texture mapping has been obtained from images of Kathakali dancers.
Various other Graphics rendering techniques like Lighting and Shading have been used to create the effect of a 3D Virtual World. The real time nature of the application requires the use of special techniques for optimizing performance.
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Figure 6: Graphics Modeling. The frustum primitive has been used in several constructions, for example the headgear shown to the right.
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Table: Modelling of Joints This Table shows the degrees-of-freedom and constraints of the labelled joints in Figure 7.
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Table: Number of Polygons This Table shows the number
of polygons used to create the model of Figure 7.
