ISPRS, Voi.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
413 
key frame 
Insert frame among key frame 
Figure 7 movie of key frame 
i»i 4 ¡<4>j * 4 
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Figure 8 slope and speed of movement 
After the attribute values of key frame is given, they will be 
stored in a structure named curve node and will be controlled 
by the node. These curves are defined by the attribute data of 
the key frame, the speed of the animation then can be 
adjusted by the tangent of a curve. 
Usually, (Fig 8)the gradient of a cun/e indicated the speed 
of an object. Steep curve indicates high speed, while flat for 
slow. Consequently, horizontal curve indicates the object 
stopped. 
During the mounting of ancient building, the order of 
mounting of different components is vitally important and 
restricted by their shapes and physical characteristics. Position 
of each component is measured by in situ surveying. The 
movement of components is strictly simulated according to the 
sequence of manually mounting these components. 
Pictures(Fig.9) is build-up process of timber components 
4.2 the establishment of key-frame 
Figure 9 movie of a series of dou-gong