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82 CONTACT DETECTION
Level 5
Level 3
Discrete Level
element 4
Level 1
Level 2
Figure 3.8 Successive space subdivisions until the cell containing a discrete element is located.
Level 5 Level 4
Level 3
Level 2
Level 1 Root
Figure 3.9 Successive space subdivisions represented by a binary tree.
Contact detection consists of three steps:
• In the first step, all the discrete elements are mapped onto the cells.
• In the second step, this mapping is represented by the binary tree (i.e. binary tree
is built).
• In the third step, contact detection itself is performed.
It is worth mentioning that only cells with discrete elements mapped into them are rep-
resented by the binary tree. Thus, the size of the binary tree depends upon the number of
discrete elements present.
