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Hierarchic Pinball Method (2)
• Hierarchy stops when:
– Continuum: min size or max level is reached
– Shells: size equals physical element thickness
Level 0 (parent) Level 1
Level 2
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Contact Force Computation
• Constraints on velocities:
v ⋅nˆ −v ⋅nˆ ≤0
A
B
A
v A
n
B
v B
• By expanding the velocities:
n
n
A
B
i = ⋅ −
1 Ai Ai ∑i
= 1
⎡ ⎤ ⎡ ⎤
⎢ ⎥ ⎢ ⎥
⎢∑
⎥ ⎢
Bi Bi
⎥
⎢
⎣
⎥
⎦
⎢
⎣
⎥
⎦
N ( A ) v nˆ N ( B ) v ⋅nˆ≤0
• These inequalities are of the generic form:
Cv ≤ b
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